So it looks like we'll be ultimately soldering a wire to TP1? And it looks like "solder wick" is the solder of choice. I've never heard of it and I've only used thick rosin-core solder with flux. It always seems to "run" where you don't want it to, and it large blobs. That's why I asked about soldering such a tiny hole. And then I think about all those tiny holes on the perfboard. How do you keep solder from·going every which way, into hole you don't want it to go into? Do you use a really tiny soldering tip (and a magnifying glass...?)
Tracy, speaking of "waste heat", we're looking into a solar (photovoltaic) array for our roof. If we don't feed excess electricity back into the grid, and if the storage batteries are fully charged, where does excess heat-energy from a PV array go? Is there·a "left-over electricity" device that dissipates or discharges(?) left-over voltage as heat-energy? (*not that we have excess sunlight·and solar·energy in New Hampshire. We don't. It's a theoretical question more relevant to Arizona I suppose.
The solar/storage battery question is interesting. I think we're going to find that understanding that kind of thing is important for all of us. I took a look at a system about two weeks ago, and learned a few things.
Re. solder wick, that's not a kind of solder, it's stuff that you use to wick up that solder that runs where you don't want it to. If you make a mistake, you can usually use solder wick to fix it.
The hole in TP1 should be pretty straightforward, though. Put the wire through, heat up the wire (NOT the solder!) with the tip of the soldering iron, and touch the solder to the wire and the pad around the hole. It should melt, settle into the hole, and be ready in just a couple of seconds. You could practice on perfboard (the kind with copper-ringed holes) before trying on the sensor itself.
================
Obviously I picked the wrong team in the World Cup.·Not only are the French not going to advance, it looks like they'll be hard-pressed to even·field a team for their third match.·It's as though the Packers made the playoffs and then decided not to·forfeit their playoff game. I'm sure glad I'm not in France now.
I see that Spain and Chile both won today. Chile looks likely to advance, and I think that Spain still has a shot. ·
It sounds like that solder wick will really make soldering easier for us, especially (as Mr. Kibler said) the hole is not very wide. After watching the tutorial on Youtube, it seems that you melt the solder onto the solder wick, but then what? The video I was watching didn't last long enough to show what happens next.
================================
Andrew,
Have fun in Florida! Hope to hear all about your trip at the next team meeting. Speaking of which, do you have an idea of when it may be?
Justin, I tried looking for more videos of the same thing on youtube but I couldn't find one good (and somewhat recent) video, I only had the time to watch 2 or 3 though, I had to leave for soccer. If you can find a longer one that shows more please let me know.
Thanks,
Mike
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ "Learn to obey before you command."
··· I get it... solder WICK, as in wicking up solder! That makes more sense. I've heard my friend Eric mention it before (what it does that is, which is to wick up excess solder.) But I never knew that's what it was·called. I'll have to wait until I get back to New Hampshire to do the soldering since that's where my soldering iron is (*unless of course I happen to get really eager and go to the Radio Shack that's conveniently located right down the street from the hotel. Is that karma, or coincidence...?)
I connected the wires from the ADC chip/ breadboard to the ASP-BOE like Tracy suggested below (including TP1 and TP3 which have wire through the holes, touching the copper.) The results were promising but cryptic. Two voltages (0 - 5.00 v) and their corresponding numbers (0 - 4096) were displayed as before, along with·the other ASP data. This time, however:
1) The higher of the two voltages dropped when CO2 was introduced into the sensor and then·increased back to 5.00 volts when the CO2 was "gone." The lower voltage (and its corresponding number) remained near 0. This could mean that the sensor did, in fact, register the CO2 as voltage.... progress if it did!
2) The voltages disappeared and then reappeared momentarily (for 1/2 - 1 second)·at 6-7 second intervals. The voltage dropped to 0 on both channels during intermission. The voltage readings did not stay on the screen constantly as before. OK, here's a "electronics for dummies" question. Sorry for asking. I assumed that, since the Rocketeers (and I) finished the potentiometer assignment on Sunday that I was starting from scratch with a bare breadboard. I removed everything from the breadboard except the ADC chip before wiring it to the BOE like Tracy explained above. That's how the breadboard is wired now. All the wires (capacitors, etc.) from the potientiometer exercise are stored away.
QUESTION: Should I have left anything on the breadboard other than·the ADC chip·(say, the capacitor we used for the potientiometer, the jump wire·connecting the capacitor and Vss to Vdd, other jump·wires, etc.)? It didn't seem to make sense that we would since the wires go to the ASP-BOE instead of the potentiometer/ BOE protoboard. But I have to ask. Better to safe than silly.
Speaking of 'Les Bleues', what a major meltdown, huh? So what's their game plan? L'equipe restent-ils 'en greve'? Will they bring in the third string or is the entire team boycotting?·"Les Suisse" (my homeland!) and the Chinese team are tied right now. You have to credit the Swiss·for taking a stance when it comes to neutrality, even in sports.·Conceding to a·0-0 draw is·a very·Swiss thing to do. How's "Italia! Italia! doing Tracy? Keeping track of which team is winning which bracket(?) is like remembering where the voltage goes after it leaves T1 and passes through the resistor...! Some many teams, so little time.
So what do I know about "football"? The Swiss are playing CHILE, not China. All I saw on the TV screen was CHI. I'm glad I didn't say they were playing Chicago!
The graph from the sensor documentation·(attached) shows that the relationship between voltage (mV) and CO2 concentration (ppm) is inverse, as expected. So that looks right. Is that it...?
Mark in NH said...
The graph from the sensor documentation·(attached) shows that the relationship between voltage (mV) and CO2 concentration (ppm) is inverse, as expected. So that looks right. Is that it...?
Brian B said...
To attach the co2 module just connect it to the app-mod slot on the board. it works just the same.
The pinouts on the app-mod connector are to the same pins as those found in the connectors along the edges of the protoboard, so yes, they could simply connect their wires from the 3202 to those pins. If you look at the photo of their board in the first page of this thread, you'll see that they're using almost all of the pin connectors along the edges of the protoboard, and none of the ones in the app-mod connector, so you're right - it might make things easier to plug the new wires in over there.
But the real issue they're butting up against is that they're running out of actual pins on the chip, and of course it doesn't matter whether you plug a wire into P7 along the edge of the protoboard or to P7 in the app-mod connector: you've used up P7 either way.
