What could you use this for? It's a two channel, RC controlled digital pot.

W9GFO

I initially made this board just for myself, it is used to replace the joystick on an electric wheelchair controller so that I can roboticize it. It can either be hooked up to an RC receiver or a microcontroller.





It has two RC inputs and two digital pots. Each digital pot is 10k and has 256 steps. As a safety, if it goes for half a second without receiving a valid pulse it sets the pots to mid scale. So a microcontroller would only need to update the pulse three times a second for solid operation. Although faster would be better for smooth control.

I'm wondering if I should make some boards and put this on GadgetGangster. Can you think of any uses for it?

sam_sam_sam

What is the chip # for both chips

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·Now wanting to learn Spin· Thanks for any··that you may have and all of your time finding them

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Sam

John R.

If current capacity where high enough (or there was an easy way to add a high(er) capacity transistor, FET, etc, it could be used for a two chanel ESC for smallish motors.

Also, R/C light dimmers, remote display of an analog signal on a metter, adjustable zapping voltage for a dog collar (see the Marathon thread).

I'm sure guys in the lighting and stage prop (as opposed to Parallax Prop) would have hundreds of uses.

Lost of potential uses, but in some/many cases, the board, as it exists, may not be a "complete" solution.

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John R.
Click here to see my Nomad Build Log

W9GFO

It uses a PIC12F683 and a MCP42010.

The curent capacity of the pots is quite low, only 1 ma.

The only thing that I can think of where it is a "complete" solution is a replacement pot for electric scooter/wheelchair motor controllers. It could replace the throttle or joystick so that it could be turned into a robot or RC controlled vehicle.

Sisco

I know this is an old thread, but I am very interested in more details on this project. I read where you stated...

W9GFO wrote:

I have used a digital pot to replace the joystick on an Invacare electric wheel chair. The joystick that I replaced had four wires and was of the type that uses potentiometers.

Can you explain how this would be used?

I have two wheelchairs that I would like to use in a couple projects.

Both chairs are Invacare Pronto. I think one is the M51 and one is the M71. Both use the same joystick and controller.

Joystick = MK5 SPJ+
Controller = DK-PMA02 MK 5 NX

They use 4 conductors jacks.

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Here are some images (not mine) of the items I have..

Joystick..

Plug..

Controller..

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My understanding, if I am correct, is that the circuit you created was designed to plug into the current controllers four wire plug and to bypass the joystick completely, so that I could connect an R/C receiver right to the circuit board?

Rick

W9GFO

Sisco wrote: »

My understanding, if I am correct, is that the circuit you created was designed to plug into the current controllers four wire plug and to bypass the joystick completely, so that I could connect an R/C receiver right to the circuit board?

Rick

Not quite. It is meant to take place of the joystick only - and by that I don't mean the thing with the buttons and lights on it - just the part you steer with. You would need to open up the joystick controller (the thing you have labeled as "joystick" in your first image), remove the joystick and wire the digital pot in it's place.

This is an example of a joystick;

Sisco

W9GFO wrote: »

Not quite. It is meant to take place of the joystick only - and by that I don't mean the thing with the buttons and lights on it - just the part you steer with. You would need to open up the joystick controller (the thing you have labeled as "joystick" in your first image), remove the joystick and wire the digital pot in it's place.

This is an example of a joystick;

Ok, I understand. I would still need the original joystick controller electronics in order to turn the electric wheelchair on and off.

I have just a couple more questions, if you don't mind...

Does the above circuit board control direction only, or would it proportionally control the speed based on how far the stick is advanced?.

I realize, by the designation letters, that RC1 and RC2 connect via servo wires to the R/C receiver (or a microcontroller), but how would P1 and P2 connect to the joystick controller board.

I really appreciate your time in answering my questions.

Rick

Mike Green

It depends on the specifics of the joystick and joystick controller. For example, what's the maximum and minimum resistance of the joystick? What kind of connector does it use? How's it connected to its connector?

