Potentiometer

[Battlestar]

Hello folks. I came across this site a few nonths ago and was inspired by what I found here. I decided to try and make a motion platform. I have some building skills but unfortunately no knowledge of electronics. This would be made by copying what other people have done and asking endless questions. I have started with a GTOmega racing rig which includes a racing seat (http://www.gtomegaracing.com/). My welding isn't good enough to make a frame from scratch. I intend to use wiper motors for actuators and the "Velleman 110M" interface board in conjunction with a "Sabertooth 2x12" board for control. If I understand correctly from what I've read on the forum, I need a Potentiometer (or is it 2) for platform position data feedback. My question is what size of pot, what kind will I need and how is the best way to position it? I hope this isn't a stupid question, but I can't find the answer in the forum.
Thanks in anticipation. Mike

[motiondave]

Hello Mike and welcome, for control boards, may I suggest the Pololu JRK 12v12 http://www.pololu.com/catalog/product/1393 , one per motor, 7 wires, no code to write, one usb cable , simple uso commands, and they will handle 30 amps continuous with heatsink and fan cooling.
Ok the potentiometer is needed, one per motor to "tell" the control board "where" the motor is, so when the motor gets its next command, the pot supplies feedback to allow it to get to that point.
A single turn pot is fine, usually 5k linear pot is sufficient and cheap. Multiturns are good but expensive. Start with single turns first. I did and still use them on another frame I have.
For pot connection refer to these photos.
using a cut out lever so the lever "slides" with the bolt but moving the pot.
2 levers moving the pot.
gears on a multiturn.
Your frame could be mounted on a another frame with a pivot point under the seat at the right balance point. As you are planning to use wipers, you can mount them underneath, but as far away from the pivot point as possible, depending on the weight of the frame you have. Also at the back with levers connecting to shoulders is the best overall for leverage.
And by the way, my welding was lousy to begin with and I still have off days, but it holds!
Any more questions, just fire away.
Cheers, David.

[Battlestar]

Hi David,
Thanks for your reply. This is exactly what I was looking for. Now I'll have to get the pots and manufacture the connections. I appreciate your offer of assistance and will probably have loads more questions as I proceed.
Thanks again. Mike

[ferslash]

About potentiometers:

Yesterday i had a bad day connecting my pots, i was trying a new solution dad din't work, i will use a "clasic aprouch" i just have a question, is there any know problem using slider potentiometers??? because, as far as i see, everyone use pot (the rounded ones)

best regards

fer

[motiondave]

About potentiometers:

Yesterday i had a bad day connecting my pots, i was trying a new solution dad din't work, i will use a "clasic aprouch" i just have a question, is there any know problem using slider potentiometers??? because, as far as i see, everyone use pot (the rounded ones)

best regards

fer

got a sketch of how you plan to set it up?

[ferslash]

About potentiometers:

got a sketch of how you plan to set it up?

i was trying to directly connect the pots to the wipper motor shaft, so i made a hole in the motor and glued a screw into the motor shaft, then glued the screw to a pot... but it was a mess.

i will use the clasic aprouch like the one posted in this topic

the one that comunicate the pot to the motor using a holed ruler (i was trying to post an image but i got a server error)

[ferslash]

I have successfully connected a pot directly to the output of a big worm gear,

it is a lot to ask, but... do you have a picture

yesterday i tryied the holed ruler and i got success only in one pot, the other got brocke -this is the second i brake- (i am a terrible mecanic god!!!)

best regards

fer