I’m looking for your input on a project I’m working on (the Gopher)

Washer Medic

Hi all I’m looking for your input on a project I’m working on
I work on industrial laundry equipment one of the jobs we do is clean the lint that builds up in the ducts. I’m trying to get out of carrying the brushes and rods to the roof and then pushing and pulling it up and down from 1 to 6 stories while standing on a pinched roof The desired finished project would be able to climb a duct from inside with either a camera for inspection and or a rotating brush to nock the lint loose
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Some things to know most of the ducts I’m working with are round and start at 8” and progressively increase in size roughly 2” for every additional dryer and 2” for every 10’ of rise so it could end up being 36” at the roof with that in mind I built a prototype tractor /gopher that has 3 tracks placed at 180 120 degrees apart and will adjust its with as it climbs currently using vex motors and tracks that I added rubber to for traction but would like to find something better eventually
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Now what’s need is the controller to drive the system im thinking the control box would have an analog single direction joystick or pot for forward and reverse speed control a duel joystick for camera pan tilt An LCD display on off switch for the brush with a stamp sending info to a psc in the gopher unit the cameras, LCD and brush motor I currently have are 12Vdc
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OK I’M IN OVER MY HEAD AGAIN but im learning something new every day and that’s the main goal of this project any way. where I need your help
Question 1. Where do I find the analog joysticks the type that are used in hobby transmitters I tried google but only found porn sights or video game equipment or is their an better or different way
············· 2. I would like to limit the wires going to the gopher unit if I use 12vdc I would need to regulate it to 5vdc for the psc and 7.2vdc the servos to give me 1, ground 1,12v+ 1,pwm and 1,viedo cable is this the best way?
·············· 3. Does any one know where to find good rubber tracks I found every thing from ones to fit my skid loader to ones for an m1a1 Abrams tank but nothing like what im looking for?
·············· 4. Does any one have source for a good inexpensive color camera and LCD display preferably hard wired I don’t think rf will work with the metal
············· 5.Can i send pwm from the stamp to the psc 60' away?
Thank you for your time all comments good or bad will be very much appreacheated
Brian

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There's nothing a good wack with a hammer won't fix

Darn I let the white smoke out again

Post Edited (Washer Medic) : 11/17/2005 4:37:42 AM GMT

Rsadeika

This sounds like a pretty ambitious project, aside from wanting info for all the different parts, is this a functional 'gopher'. Meaning, do you have this prototype crawling inside of the duct work now? If yes, you may want to supply some information as to what is involved at this stage, in terms of controll of the prototype.

Jim Richey

That is a very interesting machine you are building.It looks very well thought out.Are the tracks spring loaded to maintain contact? Can't see in the photo.Guess you might try one thing at a time until you get it right.Maybe running it in a test pipe with simple DC forward/reverse ,hardwired,would get the debug process rolling.Would there be any real need to PWM the motors? If the servos are a concern,yes you can send them their control along a wire.Cameras are cheap,though some see better than others of course.Tracks are difficult to find as you see.I am using assemblies from a snowblower.

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Thanks, Parallax!

bulkhead

Interesting project.

1) You can get 2 toggle switches, attach one of them to the other (for a 4 way toggle), sort of like how its dont in hobby RC remotes. Or you could try and disassemble a console game controller-some of the newer ones (PS2,gamecube,xbox) probably use some type of encoding system (if tahts what its called, like using different pulse values to indicate which buttons are pressed, requiring only a few wires for the 20+ different buttons), but older controllers (like those for the sega genesis, maybe supernes) may have a simple 1 wire per button (switch) config, which you can easily just hook up the wires to an extension and to your stamp.

3) If you find any, please post here-I'm sure many are interested in these (at least I am)

4) Ebay. You can probably get a wireless "mini color camera" for $30. Just get a really long AV cable extension to eliminate the "wireless factor." Some camera bundles on Ebay are simply a wired camera plugged into a "video" signal transmitter, so you could just take off the transmitter and plug to an extension. You could use a laptop and USB video adapter for the screen, or maybe a cheap portable DVD player.

5) I believe it depends on the resistance of the wire- you can measure it and find out your current/voltage (im not sure) loss and (I dont know if you could do this but) make up for the loss accordingly.

Just curious-what are you using for a motor controller(s)?

