rechargeable battery on board? I have access 2intermittent power @ a mechanica

weezer

Hi Everyone,· I am really enjoying learning stamp working from reading the vast prior discussions.· I am an artist and have a robotic piece that spins around on a bearing made out of a VCR head with a two track "motor brush" style power feed.· It is 12V and runs a bunch of motors, and a car antenna device which I have rigged to do something else.· It appears to feed power continuously, but even with a second pair of brushes, I think there are imperceptibly brief interruptions, which cause the stamp to be in a constant state of reset.· So I have a 9v battery which can drive a couple relays and the stamp, but I need to ship this thing to an out of state show.· Ideally I need·a circuit to trickle charge the 9v, so it is always engaged, but I dont really understand this kind of electronics, and most circuits seem to require everything else be disconnected to charge.· I won't be there and the curator or registrar will definitely not change batteries for me.

Does anyone have an idea?

The transister driver idea already saved my bacon on the relay.· Thanks again for an active and informative forum.

Randy Polumbo
randy@3-dcon.com
www.polumbo.com

KenM

First question is what kind of 9v battery is it?

The type you purchase at about any drug store, gas station or grocery store? To my knowledge those are not rechargeable.

Do you have a schematic of your circuit you can post?

weezer

Ken, thanks for your reply. I was assuming I would by probably a small 12v rechargable cel, since I have 12v on board.· The stamp is a bs1, the inline ·one, that slips into the slot on the very small accessory board.· There is not much of a schematic basically my problem exists between the intermittant power, and the stamp/battery part.· Everything works fine, the relays fire, the motors all do their job.· I just need a way to trickle charge the battery ALL THE TIME, so when the piece spins around (typically anywhere from 5-50 rpm) it does not lose power to the stamp and stop running the lengthy relay control program that makes the motors do there thing.

Any idea?

thanks R

SPENCE

If it is not going to be moveing around i would sugest a "sure charge iv" charger from northern tool or the likes.

It is a pulse charger and helps to prevent deterioration of the rechargeable lead acid batteries. Have lead acid rechargeable batteries here still working 10 years later and in good shape.

73
spence
k4kep

weezer

Hi Ken,· Thanks.,· I guess having never been on here, I am not doing a good job of being clear.· i was hoping for a very small, or homegrown way to trickly charge.· I have 12V in, then it comes out into this moving apparrattus where I ave room for something the size of a pack of cigarrettes for all my circuitry, whcih is about half used up.· Isnt there some way to take some diodes and stuff and take the 12v and use it to trickle charge a lead acid gel cel that will feed just the stamp and its one relay it drives direct?

I assume if I just connect the 12V to the power with nothign in between the cel could blow up or something if it was plugged in too long.


Thanks R

and 73 ( KB2SDZ)

K de Jong

Hi,

Can't you just use a resistor from the 12 Volts to the 9 Volt battery ???? R-330 Ohm would give you about 10 mA charge current.

Regards,

Klaus

Bean

If the goal is just keep the BS1 from resetting, then a diode and memory backup capacitor would be all that's needed. Or am I missing somthing...
Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-Video Display Module" Available Now.

www.sxvm.com

"A problem well defined, is a problem·half solved."
·

weezer

Klaus,

That works for me if it works for you.· What if:

1.·the 9v battery is powering the stamp, as it is being charged?

2. the battery is being charged CONTINUALLY 24x7 including when there is no stamp running. won't it blow up after it is full?

Thanks R

weezer

Bean,· Your solution sounds elegantly simple and would probably cover the milisecond fault in the power, without the potential for acid and heavy metals to spew about if I somehow bungle the battery charger.· It certainly meets my space needs.· What diode and cap would you use?· And how to wire it?· The cap in parallel with the juice and diode with the arrow pointing towards the stamp on the + lead?· I am an artist, and the lamest of pretenders in electronic things, although I do seem to get things working after my fire, smoke burn in regimen.· (when fire and smoke stop coming out, I know I am done)

I don't understand how a capacitor can discharge over time. I just recall flipping the little ones at my brother after I charged them with·a 9v battery.· It helped him stay awake in 4th grade. [noparse]:)[/noparse]

THanks R

Jonb

Making a charge circuit can be tricky. You must know exactly what the battery chemistry requires(constant voltage, constant current, etc.). Once you've determined what the battery needs, you must design a circuit that stops charging when the battery is full. Some rechargeable batteries are very finicky about this and can actually burst into flames if charged incorrectly. Battery charge circuits can be found all over the web but they are battery dependant.

allanlane5

You might try simply adding a 10 to 40 uF electrolytic capacitor across the BS1's power supply -- with a diode if you want to guarantee the cap drives the BS1 only, but that's optional to start.