The middle pin of the pot connector is connected to the wiper and the other pins are connected to the ends of the pot ... there's a fixed 10K resistance between the end pins and the center pin is connected to an electronic "wiper" somewhere between the two end connections.

Sisco

Mike Green wrote: »

It depends on the specifics of the joystick and joystick controller. For example, what's the maximum and minimum resistance of the joystick? What kind of connector does it use? How's it connected to its connector?

The middle pin of the pot connector is connected to the wiper and the other pins are connected to the ends of the pot ... there's a fixed 10K resistance between the end pins and the center pin is connected to an electronic "wiper" somewhere between the two end connections.

Ok, got it. Thanks

Rick

kf5toq

I know this is an old thread but I have a couple questions, are these being sold anywhere, I want one. If not, I'd like to copy it for personal use but have no clue how to program it, I can handle the hardware side of things, and with a little direction can fiqure out the software side. Can someone tell me what other options are available for control of a wheelchair controller, other than complete replacement. This is what I'm looking for, just haven't found my answers yet.

W9GFO

I do not sell them but I could part with one of my boards if you think you could really use it. You would need to get the components separately, I don't know if I have any more of the chips.

kf5toq

That would be great, I've already located a source for the components, my main concern is writing code for the 12f683, I've never wrote any code, I'm certain I can handle the hardware side, if you could recommend a beginners programming tool and software.

73's
KF5TOQ
Randy Barbee

kf5toq

first let me say I'm not asking to be spoon fed but I have a few questions, if you was to do this project again would you continue to use the 12f683 or would you go a different route? did you read PWM for each channel or the ppm? I understand that I would only need 1 pin to get all 8 channels if i go with PPM. What is the best language to program the 12F683? because I've never programed before I bought an Arduino and started learning it, I'm not sure if its the best route but I figured I needed to start somewhere and it was available local and fast., I've also ordered all the components for your circuit, so the only thing left is to etch a PCB and build it. Any advise would be greatly appreciated.

W9GFO

You can read all channels from a single pin via the ppm signal, but you need to gain access to that signal either by hacking or using a receiver that provides it - none of mine do, I have not done that. I read the channels separately.

I programmed the PICs using PIC Basic Pro. It is very similar to PBasic, which is what the Basic Stamp uses.

kf5toq

thanks for the reply I've done a lot of research and doing my best to learn this Ive got a Turnigy 9x and even though I don't need all the channels now, I'm thinking about the future. I've already learned how to get the ppm signal. And honestly I haven't used BASIC since the mid-late 80's, what I knew then and how it works now is probably completely different.and is probably nothing like basic, I'm CompTia A+, ASE Master Tech in automotive, Studied but never tested(but would pass) for MCSE, have my General Ticket in Ham, President of our emergency amateur radio club for my county, work as mechanic daily, have worked CATV and Phones, network, cabling, alarms... for what seems to be forever, I've built a few remote controlled thingslike an rc mower and entry gate, but all were relay controlled or servo controlled and required no programing. Would the propeller be better?

W9GFO

kf5toq wrote: »

Would the propeller be better?

Yes, but way overkill for this application. All you are doing is reading PWM then outputting a serial string to the digital pot. But if you want to learn to program the Propeller this could be a good starting point, and you may find other interesting applications for it.

kf5toq

I don't suppose you would share your code for this would you?

drutledge

W9GFO wrote: »

It uses a PIC12F683 and a MCP42010.
The only thing that I can think of where it is a "complete" solution is a replacement pot for electric scooter/wheelchair motor controllers. It could replace the throttle or joystick so that it could be turned into a robot or RC controlled vehicle.

I think this is exactly what I'm looking for. I've been searching for "RC controlled pot" and coming up empty.

I want to remotely control the throttle signal 0 - 5V going into my motorized cupcake's motor controller. Your RC Pot would do the trick I think.

Do you have any on hand you'd be willing to part with?

paulos

Hello guys I know my question is out of context. but could you help to direct me who can build the board in the picture. Many thx

fthomson

Hi,

I was wondering if you have any of the circuit boards you would be willing to part with?