Washer Medic

Hi thanks for your replies my original design was more like a pig all pneumatic where one blatter would inflate then a cylinder would push the second one up then it would inflate the first one would deflate then the cylinder would pull the lower one up but I
a banded this idea I was afraid some smart allic might have stuck a long screw in the pipe half way up that would either pop the blatter or worse yet get stuck on it
I’ll try to answer some questions as well as ask some more on my current design
Yes the tracks are spring loaded with the current setup I can go from an 8” pipe to a 14”pipe although I’m not satisfied with the wide range of differing tension produced from the springs would like to find a different method that would keep the same tension over a wider range of motion thought about active suspension but that would be later and then theirs the kiss principle to consider also the tracks im using are hard plastic that slip so I coated them with a latex product but it doesn’t last to long now im trying the stuff you dip tool handle’s in it seams to be sticking a lot better although its tough to apply
Currently using RC gear from my helicopter to test the gopher in the 8”fill pipe on the side of a silo but it doesn’t change in size and the RF signal doesn’t work well in the pipe
The VEX motors im using are just continues rotation servos I would have preferred to use the Parallax ones but didn’t know how or where to get gears ect for them and the way the Vex motors attach is handy I have several wire less cameras but I think ill have the same problem with them that I have with the rc gear so I’m looking at wired ones
The learning curve is a lot steeper then I originally imagined I went through the what’s a micro controller text and the concepts I have seam doable but there are a few things I need to understand a whole lot better my first hurdle is sending pwm from the stamp 60’ away to the psc this would control 3 drive motors fwd and reverse from a single joystick or pot pan and tilt from a duel joystick have not decided on the brush motor yet weather its just a continues rotation servo or a rc car motor with controller well back to my research though google is not being very friendly to me right now must not be asking the right questions

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There's nothing a good wack with a hammer won't fix

Darn I let the white smoke out again

Paul Baker

for analog joysticks, goto www.digikey.com and type joystick in the search dialog, then Potentiometers category.


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·1+1=10

Rsadeika

Trying not to be brutal, the 'gopher' is at a 38' level of duct work, and for whatever reason it is stuck, how do you get it out? Will it be possible to take apart duct work, and/or knock a wall down?·If you are running the 'gopher' with an umbilical cord, then do you roll in a 100' spool of cord, what if your cord and the 'gopher get entangled. Do you know all of the conditions of the duct work? The point I am getting at is, be prepared for the worst case scenario first, then proceed to the next level. Since you are in the business you probably have a good idea of what you will be dealing with, first take care of the obvious, then think about the attachments. Once you take care of the obivious, then you might be limited to the types of attachments you will want.

Seems to me like you have two problems that you have to deal with for the moment, 1, how do you get the 'gopher' out, and 2, how do you accomplish a clean transitoning within the duct work. By clean I mean going from 8" to 10" to 12" , ..., 36". Keeping in mind vertical, horizontal, angular, and any other weird configuration.

Post Edited (Rsadeika) : 11/18/2005 7:03:43 PM GMT

SN96

Very nice idea. Keep us posted.

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Mike



Post Edited (SN96) : 11/22/2005 1:43:29 PM GMT

Jim Richey

I wonder if you could use magnets in some way to provide the needed traction? Don't give up,you have a cool idea that will give you an education!

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Thanks, Parallax!

Longneck

Heating and Air Conditioning: Air Quality - A. Johnson Plumbing ...
... motorized brush/vacuum robot and remote ... video camera that travel through your ... Johnsons Plumbing, Heating and Air ...

www.yeswefixit.com/HVAC/hvac_air_quality.htm

Although I didn't see a picture of the robot on the site , these guys have a robot that cleans duct and makes before and after videos.....maybe if you e-mail em they might share some info.

Washer Medic

Hi thank you for the replies
Paul
the digikey info was very helpful im going to order a few shortly and try them out also I found an old Futaba pre 1990 rc transmitter I had laying around I might cannibalize the joysticks from that in the meantime
Rsadeika
I have little fear if the gopher gets stuck in my past life I was a building contractor in fact I built a few of the building’s we work in now so a little bit of spackle and drywall and its like new. Already had an incident 20’ in with a manual brush and my fiberglass push rod snapped ended up using an old window sash weight and a rope to get it out. Theo destroying a $60 brush wasn’t that bad compared to smashing a $1000 robot OUCH!! also I have other thoughts on how to deal with this the tether could be set up that when you pull it could release tension on the tracks making it easier to retrieve probably will run in to a few problems on the mechanical end but it’s the electronics end I need guidance on to proceed much farther
SN96
Shore will you will probably get tired of seeing me
Jim
I like the magnet idea just might look in to that a little and the education is the true goal I was able to troubleshoot and repair a $1600 proprietary computer board with the training from my Parallax scope
Longneck
Nice site

As for the gopher I’m trying to break every thing down into small systems see enclosed drawing comments and ideas will be appreciated
Brian

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There's nothing a good wack with a hammer won't fix

Darn I let the white smoke out again

Jim Richey

I can't seem to get the thought of attaching magnets to the tracks off my mind.If you don't try it,I will have to!

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Thanks, Parallax!

Jon Williams

I'm a little late to this discussion -- but here are a couple thoughts:

1. Why build your own joystick when you can go off-the-shelf?· You could use a Sony PlayStation analog controller and get two joysticks (granted, not great resolution) and 16 button inputs -- this would be useful for a robotic controller (in fact, that's the theme of my January N&V article that uses and SX [noparse][[/noparse]programmed in SX/B] to create a serial PSX interface).