It sounds like the BS1's power is getting 'browned-out' (ie voltage lowered to the point where it resets the BS1) by the motors. The 'local' capacitor to the BS1 may reduce the impact of brief dips in the motor voltage.

weezer

Thanks Alan,· It is not the motors, it is this crazy thing I rigged that supplies 12vdc to the spinning apparattus by dragging salvaged motor brushes on circular bronze strips.· I put two pairs of brushes in the hopes that if they lifted or skipped, the other set would be in contact.· There is still enough interruptions in the power that the stamp stays in constant reset.

do you think your solution might work to address this?· If so where does the diode go, between the cap, and the stamp, on the positive.?

Thanks R

Bean

The cap connects directly to the BS supply and ground.
Then the diode with the arrow pointing towards the BS and cap, and the other end going to the supply.

Bean.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"SX-Video Display Module" Available Now.

www.sxvm.com

"A problem well defined, is a problem·half solved."
·

allanlane5

Yes, the purpose of the diode is to insure that current goes FROM power, INTO the capacitor and BS1, then FROM the capacitor, INTO the BS2. Thus the cap goes across the BS1 Vdd and Vss. The Diode feeds into the top of the Cap and Bs1. This creates a very simple rectifier charging circuit. It will definitely work if the BS1 is not pulling too much current from the Capacitor, or the Capacitor is large enough, or if the 'gaps' are short enough.

Tracy Allen

1N4001
--->|-----o-------  
              |
              | +
         =====  220uF, 16 volt or 25 volt
              |
              |
-----------o--------

On the left side input the noisy power from the brush system. On the right side, your Stamp. Keep the leads on the right short. The capacitor stores enough energy to keep the Stamp running during the brief interruptions in power during the time the brushes bounce. I don't think you need an additional battery.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Tracy Allen
www.emesystems.com

weezer

I will try this when I get home from my "day job" tonight. Thanks for all the help everyone. I am really impressed with the promptness and generosity of everyone's replies.

Best R

weezer

Thanks Everyone!! The Cap and Diode worked like a champ. If anyone wants to see the completed piece with its electronics overhauled, in a very primitive animation, please check out my website www.polumbo.com "Joey" is the name of the sculpture, and you mouse around the little pictograms until you see the "joey" title, click, and let it load. Bear in mind it rotates 360 near randomly and now that it is not on my version of direct drive artificial dumb intelligence with some relays and sensors, it seems to be more aware of what is going on in the room, which is impossible since it is reading my poorly scribed code from the BS1..

Thanks so much.

Randy

Paul Baker

Cool site Randy, interesting use of Flash's tweening operation. You may want to reduce the bounding box size of the index, can't read the title of your last few creations since the text is offscreen. Your creations remind me of a cross between Dan Flavin's light sculptures and Alexander Caulder's wire and mobile sculptures, though Im sure there are more contemporary artists which would be a better analogy. Do you ever get the desire to create things as grandiose as Tinguely's M

allanlane5

Unfortunately, I'm over 40. Otherwise I'd say something like "Oh MAN! I want to do what you do when I grow up!"

I've always wanted to build stuff out of metal and electronics that do stuff. It never occurred to me that this could really be art. I'm so glad that the diode and capacitor worked, now I can say I had a small input into something beautiful.

Note if you go to a BS2, the BS2 may reset more often. The BS1 is MUCH more tolerant of low-voltage power than the BS2 is.

weezer

·HI again,

I had the thing working again, and somehow I think I fried the BS1.· I am curious if running it at 13.8 volts is too high.· I tried adding the 330 Ohm R in series on the + and maybe I forgot ohms law, but it seems to still be at 13.8.· I have a new stamp in and it seems to be running, but I cannot figure out what fried the other one.· I have to ship this thing out of state for a show, and I dont mind if they have to reset it, but I will be sunk if I have to fly there and change the BS1 periodically.· Ouch.

Thanks R

PS Here is the animation if anyone wants to see it.· It is way oversimplified, the thing also rotates 360 both ways on air power and extends 5'

allanlane5

That's why people made a little something called a "Linear Regulator" -- oh, wait, the BS1 already HAS a linear regulator on it, right? Is it a SIGNAL that comes in at 13.8 volts? Or the power supply? If the power supply, adding a resistor is not a very good idea -- it will drop the voltage based on the amount of current used -- and the amount of current will vary quite a lot.

