Question on 3-D Clinostat Experiment

[Esperanzacs]

I created the 3-D clinostat using my arduino kit but the potentiometer does not seem to function properly. Is there any way I can alter the code and apparatus to remove the potentiometer, since this seems to be my main issue? I am also have issues with the code to decrease the rpm. Could I receive guidance on how to resolve these two main issues?

[Administrator note: Project url: https://www.sciencebuddies.org/science- ... -clinostat ]

[bfinio]

Hi - we will need more details to help us figure this out. Could you please:

- Explain what exactly you mean by "the potentiometer does not seem to function properly"? Does the motor spin at a constant speed regardless of what you do with the potentiometer?
- Similarly, can you elaborate on what you mean by "issues with the code to decrease the rpm"? What exactly is happening?
- Upload/attach pictures of your circuit so we can make sure everything is wired properly
- Upload/attach a screenshot of your code

Thanks,

Ben

[Esperanzacs]

Attached is my setup with the same code uploaded as shown in the setup directions. The end goal is to have 5-10 rpm switching directions every 1 minute. Would that be possible without the potentiometer?

[bfinio]

Hi - a few things:

1. I can only see two metal pins on your potentiometer, inserted into breadboard rows 20 and 22. Is there a third metal pin on the bottom of your potentiometer, and is it going into row 21 on the LEFT side of the breadboard (column e)? The breadboard rows are not connected across the gap in the middle - so if it is going into row 21 on the RIGHT side of the breadboard (column f), then it is not electrically connected to the green jumper wire going to pin A0, and the Arduino isn't reading the potentiometer at all. IF that's the case, you could fix this by moving the green jumper wire to hole h21, i21, or j21 and it should work.

2. All that being said, all the potentiometer does is let you adjust the speed while the motor is spinning without having to re-upload the code each time to change the speed. If you don't want to use the potentiometer at all and just want to hard-code a certain speed, or alternating between two constant speeds at a fixed time interval as you've suggested, you could do that. We won't write the code to do that for you - if you haven't already, we would recommend going through the first 7 tutorial videos on our Arduino page: https://www.sciencebuddies.org/science- ... an-arduino along with video 11 on continuous rotation servo motors.

3. A heads up: some students have reported issues with this project where the cheap plastic servos are burning out with continuous use. It may be a good idea to add some short pauses (e.g. rotate for 1 second, pause for 1 second) to allow the motor to stay cooler and decrease the risk of overheating.