2. Probably -- but you'll want to put a lot of filtering onto the 7.2 volt supply for the servos so that motor noise does not get back to the electronics.

3. I have no idea about tracks; you might check with robot clubs like the Dallas Personal Robotics Group (www.dprg.org) or Seattle Robotics Society (www.seattlerobotics.org).

4. Check with BG Micro or similar suppliers -- they carry those things.

5. The PSC takes a serial signal, not PWM; what you may want to do is use and RS-485 connection for distance and noise immunity.

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Jon Williams
Applications Engineer, Parallax

Rsadeika

Washer Medic,

Since Jon mentioned his new article, pertaining to joy sticks, it came to mind, that in the·Guenther Daubach book, he has an SX tech bot project which uses a joy stick and the SX tech board. The source code in the book is assembly, so that may not be the way you want go. I am not a 'bit banger', not for the SX anyway, but their are other people on the forum that are.

I assume that you have the electronics squared away for the VEX motors, so the next thing is how to control the joy stick for the videocam setup. I think that I remember glancing at a thread on this forum pertaining to somekind of swivel mechanism for just such a thing, I could be wrong, but you may want to do a search, and see if you find something.

At this point you may have to start considering what kind of processor you will be using, for your project, I/O availability may not yet be an issue. If I were you I would keep a close eye on that. If you start relying on a particular processor, and it falls short of expectations, then you may end up with, back to the drawing board.

One other issue that you have mentioned, the track system. I get the impression that you are not getting the necessary tension when you are at, let say 36" duct. Since you already mentioned a bladder system, you may want to investigate electro-pneumatics. It probably will not be an easy search, but you may find something along those lines in some of the specialty robot outfits.

Washer Medic

Hi Jim I played a little with the magnet idea over the weekend I used the type that’s used in refrigerator door gaskets I glued a few segments to a small piece of track then I was reminded that most of the inner pipe liners are stainless due to the high moisture content so I guess that idea will be put on hold for the moment but I will re visit at a later time let me know if you get a chance to try it you will probably need stronger magnets thou Was thought about a suction type device while helping with the milking on my friends Derry farm the other night but I’ll stick with my current design for the time being
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Jon thanks I didn’t mean to interrupt your vacation
I need to get a better understanding of programming the psc the docks just are not doing it for me can you suggest any books or articles that might help and the rs-485 as well I’m thinking I’m in way over my head at the moment but willing to learn just hope everyone has patience with my extreme learning curve
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Rsadeika ones and zeros are way over my abilities at the moment though I will be interested in Jon’s joystick article
Unfortunately I don’t have the electronics worked out at the moment I only have concepts on how I think it should go together
The pan tilt mechanics are fairly simple Parallax has them for the hex crawler
Thinking back to my old sewer camera I might not even need it if I get the right camera
I’m hoping I can do everything with a bs2 it won’t be an autonomies vehicle that will need a lot of programming ability just manual control just frying to limit the amount of wires going to gopher by using the stamp and psc
As for the tracks im concerned the vex tracks will not hold up they only snap together the traction has not bin a problem yet but won’t know until I get the electronics worked out and get a chance to test it better
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Thanks again for all the help I’ll be away for the holiday going to visit Mom in Florida but will be back to the project next week
Brian
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There's nothing a good wack with a hammer won't fix

Darn I let the white smoke out again

Jon Williams

What isn't the PSC documentation doing for you? Are you confused about implementing the commands that it uses, or are you wanting specifi servo-control application information for your project? You might want to consult the various robotics groups (www.dprg.org or www.seattlerobotics.org) for articles on combining servos for applications like yours.

As for RS-485, it's not that complicated -- check out Jan Axelson's book "Serial Port Complete."

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Jon Williams
Applications Engineer, Parallax

Washer Medic

Hi I’m finally getting caught up from the holidays and trying to spend some time on the project thought I’d start trying to work on some programming
well first hurdle Rc time reading a pot on the joystick. Yes it would probably be better to use the play station joystick as Jon recommended but I’m trying to use an old Futaba joystick it fits in my controller panel better. The pot on the Futaba joystick is marked 5 k referring back to the what’s a microcontroller text chapter 5 they use a 10k pot I would think that would not be a problem all I need to do is change the scaling is this correct.
Using the exercise ReadPotWithRcTime.bs2 on page 151 I ended up with a hi # of 209 and a lo # of 142 verses the 10k pot that has a hi # of 691 and a lo of 1 my question is using the formula’s on page 155 I get the fractional value of 418 but I don’t seam to be getting the proper servo rotation what am I doing wrong

thank you Brian

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There's nothing a good wack with a hammer won't fix

Darn I let the white smoke out again