For reference, notice that they're going to need to connect the 3202 ADC chip (not the CO2 sensor) to the BoE. The CO2 sensor will connect to the 3202 chip (and of course to Vdd and Vss). The BS2 will only talk directly to the 3202, and will get data from the CO2 sensor indirectly through that chip.
======================
I need to add that I'm confused about the talk about a servo. It seems that I missed a year, but last year's project didn't use any servos, right? And I assume that this year's project doesn't either.
Finally, I'm wondering what it would take for me to come out to the launch. Do you typically fly into Reno, rent a car to·drive that city near Black Rocket, stay there and carpool somehow out to the launch site?
Man, it'd kill me to come out there without a rocket to launch on my own - it'd be the perfect opportunity to shoot for a mile, which I think is pretty much out of the question for me here at Bong Recreation Area (swamp, forests...). But of course there's no way to bring a rocket out there on a commercial airliner, and the drive is too far for me to make in the time I have. I wonder if I could convince Tim (Wildman) Lehr to attend the launch, and ferry a rocket out there for me. Hmm.
Post Edited (sylvie369) : 6/22/2010 1:26:29 PM GMT
Brian B said...
To attach the co2 module just connect it to the app-mod slot on the board. it works just the same.
Brian,
·· Thanks for your post. We have quite a little project going here.
I'm not sure what you mean when you say the "app-mod" slot. Which board is it on: the stand-alone breadboard we have the ADC chip installed on, or the BOE? So the CO2 sensor plugs in directly, like a "plug and play" application? We'll have to look into this. Our BOE board is already tight on physical space from other wires and sensors, as Sylvie noted. Thanks for the input. Stay tuned for details!
The "app mod" header is the black header with 2 rows of ten pin slots each, in the middle of your BoE. There are a few devices - a parallel·LCD with pushbuttons, for example, that I'm using - that do plug directly into that header. It's a much easier way of making a LOT of connections without running wires everywhere.
But no, the CO2 sensor cannot just be plugged into it. It's another place you could attach your wires - Vss and Vdd on the app-mod header rather than on the thin strips of headers next to the protoboard. But you'd still be plugging wires into little holes - just a set of holes a little removed from the current rats-nest.
This week I have baseball games in the evening everyday at 6:00. So that is why I have not been on in the evening. During the evening seems to be when everyone is posting on the forum also!
Sylvie,
If I recall correctly, doesn't ARLISS supply the rockets for you? Last year I believe that they supplied a rocket for us and for everyone else there.
Mr.Kibler, you took the words right out of my mouth. I search around on the internet and in the 'What's a Microcontroller' book and I could not find out what they were. I tried to search google images and that didn't work either. Sylvie, could you please explain what the app-mod slots are and where they are on the board?
I need to add that I'm confused about the talk about a servo. It seems that I missed a year, but last year's project didn't use any servos, right? And I assume that this year's project doesn't either.
Finally, I'm wondering what it would take for me to come out to the launch. Do you typically fly into Reno, rent a car to·drive that city near Black Rocket, stay there and carpool somehow out to the launch site?
Brian/ Sylvie, ·······So the single black strip of “holes” (p1, p3, etc.) in the center of the BOE is called the “app-mod” slot? Now I know, and so will the Rocketeers. This must be where “pin sharing” is done, yes? As Sylvie mentioned, we’re running out of physical space on the BOE board because of multiple other wires and sensors. And as he noted, the CO2 sensor and the ADC chip won’t be mounted directly on the BOE board: they’ll be mounted on our ASP-2 “satellite” then wired into the BOE board. ······Sylvie, the servos are for the treads on a BOE-bot we built as a clone so we could do prototyping on the smaller robot (Phidippides) we used the first year of the project. Phidippides was designed to measure and record temperature and humidity on a DataLogger as it descended. Then it was supposed to land and “run” across the ground (like Phidippides, the runner at the battle of Marathon), measuring baseline temperature and humidity.
We kept the “movement” subroutine in the program all along but it’s “turned off” (commented out) so the servos don’t run. Look at the bottom of the current program and you should see a ‘movement’ subroutine. I suspected what Tracy confirmed: the servos were getting “bleed over” voltage and, as a result, they were pulsing. I simply disconnected the servo wires from the BOE.
I’m actually visualizing next year’s project already! I’d love to see the robot do what it was originally designed to do 4 years ago. That is, ascend, descend, land, and then “run” across the surface measuring and recording temperature, humidity, elapsed time, altitude (and now, CO2 concentration.) This year’s ASP-2 will be proof-of-concept for·next year’s circuitry. In September 2011 we could mount the ASP-2 circuitry on a “mobile atmospheric sampling platform”, Phidippides-2, and ultimately accomplish what we wanted to four years ago with the NASA-SLI project. We could also launch the ASP-3 at Black Rock the same week. But I’m getting ahead of myself. Let’s get September, 2010 figured out first! Thanks, Tracy and Paul, for giving us the opportunity to dream and to help make these dreams a reality. I suppose I’m just a kid at heart. But I’m OK with that. Sylvie said, "Finally, I'm wondering what it would take for me to come out to the launch. Do you typically fly into Reno, rent a car to drive that city near Black Rocket, stay there and carpool somehow out to the launch site?"
We fly into Reno on Tuesday, September 14th at 2:00 PM and we leave on Saturday, September 18th at 10:30 AM. We could meet you (and Tracy?) at the airport and we could all carpool in the 12-passenger van we’re renting. There was plenty of room for 8 people in it last year and that’s how many we would have. We stay at the Best Western Inn in Fernley (1/2 hour from Reno. See attached photo) and we drive from there to Black Rock every day, returning to the hotel and dinner each evening. Several other teams stay there too since there isn’t much in Gerlach (the closest “town” to Black Rock.) You and Tracy would be our guests, our treat. You’ve done so much for our team and our project(s) already. That is the least we can do!
You should bring a rocket to launch at Black Rock! There are no fields to catch on fire like at Bong, and the altitude waiver is miles high! Literally. Could you ship it to the hotel in pieces? There’s so much else to do, too. Last year a teacher phoned from Gerlach. Her mother lives in New Hampshire and she read about the Rocketeers in the local paper, then contacted her daughter (the teacher.)
