We use these for counting the revolutions of our motor. We mount them to the output shaft of the gearbox with a piece of surgical tubing. One of our mentors manufactured some spiffy plastic mounts that strap onto the side of the motor to hold the potentiometer. Works pretty nice.
http://www.alliedelec.com/search/productdetail.aspx?SKU=9700063
Do you know what the deadband on that is? (How much space is there between when it hits the bottom and when it starts again at the top?)
Could we get a picture of these?
It’s in the specs on that page (electrical rotation 340 degrees +/- 3)
Hey everyone. Here is detailed shots, as well as a shot giving dimentions, of the POT holder for the 2.5" CIM motor. Sorry I can’t find my CAD drawing. Might of went with my computer when I had it wiped.
http://doug.devicariis.org/images/robotics/
I am sure one of you guys could recreate it in no time. I have been busy, or else I would. Have fun!!
Quick question and I dont want to start a thread about it. Do potentiometers have to be reset at all some way? Ive been tinkering with code and simply using the AnalogChannel->GetVoltage() and printing it to the console gives a voltage reading somewhere around ~30,000,000 which I assume means it isnt hooked up. No one has touched it since competition season and the potentiometer was fine since the last competition.
It is plugged into port 2 on an analog module.
What format string are you using when you print the value? The GetVoltage() function returns a float. You might have accidentally tried to print it as an int instead.
That might be the problem… Im retrieving it to a double value.
And Im printing to int. Honestly I dont know how to print anything but int. Just getting to know this stuff.
Here’s the VEX potentiometer we used for our arm position:
http://www.vexrobotics.com/products/accessories/sensors/276-2216.html
It worked well once we had a completed gripper on the end of the arm that worked… 
Sorry but our potentiometer is still not working. Potentiometer is hooked up to Analog Channel #2. Power is going to the analog module.
Code for printing is as follows:
(Im typing it because its on a different computer.)
AnalogChannel *m_Pot;
///////////////////////////
m_Pot = new AnalogChannel(2);
///////////////////////////
if (m_gamepad1->GetButton07() == 1){
m_LCD->Printf(DriverStationLCD::kUser_Line3,1,"v: %4f",m_Pot->GetVoltage());
m_LCD->UpdateLCD();
Driver Station is reading a constantly changing value ~0.003 that is sometimes negative.
How exactly is it connected? There should be three wires. Where does each of them go?
When you measure the voltage with a meter, does it do what you expect?
Not in the room atm but I’m sure that all three wires are connected to a pwm which then feeds into the analog module. It hasnt been changed (or at least not that I know of because OCCRA happened and fuses/pwms were taken off of the robot.) since last competition.
Colin,
Assuming that the code is functional, the reading sounds like what I would expect with a shorted wire. Use a voltmeter and check at both the pot and the wiring entry to the analog module.
Facepalm once again on our team the fault is not programming it is electrical. The solder holding the positive wire to the potentiometer broke off.
Only noticed after trying to stick a volt meter down there…:rolleyes:
Thanks for the help nonetheless as it did help solve our problem. 