Testing (very important)

It is very important to test this project before actually using it. There are a few tests that I have been running while building it that allowed me to see if it was working. I made a really bad mistake by assuming that the stepper motor would work just the same with a reversed direction. Turns out I was wrong and ended up driving out to West Virginia to leave with a picture which, even though it looked pretty cool after putting it through stacking software, was not at all what I was looking for, and could have been attained with a camera on a simple tripod. I'm not sure why this didn't work, since my 3D printer uses the exact same stepper motors and they go in both directions, but regardless of the reasons behind it, just keep in mind that direction is very important.

projects_20200730-output.jpg
What happens when your tracker doesn't actually track

Movement test

This one is quite easy. Simply change the second, longer time.sleep to something really short. I used 0.005. This test is much easier to do if you have the camera plate mounted without the camera and weights, extending it like in the picture below. Then, copy the code to the microcontroller and watch it. First check the portion of the worm gear on the motor. If you can see the bolt on that moving around, then it's working. Then, check the camera plate itself. Look through one of the holes in the plate for a few seconds, and if you can see that it's moving, then everything should be working. Facing it, the plate should be moving clockwise, and from behind, it should be moving counter-clockwise.

If when you are testing the motor, it is clicking or vibrating, then move the wire in B2 to A1, B1 to A2, A1 to B2, and A2 to B1. With the TMC2226, there should be essentially no noise or vibration.

Tracking speed test

You want to make sure that at the tracking speed, the motor is smooth and going at the right speed. If your camera plate has any bubble levels, align one of them so it the bubble is in the middle. You can do this alignment by using the code from the previous step. Then, when the bubble level is parallel to the ground, copy the code with the delay set back to the delay for your gear ratio to the device. At this point, it is really helpful to set a stopwatch on your phone. After a few minutes, you should see that the bubble is no longer in the center. This means that the mount is moving. Now, you want to verify it's moving at around the right speed. This isn't super scientific, but it verifies that the tracking isn't way off. I printed out a clock and compared it with the camera plate every hour or so for six hours. If it started off at 12 o'clock, 6 hours later, it should be at 3. To make sure the clock is reasonably level, I held my phone to the top of the paper, using the built-in 'measure' app's level (I'm on iPhone, but I'm sure there's an Android equivalent that works just as well).

This guide was first published on Aug 06, 2020. It was last updated on Aug 06, 2020.

This page (Testing) was last updated on Oct 23, 2021.

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