The teacher invited us to speak to students at Gerlach Middle-High School and we were received and feted liked kings and queens. They had an open house barbeque for us; they invited “our girls”, Mollie and Jessica, to play on the volleyball team (they were short on players); Mr. Moran (the husband and a gypsum mine supervisor) gave us a key to a private thermal hot springs; and we were given a tour of a private geyser, Fly Geyser (see attached.) We also took the Rocketeers on a rock-hunting field trip into an arroyo, and Susanne (my wife) made a wonderful picnic lunch. Finally, the science teacher, Mr. Beaver, also does rocketry. We may hook up with him and his students and take them on out to Black Rock for the launch...!·It's an·excellent, broad-based learning experience and it’s what education and learning should be. The rocket and the robot are simply the vehicles for·greater learning. We could even learn about wolf spiders and environmental science·if Tracy comes. Are there wolf spiders in Nevada...?
The Rocketeers came back with a much broader worldview (one Rocketeer had never been on a plane) and now everyone wants to be on “the rocket team.” It’s incredible—but true—that the school doesn’t fund the project and they only marginally support it. But I can’t let that dissuade me. ·If it’s “just a few” bucks here and there out-of-pocket, then that’s a small price to pay for some really great learning.
Attached are some pictures and links about "the trip to Black Rock". I think I’ll finish breakfast and walk·to the Radio Shack (conveniently located) across from the hotel. I suspect I’ll be buying a soldering iron and some solder wick.
Mark
1) A picture of the hot springs where we "cooled down" on the way back from Black Rock each day. BEAUTIFUL when the sun is setting over the hills...!
2) Downtown Gerlach... no hotels!
3) Don't know if I posted this before.·It's·a link to the presentation (video, PowerPoint, paper) I made about ARLISS at the International Space Symposium in France last February. Good info. for school groups, etc.
Mr. Kibler said, The results were promising but cryptic. Two voltages (0 - 5.00 v) and their corresponding numbers (0 - 4096) were displayed as before, along with the other ASP data. This time, however:
1) The higher of the two voltages dropped when CO2 was introduced into the sensor and then increased back to 5.00 volts when the CO2 was "gone." The lower voltage (and its corresponding number) remained near 0. This could mean that the sensor did, in fact, register the CO2 as voltage.... progress if it did!
Later on you verified that indeed there is an inverse relationship, the output voltage should drop when CO2 increases. The voltage that dropped was the one from TP1, right, because that is the sensor signal? TP3 is the output from the "calibration" potentiometer on the sensor module, the one you turn to set the point at which the LED turns on. By turning that, you should be able to see a voltage from 0 to 3.3 Volts, and a count from 0 to 2700. I am puzzled that your display showed (0 - 5.00 V) and (0 - 4096 counts). How could that happen? The sensor module has a 3.3V power supply and cannot output more than 3.3V!
2) The voltages disappeared and then reappeared momentarily (for 1/2 - 1 second) at 6-7 second intervals. The voltage dropped to 0 on both channels during intermission. The voltage readings did not stay on the screen constantly as before.
Hmmmm. I expect that is a programming issue with the display and the use of the pins. OK, here's a "electronics for dummies" question. Sorry for asking. I assumed that, since the Rocketeers (and I) finished the potentiometer assignment on Sunday that I was starting from scratch with a bare breadboard. I removed everything from the breadboard except the ADC chip before wiring it to the BOE like Tracy explained above. That's how the breadboard is wired now. All the wires (capacitors, etc.) from the potientiometer exercise are stored away.
QUESTION: Should I have left anything on the breadboard other than the ADC chip (say, the capacitor we used for the potientiometer, the jump wire connecting the capacitor and Vss to Vdd, other jump wires, etc.)? It didn't seem to make sense that we would since the wires go to the ASP-BOE instead of the potentiometer/ BOE protoboard. But I have to ask. Better to safe than silly.
Yes, leave the capacitor. It stablizes the power supply right next to the chip and is especially important when there are longish wires connecting the chip to the power supply. The leads of the capacitor should be short where they connect to the chip, to jump right between the two power pins.
Andrew let it be known that "Phidippides" from previous years has retired and is about to enter the droid recycling program. If there is no need for the servos this time around, that means you will also have pins p14 and p15 available.
Christopher should have a great education in international relations at GWU. I went to high school just across the Potomac River, and as a high school senior we liked to go into Georgetown. There was a club called "The Tombs" that was popular with the GWU students. Maybe it is still there. I remember the bouncers were really tough on high school students at 17 years old!
Sorry, France is really out of it now after today's loss to South Africa. A sad tournament, with a demoralizing red card too.
·· I thought you were a West Coast guy through and through. I was surprised to hear that you grew up on the banks of the Portomac (though I'm not sure why I would be.) I wonder if "The Tombs" is still there in G'town? Maybe Christopher and I should check it out tomorrow evening after he's finished with orientation...
Here's the latest on the voltage read-outs:
1) The two voltages do NOT "pulse rhythmically" as I thought earlier. They change intermittently. Watching the screen output data for 55 minutes shows this.
2) The higher of the two voltages·DOES exceed 3.3 volts (on the computer screen·anyway.) It's highest value (the voltage where it always seems to "start") is 5.006 volts, with a corresponding number·of 4095.
3) When the upper voltage drops from 5.006 it "seems" to drop in·1/2, 1/4, 1/8-step increments (e.g. 2.504 volts and 2048, which is 1/2 of 5.006 volts and 4095. Also noted 4.993 v - 4084,·1.252 v - 1024, 4.066 v - 4.971, etc.)
4) The lower voltage is always very low, less than 1.0 volts. It "starts" at 0.055 volts with a corresponding number of·255. When it drops to·0 - 0, this is the highest number (0.055 v -255) to which it·"resets". Observed these values: 0.055 v - 255, 0.038 v - 241,·0.155 v - 127, 0.017 - 224, etc.) No apparent 1/2, 1/4, 1/8 step incremental drop.
5) When the red LED alarm light lights up on the CO2 sensor, nothing happens·to the·voltages.
6) Adjusting the potientiometer on the CO2 sensor does nothing to voltage.