I haven't dealt with the BS1 yet, so you're out of the areas I know stuff about.

weezer

Thanks Allan, The power supply comes in at 13.8 because the piece uses mostly car type motors to run and a big car power supply. The replacement BS1 works fine with a 9v battery on it, and now oddly will not run at 13.8, but will run with the resistor but there is not enough juice to trigger the transistor circuit I found on here to trip the relay that makes everything do its thing.

Is there a smarter compact way to make 9-12 out of 13.8?

Thanks R

weezer

Alan, I found an old regulator circuit that I used to stick on a 9v battery on to make 5V and put in inline. It works for about 60 seconds, then says "stamp not found" and seems to be crashed beyond reset until I power it down and start over.

Shouldnt the stamp run on +5V? Excuse me if this is a really stupid question.

I ordered some of the regs you mentioned from DIGIKEY in the meantime.

Thanks R

allanlane5

What you want is a Linear Regulator. This acts like a very fast variable resistor. You need one that puts out a rock-solid 9 volts -- I don't know what part that is. We use 7805's for 5-volts, and LM2940-5 for 'low-drop-out' regulation. Google for those two part numbers -- I think the 2940 comes in other voltages.

Bruce Bates

Weezer -

The BS-1 can be powered from one of two pins, either Pin 1 or Pin 5. If you are supplying an unregulated voltage, or a voltage greater than 5.5 VDC, you use Pin 1 which will accept a range of voltages from 5.5 --> 15 VDC. If you have a regulated voltage between 4.5 --> 5.5 VDC you can apply that to Pin 5 instead. One or the other pin can be used, but not both.

The following is just an educated guess, but I suspect it may have some merit. I suspect you are going to say that you're using Pin 1 and have that connected to your battery, and in turn a battery charger is connected to the battery. I further suspect that when the battery charger comes online it may well be producing voltages in EXCESS of 15 VDC, therein blowing the regulator on the Stamp. If that is the case, I'd place a 12 volt (approximate) Zener diode between the rechargable battery and the Stamp. This way the battery charger fully "sees" the battery and can charge it properly, but no voltage over 12 volts can reach the Stamp. Any Zener diode between 12 volts and 15 volts would work equally well if you're feeding Pin 1.

Parallax does offer a repair service for Stamps which have had their smoke let out

Regards,

Bruce Bates

weezer

I am not using a battery, I am using the capacitor & diode circuit further down the thread to keep the stamp from losing power.· Now I took this old voltage regular that works great on 9v batteries bringing them down to 5.5 for digital circuits.· I put it after the diode/capacitor, and it has a light, so I know I am not losing power at all.· I have no battery, and the power soource for the 13.8 is a big 3 amp car one from Radio Shack that seems very reliable 13.8.

Now even with the 5.5v coming in on pin 5 which works great, the stamp fires the relay once, and then crashes so it cannot be found by the editor again until I power down and disconnect everything.· I am wondering if there is noise or slop downstream in this car antenna apparattus motor or something else.· I have it neither rotating or running the propellors and it still bombs out.· This is the exact problem I had feeding 13.8 into the·VIN·pin, that I thought giving it steadier fuel would avoid.

Now I am thinking it may not be the power at all, but I don't see any shorts or issues.· When pin 6 which I·using to drive the relay goes hi it is only 3V.· Is this normal?· It just barely trips the relay with the·TIP transformer circuit elsewhere on here.· Can I isolate this better somehow since the stamp will run all day on the 13.8 or on the 5.5 until I connect the relay circuit.· It is enclosed except i used a TIP3 because I had one.

Thanks R

weezer

I just tested this with a fresh 9v battery powered the normal way for good luck, and now it is crashing after one relay cycle even with that. this ran for at least 6 hours before it fried the first BS1 that gave its life. I am very confused.

Thanks in advance for any thoughts, I am sorry this is proving to be such a troubled little mission. I thought I was done 3x already.

Thanks R

weezer

Hi Everyone, You can shoot me now. I just found an old homework board in my parts bin, and alligator clipped it in, and it works fine. SO don't spend any time on my Clueless laments above, although I would love to know why the BS1 would not work. I thought they were more robust, and they are cheap and little, which us artists like.

I wonder how the BS2 will like having the battery side 50% of the board cut off on my band saw.

Thanks R

weezer

I spoke too soon, the bs2 crashes as well, although it takes 10-15 min. and at least it restarts reliably from the button. Any ideas?