I completed the kit, although when I put it in the light, only the right motor would function. I tried adjusting the trim pot on the bottom, but to no avail. I tried retouching all the solder joints, and it appeared to function properly when I put it very near a light, but the next day, when I tried it out in sunlight, in was going in circles again, except the issue was with the left motor again. So, I took it in, removed the touch sensors to make it easier to diagnose, and touched each solder joint once more with the soldering iron, and tried it again. Same problem, but only the right motor is going now. Although now if I cover up the left photodiode all the way, the left motor will turn, but not nearly as well as the right motor.
I’ve tried turning the trim pot on the robot, but I have no idea which way to turn it or how much. The instructions that come with the robot say to turn it “towards” the motor that’s not running fast enough. But towards it when the robot is right side up, or when it’s upside down so I can see the trim pot properly? I also read about turning it “all the way” one way or the other to test, but there is no “all the way”. It just turns freely with no resistance, as many times around as you like. And, no matter how much I turn it or in what direction, it doesn’t seem to change anything.
So, I don’t know if the trimpot is malfunctioning, or if the photodiode is malfunctioning, or if it’s something else. Any help would be appreciated.
I’ve tried turning the trim pot on the robot, but I have no idea which way to turn it or how much.
It’s a 20 turn trimpot so you can very accurately tune the beasty. Start by turning the trimpot 20 full rotations in one direction (you pick), then go back 10 turns - this gets you in the ballpark. There isn’t an endstop in these trimpots, so there is no easy way to tell when you have hit the end, unless if you use a multimeter to read the resistance between the middle and one of the side legs.
The instructions that come with the robot say to turn it “towards” the motor that’s not running fast enough. But towards it when the robot is right side up, or when it’s upside down so I can see the trim pot properly?
That would be when it is sitting properly, pointed away from you. So if in this arrangement if the PhotoPopper is not turning left enough, turn the trimpot counter-clockwise.
Hope that helps!
Dave (@ Solarbotics)
Hi BobSmith,
Welcome to the RobotShop Forum. You have already likely gone through the troubleshooting in the manual for this specific issue, though for other users who may see this post, here it is:
Only one side works:
When only one side works, you can compare it against the side that is working:
- Motor hooked up to pads “M-Blue” & “M-Red”?
- Solder bridge from motor pad “M2” to resistor pad? (left motor only)
- Trim pot adjustment turned all the way over to one side?
- There’s a bridge across the sensor pin pad to the spring pad
- The connection pads on the solar cell may be touching a part of the circuit board below it
We have contacted the manufacturer who may be able to shed some additional light. In the meantime, double check that no solder has run off and may be causing a short circuit.