7) "Breathing" CO2 on the sensor seems (I emphasize "seems") to cause voltage to change. Increased CO2 causes decreased voltage, especially with the lower voltage/number. But the voltages/numbers "dance" all over the place·with no real pattern. I would expect·to see voltage·climb steadily·as CO2 purges from the sensor (if it is sensing CO2). But the voltage/numbers "dance".
Just to confirm, the wires from the CO2 sensor do go to:
Vin to Vin
Vss to Vss
CNTRL (HSW) to P4, with an in-line resistor
ALR to P3, with an in-line resistor
I'll triple check the wiring from the breadboard to the BOE again as you listed it. Also, I'd really like to get the wires·that go from·TP1 - CH0, and TP3 - CH1 soldered to the CO2 sensor's PCB.·Didn't get to Radio Shack yet. Right now the wires are·just "tucked in" to·the TP holes. The capacitor·IS connected between the Vss and Vdd pins on the AD chip.
If the CO2 sensor is sensing CO2, response time from sensing CO2 back to ambient conditions seems slow.
... and the metal CO2 sensor itself sure·does get·hot after running for an hour on AC power.·This confirms that we'll need a very dependable battery power supply in Nevada, as someone mentioned pages back.
Thanks Brian B, I think we were wondering that at one of our meetings? Correct me Mr. Kibler if I'm wrong... I think it was a question similiar to that anyways.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ "Learn to obey before you command."
·· What I mean by a "dependable" battery is one that has more than enough power (that is, amperage, or "amp-hours") to keep the ASP-2 powered throughout·its·2- or 3-hour·long mission. I recall that either Dr. Allen or Sylvie discussed this in a previous post, waaaaaaaaaay back.·Everything connected with the ASP uses power (draws amperage) in one way or another. That includes the BOE's circuit board, the BS2e·chip,·the MAWD,·DataLogger, flash drive, and now the CO2 sensor.
The reason I mentioned·this was because I noticed the CO2 sensor·(the round metal part)·was really hot after·it had been running·for 1-1/2 hours. Heat = energy, and so I speculated that the CO2 sensor's heater·draws a lot of amperage (electrial energy, or "battery power".) Check it·out. I think it's in the CO2 sensor's documentation sheet.·Last year the ASP-1 was running inside the rocket for nearly 30 minutes before the rocket left the launch pad. The ASP descended slowly for over 26 minutes, then·we had to track it with a GPS/ short wave tracking device, then locate it. Total elapsed time from power-up (turning·the ASP·on) to power-down (turning it off) was well over an hour... and the ASP-1 was relatively easy to locate on the desert floor, and it didn't have a CO2 sensor heater.
For·"safety" (so we don't lose data, the ASP, etc.)·we must be sure that·our battery stores at least twice the amp-hours we think we might need. Three times the amount needed would be even better. That's why, when the ASP-2 is wired, programmed, and fully operational, we'll "bench-test" it. That means we'll power it up and let it run and run and run, on battery power, so we can be certain that we have·sufficient power (in case it takes a long time to launch or to locate on the desert floor.)
We can also measure how much·amperage each device draws and then calcualte how long the battery should last. Typically aerospace engineers do both: they calculate the required amperage (first), then bench test the device to see if their calculations are accurate. Then they add a "safety margin" of extra amperage 'just in case.' NASA also uses a 'redundant' system. They include two or even three batteries, connected separately, just in case one--or two--fail.·Also, data is usually stored as·"non-volatile data." That means if power is lost, data isn't. The data is safely stored somewhere (on a flash drive, etc.) "Volatile data" is data that geos away when power is lost... not a good idea!
ROCKETEERS --->
GIVEN: Our battery is a rechargeable 9.2 volt, 5,000 mAH Ni-Cd (nickle-cadmium) battery.
QUESTION:·Will our battery be "dependable" enough for the mission we have planned? Yes, or no? Defend your answer with facts and details, not vague speculation·or science fiction. If you're not certain, write a simple plan explaining how we can/should find out. ·
From DC,
Mr. Kibler
(PS to Justin): It's Mr.·KIBLER, not "Killer"... see you last e-mail!) ···And I was your teacher ALL YEAR!··
Dear Mr. Kibler,
Well, to answer your ,"reliable battery" question, we would need to know 3 things.
1.) What is the total Amp drainage of the current ASP build?
2.) What is the combined Voltage requirement of the current ASP build?
3.) What are some Voltage limits of some of the components on the current ASP build? With the one you had last year, some resistors could of been optional due to the amount of power the battery supplied not being over the limit. With a possibly higher voltage on this battery, some resistors/potentiometers could be needed.
If we can factor this all in then look at the battery you posted we could find out if this is a, "reliable" battery. I do not have the specs of the ASP-2, restricting me of answering in sure terms. Or is this a question that can be answered more easily? If I am mistaken, please someone guide me into the correct direction.
"NiMH" redirects here. For other uses, see NIMH (disambiguation).
Nickel-metal hydride battery
Modern, high capacity NiMH rechargeable cells
Energy/weight 30–80 W·h/kg
Energy/size 140–300 W·h/L
Power/weight 250–1000 W/kg
Charge/discharge efficiency 66%
Energy/consumer-price 2.75 W·h/US$
Self-discharge rate 30%/month (temperature dependent)
Time durability Citation Needed
Cycle durability 500–1,000
Nominal cell voltage 1.2 V
A nickel-metal hydride cell, abbreviated NiMH, is a type of secondary electrochemical cell similar to the nickel-cadmium cell. The NiMH battery uses a hydrogen-absorbing alloy for the negative electrode instead of cadmium. As in NiCd cells, the positive electrode is nickel oxyhydroxide (NiOOH). A NiMH battery can have two to three times the capacity of an equivalent size nickel-cadmium battery. However, compared to the lithium-ion cell, the volumetric energy density is lower and self-discharge is higher. (Compare: low self-discharge NiMH battery)
Disassembled NiMH AA cell:
1 - Positive terminal
2 - Outer metal casing (also negative terminal)
3 - Positive electrode
4 - Negative electrode with current collector (metal grid, connected to metal casing)
5 - Separator (between electrodes).Common AA cells (penlight-size) NiMH batteries have nominal charge capacities (C) ranging from 1100 mA·h to 2900 mA·h at 1.2 V, usually measured at a discharge rate of 0.2×C per hour. Useful discharge capacity is a decreasing function of the discharge rate, but up to a rate of around 1×C (full discharge in one hour), it does not differ significantly from the nominal capacity.
