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Quadro - a 3d printed quatropode - Part 2

 ·  ☕ 2 min read  ·  ✍️ TinHead

Intro

So to start with the positive thing:

Yup I’ve got it moving 😄 .. err.. -ish that is.

The good

Turns out the choices I have made for brains worked pretty well.
The Raspberry Pi Zero works great combined with the PCA9685 pwm driver.
I had all servos moving no problem.

The battery choice also good, it had enough juice to power both pi and servos without issues.

The bad

The design I did for the servo mounts all over were plain bad 😠
I had the impression that the output shafts of the servos would be able to take some pressure while attaching things to them (being metal and all).

Why? Because in these servos the output shaft is connected directly to the pot shaft. You push down too hard pot moves out of it’s place and the gears stop meshing.

What’s even worse is that the pot gets decalibrated so your servo will never be working properly unless you manage to put back the pot in it’s original position and you are lucky enough it did not get damaged.
So if you use cheap servos don’t force anything on the shaft use the servo arms in your design.
There lesson learned, now I have a huge amount of servos to use as plain geared motors.

The ugly

But the bad above wasn’t the only problem.
Here comes the ugly:

  • My original design ideea relied on the mounts I have designed for the servos - to fix besides new servos I need to rethink the whole thing
  • Jitter in the servos - I’m not sure if that was caused by the treatment I did to them or the code but sometimes they would go crazy - probably both 😄

End

This project is on hold for indefinite time due to other higher priorities - like moving outs.

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TinHead
WRITTEN BY
TinHead
Linux guy, friendly hacker, 3d printer lover

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