The specific energy density for NiMH material is approximately 70 W·h/kg (250 kJ/kg), compared to 40–60 W·h/kg for the more common nickel-cadmium, or 100-160 W·h/kg for Li-ion. NiMH has a volumetric energy density of about 300 W·h/L (1080 MJ/m³), significantly better than nickel-cadmium at 50–150 Wh/L, and about the same as Li-ion at 250-360 W·h/L.
I honestly didn't know how to simplify that... so I just copied and pasted, I thought it might be easier to understand in their words rather then to listen to me attempt to simplify it...
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ "Learn to obey before you command."
A thorough answer Mike, almost too much information. Look at the picture again... closely. On the label it says "Nickel metal hydride battery", or NiMh.
Dylan, you could look at the documentation sheets for each of the parts on the ASP. See what each requires for amperage and then do the math. For example, if the total amperage "draw" (usage) for all the parts happened to be 1000 mA, and if the battery is a 5000 mAH battery, then it should run the ASP-2 for 5 hours. But I don't think the ASP will draw nearly that much amperage each hour, even with the CO2 sensor's heater going.
Dr. Allen and Sylvie, and I am the right track here? Can you help clarify power useage requirements to the Rocketeers?
Comments
Re. solder wick, that's not a kind of solder, it's stuff that you use to wick up that solder that runs where you don't want it to. If you make a mistake, you can usually use solder wick to fix it.
The hole in TP1 should be pretty straightforward, though. Put the wire through, heat up the wire (NOT the solder!) with the tip of the soldering iron, and touch the solder to the wire and the pad around the hole. It should melt, settle into the hole, and be ready in just a couple of seconds. You could practice on perfboard (the kind with copper-ringed holes) before trying on the sensor itself.
================
Obviously I picked the wrong team in the World Cup.·Not only are the French not going to advance, it looks like they'll be hard-pressed to even·field a team for their third match.·It's as though the Packers made the playoffs and then decided not to·forfeit their playoff game. I'm sure glad I'm not in France now.
I see that Spain and Chile both won today. Chile looks likely to advance, and I think that Spain still has a shot. ·
================================
Andrew,
Have fun in Florida! Hope to hear all about your trip at the next team meeting. Speaking of which, do you have an idea of when it may be?
Staying tuned!
Justin
Thanks,
Mike
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"Learn to obey before you command."
-Solon
··· I get it... solder WICK, as in wicking up solder! That makes more sense. I've heard my friend Eric mention it before (what it does that is, which is to wick up excess solder.) But I never knew that's what it was·called. I'll have to wait until I get back to New Hampshire to do the soldering since that's where my soldering iron is (*unless of course I happen to get really eager and go to the Radio Shack that's conveniently located right down the street from the hotel. Is that karma, or coincidence...?)
I connected the wires from the ADC chip/ breadboard to the ASP-BOE like Tracy suggested below (including TP1 and TP3 which have wire through the holes, touching the copper.) The results were promising but cryptic. Two voltages (0 - 5.00 v) and their corresponding numbers (0 - 4096) were displayed as before, along with·the other ASP data. This time, however:
1) The higher of the two voltages dropped when CO2 was introduced into the sensor and then·increased back to 5.00 volts when the CO2 was "gone." The lower voltage (and its corresponding number) remained near 0. This could mean that the sensor did, in fact, register the CO2 as voltage.... progress if it did!
2) The voltages disappeared and then reappeared momentarily (for 1/2 - 1 second)·at 6-7 second intervals. The voltage dropped to 0 on both channels during intermission. The voltage readings did not stay on the screen constantly as before.
OK, here's a "electronics for dummies" question. Sorry for asking. I assumed that, since the Rocketeers (and I) finished the potentiometer assignment on Sunday that I was starting from scratch with a bare breadboard. I removed everything from the breadboard except the ADC chip before wiring it to the BOE like Tracy explained above. That's how the breadboard is wired now. All the wires (capacitors, etc.) from the potientiometer exercise are stored away.
QUESTION: Should I have left anything on the breadboard other than·the ADC chip·(say, the capacitor we used for the potientiometer, the jump wire·connecting the capacitor and Vss to Vdd, other jump·wires, etc.)? It didn't seem to make sense that we would since the wires go to the ASP-BOE instead of the potentiometer/ BOE protoboard. But I have to ask. Better to safe than silly.
Speaking of 'Les Bleues', what a major meltdown, huh? So what's their game plan? L'equipe restent-ils 'en greve'? Will they bring in the third string or is the entire team boycotting?·"Les Suisse" (my homeland!) and the Chinese team are tied right now. You have to credit the Swiss·for taking a stance when it comes to neutrality, even in sports.·Conceding to a·0-0 draw is·a very·Swiss thing to do. How's "Italia! Italia! doing Tracy? Keeping track of which team is winning which bracket(?) is like remembering where the voltage goes after it leaves T1 and passes through the resistor...! Some many teams, so little time.
·
So what did I miss?
I'll ponder the BOE-bot
(And cheer for the Swiss!)
I'll take another look at the sensor's data sheet.
Thanks Paul,
Mark
But the real issue they're butting up against is that they're running out of actual pins on the chip, and of course it doesn't matter whether you plug a wire into P7 along the edge of the protoboard or to P7 in the app-mod connector: you've used up P7 either way.
For reference, notice that they're going to need to connect the 3202 ADC chip (not the CO2 sensor) to the BoE. The CO2 sensor will connect to the 3202 chip (and of course to Vdd and Vss). The BS2 will only talk directly to the 3202, and will get data from the CO2 sensor indirectly through that chip.
======================
I need to add that I'm confused about the talk about a servo. It seems that I missed a year, but last year's project didn't use any servos, right? And I assume that this year's project doesn't either.
Finally, I'm wondering what it would take for me to come out to the launch. Do you typically fly into Reno, rent a car to·drive that city near Black Rocket, stay there and carpool somehow out to the launch site?
Man, it'd kill me to come out there without a rocket to launch on my own - it'd be the perfect opportunity to shoot for a mile, which I think is pretty much out of the question for me here at Bong Recreation Area (swamp, forests...). But of course there's no way to bring a rocket out there on a commercial airliner, and the drive is too far for me to make in the time I have. I wonder if I could convince Tim (Wildman) Lehr to attend the launch, and ferry a rocket out there for me. Hmm.
Post Edited (sylvie369) : 6/22/2010 1:26:29 PM GMT
·· Thanks for your post. We have quite a little project going here.
I'm not sure what you mean when you say the "app-mod" slot. Which board is it on: the stand-alone breadboard we have the ADC chip installed on, or the BOE? So the CO2 sensor plugs in directly, like a "plug and play" application? We'll have to look into this. Our BOE board is already tight on physical space from other wires and sensors, as Sylvie noted. Thanks for the input. Stay tuned for details!
Mark and the Rocketeers
The "app mod" header is the black header with 2 rows of ten pin slots each, in the middle of your BoE. There are a few devices - a parallel·LCD with pushbuttons, for example, that I'm using - that do plug directly into that header. It's a much easier way of making a LOT of connections without running wires everywhere.
But no, the CO2 sensor cannot just be plugged into it. It's another place you could attach your wires - Vss and Vdd on the app-mod header rather than on the thin strips of headers next to the protoboard. But you'd still be plugging wires into little holes - just a set of holes a little removed from the current rats-nest.
This week I have baseball games in the evening everyday at 6:00. So that is why I have not been on in the evening. During the evening seems to be when everyone is posting on the forum also!
Sylvie,
If I recall correctly, doesn't ARLISS supply the rockets for you? Last year I believe that they supplied a rocket for us and for everyone else there.
Mr.Kibler, you took the words right out of my mouth. I search around on the internet and in the 'What's a Microcontroller' book and I could not find out what they were. I tried to search google images and that didn't work either. Sylvie, could you please explain what the app-mod slots are and where they are on the board?
Thank you all for your time and help,
Sean
Your recent post about the app-mod spots where you explained what they were wasn't showing when I had written my previous post asking about them.
Sean
·······So the single black strip of “holes” (p1, p3, etc.) in the center of the BOE is called the “app-mod” slot? Now I know, and so will the Rocketeers. This must be where “pin sharing” is done, yes? As Sylvie mentioned, we’re running out of physical space on the BOE board because of multiple other wires and sensors. And as he noted, the CO2 sensor and the ADC chip won’t be mounted directly on the BOE board: they’ll be mounted on our ASP-2 “satellite” then wired into the BOE board.
······Sylvie, the servos are for the treads on a BOE-bot we built as a clone so we could do prototyping on the smaller robot (Phidippides) we used the first year of the project. Phidippides was designed to measure and record temperature and humidity on a DataLogger as it descended. Then it was supposed to land and “run” across the ground (like Phidippides, the runner at the battle of Marathon), measuring baseline temperature and humidity.
We kept the “movement” subroutine in the program all along but it’s “turned off” (commented out) so the servos don’t run. Look at the bottom of the current program and you should see a ‘movement’ subroutine. I suspected what Tracy confirmed: the servos were getting “bleed over” voltage and, as a result, they were pulsing. I simply disconnected the servo wires from the BOE.
I’m actually visualizing next year’s project already! I’d love to see the robot do what it was originally designed to do 4 years ago. That is, ascend, descend, land, and then “run” across the surface measuring and recording temperature, humidity, elapsed time, altitude (and now, CO2 concentration.) This year’s ASP-2 will be proof-of-concept for·next year’s circuitry. In September 2011 we could mount the ASP-2 circuitry on a “mobile atmospheric sampling platform”, Phidippides-2, and ultimately accomplish what we wanted to four years ago with the NASA-SLI project. We could also launch the ASP-3 at Black Rock the same week. But I’m getting ahead of myself. Let’s get September, 2010 figured out first! Thanks, Tracy and Paul, for giving us the opportunity to dream and to help make these dreams a reality. I suppose I’m just a kid at heart. But I’m OK with that.
Sylvie said, "Finally, I'm wondering what it would take for me to come out to the launch. Do you typically fly into Reno, rent a car to drive that city near Black Rocket, stay there and carpool somehow out to the launch site?"
We fly into Reno on Tuesday, September 14th at 2:00 PM and we leave on Saturday, September 18th at 10:30 AM. We could meet you (and Tracy?) at the airport and we could all carpool in the 12-passenger van we’re renting. There was plenty of room for 8 people in it last year and that’s how many we would have. We stay at the Best Western Inn in Fernley (1/2 hour from Reno. See attached photo) and we drive from there to Black Rock every day, returning to the hotel and dinner each evening. Several other teams stay there too since there isn’t much in Gerlach (the closest “town” to Black Rock.) You and Tracy would be our guests, our treat. You’ve done so much for our team and our project(s) already. That is the least we can do!
You should bring a rocket to launch at Black Rock! There are no fields to catch on fire like at Bong, and the altitude waiver is miles high! Literally. Could you ship it to the hotel in pieces? There’s so much else to do, too. Last year a teacher phoned from Gerlach. Her mother lives in New Hampshire and she read about the Rocketeers in the local paper, then contacted her daughter (the teacher.)
The teacher invited us to speak to students at Gerlach Middle-High School and we were received and feted liked kings and queens. They had an open house barbeque for us; they invited “our girls”, Mollie and Jessica, to play on the volleyball team (they were short on players); Mr. Moran (the husband and a gypsum mine supervisor) gave us a key to a private thermal hot springs; and we were given a tour of a private geyser, Fly Geyser (see attached.) We also took the Rocketeers on a rock-hunting field trip into an arroyo, and Susanne (my wife) made a wonderful picnic lunch. Finally, the science teacher, Mr. Beaver, also does rocketry. We may hook up with him and his students and take them on out to Black Rock for the launch...!·It's an·excellent, broad-based learning experience and it’s what education and learning should be. The rocket and the robot are simply the vehicles for·greater learning. We could even learn about wolf spiders and environmental science·if Tracy comes. Are there wolf spiders in Nevada...?
The Rocketeers came back with a much broader worldview (one Rocketeer had never been on a plane) and now everyone wants to be on “the rocket team.” It’s incredible—but true—that the school doesn’t fund the project and they only marginally support it. But I can’t let that dissuade me. ·If it’s “just a few” bucks here and there out-of-pocket, then that’s a small price to pay for some really great learning.
Attached are some pictures and links about "the trip to Black Rock". I think I’ll finish breakfast and walk·to the Radio Shack (conveniently located) across from the hotel. I suspect I’ll be buying a soldering iron and some solder wick.
Mark
1) A picture of the hot springs where we "cooled down" on the way back from Black Rock each day. BEAUTIFUL when the sun is setting over the hills...!
2) Downtown Gerlach... no hotels!
3) Don't know if I posted this before.·It's·a link to the presentation (video, PowerPoint, paper) I made about ARLISS at the International Space Symposium in France last February. Good info. for school groups, etc.
http://www.isunet.edu/index.php?option=com_docman&task=cat_view&gid=259&Itemid=88888955
Mark
The results were promising but cryptic. Two voltages (0 - 5.00 v) and their corresponding numbers (0 - 4096) were displayed as before, along with the other ASP data. This time, however:
1) The higher of the two voltages dropped when CO2 was introduced into the sensor and then increased back to 5.00 volts when the CO2 was "gone." The lower voltage (and its corresponding number) remained near 0. This could mean that the sensor did, in fact, register the CO2 as voltage.... progress if it did!
Later on you verified that indeed there is an inverse relationship, the output voltage should drop when CO2 increases. The voltage that dropped was the one from TP1, right, because that is the sensor signal? TP3 is the output from the "calibration" potentiometer on the sensor module, the one you turn to set the point at which the LED turns on. By turning that, you should be able to see a voltage from 0 to 3.3 Volts, and a count from 0 to 2700. I am puzzled that your display showed (0 - 5.00 V) and (0 - 4096 counts). How could that happen? The sensor module has a 3.3V power supply and cannot output more than 3.3V!
2) The voltages disappeared and then reappeared momentarily (for 1/2 - 1 second) at 6-7 second intervals. The voltage dropped to 0 on both channels during intermission. The voltage readings did not stay on the screen constantly as before.
Hmmmm. I expect that is a programming issue with the display and the use of the pins.
OK, here's a "electronics for dummies" question. Sorry for asking. I assumed that, since the Rocketeers (and I) finished the potentiometer assignment on Sunday that I was starting from scratch with a bare breadboard. I removed everything from the breadboard except the ADC chip before wiring it to the BOE like Tracy explained above. That's how the breadboard is wired now. All the wires (capacitors, etc.) from the potientiometer exercise are stored away.
QUESTION: Should I have left anything on the breadboard other than the ADC chip (say, the capacitor we used for the potientiometer, the jump wire connecting the capacitor and Vss to Vdd, other jump wires, etc.)? It didn't seem to make sense that we would since the wires go to the ASP-BOE instead of the potentiometer/ BOE protoboard. But I have to ask. Better to safe than silly.
Yes, leave the capacitor. It stablizes the power supply right next to the chip and is especially important when there are longish wires connecting the chip to the power supply. The leads of the capacitor should be short where they connect to the chip, to jump right between the two power pins.
Andrew let it be known that "Phidippides" from previous years has retired and is about to enter the droid recycling program. If there is no need for the servos this time around, that means you will also have pins p14 and p15 available.
Christopher should have a great education in international relations at GWU. I went to high school just across the Potomac River, and as a high school senior we liked to go into Georgetown. There was a club called "The Tombs" that was popular with the GWU students. Maybe it is still there. I remember the bouncers were really tough on high school students at 17 years old!
Sorry, France is really out of it now after today's loss to South Africa. A sad tournament, with a demoralizing red card too.
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Tracy Allen
www.emesystems.com
·· I thought you were a West Coast guy through and through. I was surprised to hear that you grew up on the banks of the Portomac (though I'm not sure why I would be.) I wonder if "The Tombs" is still there in G'town? Maybe Christopher and I should check it out tomorrow evening after he's finished with orientation...
Here's the latest on the voltage read-outs:
1) The two voltages do NOT "pulse rhythmically" as I thought earlier. They change intermittently. Watching the screen output data for 55 minutes shows this.
2) The higher of the two voltages·DOES exceed 3.3 volts (on the computer screen·anyway.) It's highest value (the voltage where it always seems to "start") is 5.006 volts, with a corresponding number·of 4095.
3) When the upper voltage drops from 5.006 it "seems" to drop in·1/2, 1/4, 1/8-step increments (e.g. 2.504 volts and 2048, which is 1/2 of 5.006 volts and 4095. Also noted 4.993 v - 4084,·1.252 v - 1024, 4.066 v - 4.971, etc.)
4) The lower voltage is always very low, less than 1.0 volts. It "starts" at 0.055 volts with a corresponding number of·255. When it drops to·0 - 0, this is the highest number (0.055 v -255) to which it·"resets". Observed these values: 0.055 v - 255, 0.038 v - 241,·0.155 v - 127, 0.017 - 224, etc.) No apparent 1/2, 1/4, 1/8 step incremental drop.
5) When the red LED alarm light lights up on the CO2 sensor, nothing happens·to the·voltages.
6) Adjusting the potientiometer on the CO2 sensor does nothing to voltage.
7) "Breathing" CO2 on the sensor seems (I emphasize "seems") to cause voltage to change. Increased CO2 causes decreased voltage, especially with the lower voltage/number. But the voltages/numbers "dance" all over the place·with no real pattern. I would expect·to see voltage·climb steadily·as CO2 purges from the sensor (if it is sensing CO2). But the voltage/numbers "dance".
Just to confirm, the wires from the CO2 sensor do go to:
Vin to Vin
Vss to Vss
CNTRL (HSW) to P4, with an in-line resistor
ALR to P3, with an in-line resistor
I'll triple check the wiring from the breadboard to the BOE again as you listed it. Also, I'd really like to get the wires·that go from·TP1 - CH0, and TP3 - CH1 soldered to the CO2 sensor's PCB.·Didn't get to Radio Shack yet. Right now the wires are·just "tucked in" to·the TP holes. The capacitor·IS connected between the Vss and Vdd pins on the AD chip.
If the CO2 sensor is sensing CO2, response time from sensing CO2 back to ambient conditions seems slow.
Mark
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"Learn to obey before you command."
-Solon
What kind of "dependable" battery do you mean? Like a brand new one, or a particular brand?
Justin
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"Learn to obey before you command."
-Solon
·· What I mean by a "dependable" battery is one that has more than enough power (that is, amperage, or "amp-hours") to keep the ASP-2 powered throughout·its·2- or 3-hour·long mission. I recall that either Dr. Allen or Sylvie discussed this in a previous post, waaaaaaaaaay back.·Everything connected with the ASP uses power (draws amperage) in one way or another. That includes the BOE's circuit board, the BS2e·chip,·the MAWD,·DataLogger, flash drive, and now the CO2 sensor.
The reason I mentioned·this was because I noticed the CO2 sensor·(the round metal part)·was really hot after·it had been running·for 1-1/2 hours. Heat = energy, and so I speculated that the CO2 sensor's heater·draws a lot of amperage (electrial energy, or "battery power".) Check it·out. I think it's in the CO2 sensor's documentation sheet.·Last year the ASP-1 was running inside the rocket for nearly 30 minutes before the rocket left the launch pad. The ASP descended slowly for over 26 minutes, then·we had to track it with a GPS/ short wave tracking device, then locate it. Total elapsed time from power-up (turning·the ASP·on) to power-down (turning it off) was well over an hour... and the ASP-1 was relatively easy to locate on the desert floor, and it didn't have a CO2 sensor heater.
For·"safety" (so we don't lose data, the ASP, etc.)·we must be sure that·our battery stores at least twice the amp-hours we think we might need. Three times the amount needed would be even better. That's why, when the ASP-2 is wired, programmed, and fully operational, we'll "bench-test" it. That means we'll power it up and let it run and run and run, on battery power, so we can be certain that we have·sufficient power (in case it takes a long time to launch or to locate on the desert floor.)
We can also measure how much·amperage each device draws and then calcualte how long the battery should last. Typically aerospace engineers do both: they calculate the required amperage (first), then bench test the device to see if their calculations are accurate. Then they add a "safety margin" of extra amperage 'just in case.' NASA also uses a 'redundant' system. They include two or even three batteries, connected separately, just in case one--or two--fail.·Also, data is usually stored as·"non-volatile data." That means if power is lost, data isn't. The data is safely stored somewhere (on a flash drive, etc.) "Volatile data" is data that geos away when power is lost... not a good idea!
ROCKETEERS --->
GIVEN: Our battery is a rechargeable 9.2 volt, 5,000 mAH Ni-Cd (nickle-cadmium) battery.
QUESTION:·Will our battery be "dependable" enough for the mission we have planned? Yes, or no? Defend your answer with facts and details, not vague speculation·or science fiction. If you're not certain, write a simple plan explaining how we can/should find out. ·
From DC,
Mr. Kibler
(PS to Justin): It's Mr.·KIBLER, not "Killer"... see you last e-mail!) ··
1) The battery below is 7.2 volts, not 9.2 volts.
2) The battery below is not nickel-cadmium (nicd, or "Nicad") It's Ni-Mh. What in the world is Ni-Mh...?
Well, to answer your ,"reliable battery" question, we would need to know 3 things.
1.) What is the total Amp drainage of the current ASP build?
2.) What is the combined Voltage requirement of the current ASP build?
3.) What are some Voltage limits of some of the components on the current ASP build? With the one you had last year, some resistors could of been optional due to the amount of power the battery supplied not being over the limit. With a possibly higher voltage on this battery, some resistors/potentiometers could be needed.
If we can factor this all in then look at the battery you posted we could find out if this is a, "reliable" battery. I do not have the specs of the ASP-2, restricting me of answering in sure terms. Or is this a question that can be answered more easily? If I am mistaken, please someone guide me into the correct direction.
Dylan Landry
Ni-Mh:
"NiMH" redirects here. For other uses, see NIMH (disambiguation).
Nickel-metal hydride battery
Modern, high capacity NiMH rechargeable cells
Energy/weight 30–80 W·h/kg
Energy/size 140–300 W·h/L
Power/weight 250–1000 W/kg
Charge/discharge efficiency 66%
Energy/consumer-price 2.75 W·h/US$
Self-discharge rate 30%/month (temperature dependent)
Time durability Citation Needed
Cycle durability 500–1,000
Nominal cell voltage 1.2 V
A nickel-metal hydride cell, abbreviated NiMH, is a type of secondary electrochemical cell similar to the nickel-cadmium cell. The NiMH battery uses a hydrogen-absorbing alloy for the negative electrode instead of cadmium. As in NiCd cells, the positive electrode is nickel oxyhydroxide (NiOOH). A NiMH battery can have two to three times the capacity of an equivalent size nickel-cadmium battery. However, compared to the lithium-ion cell, the volumetric energy density is lower and self-discharge is higher. (Compare: low self-discharge NiMH battery)
Disassembled NiMH AA cell:
1 - Positive terminal
2 - Outer metal casing (also negative terminal)
3 - Positive electrode
4 - Negative electrode with current collector (metal grid, connected to metal casing)
5 - Separator (between electrodes).Common AA cells (penlight-size) NiMH batteries have nominal charge capacities (C) ranging from 1100 mA·h to 2900 mA·h at 1.2 V, usually measured at a discharge rate of 0.2×C per hour. Useful discharge capacity is a decreasing function of the discharge rate, but up to a rate of around 1×C (full discharge in one hour), it does not differ significantly from the nominal capacity.
The specific energy density for NiMH material is approximately 70 W·h/kg (250 kJ/kg), compared to 40–60 W·h/kg for the more common nickel-cadmium, or 100-160 W·h/kg for Li-ion. NiMH has a volumetric energy density of about 300 W·h/L (1080 MJ/m³), significantly better than nickel-cadmium at 50–150 Wh/L, and about the same as Li-ion at 250-360 W·h/L.
-Wikipedia http://en.wikipedia.org/wiki/Nickel_metal_hydride_battery
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"Learn to obey before you command."
-Solon
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"Learn to obey before you command."
-Solon
Dylan, you could look at the documentation sheets for each of the parts on the ASP. See what each requires for amperage and then do the math. For example, if the total amperage "draw" (usage) for all the parts happened to be 1000 mA, and if the battery is a 5000 mAH battery, then it should run the ASP-2 for 5 hours. But I don't think the ASP will draw nearly that much amperage each hour, even with the CO2 sensor's heater going.
Dr. Allen and Sylvie, and I am the right track here? Can you help clarify power useage requirements to the Rocketeers?
Thanks,
Mark