Getting more throttle resolution from an old RC Controller.

I have been flying my tricopter around lately, and getting a bit better at not running it in to things. But one thing in particular has been bugging me about the controller that I have. The throttle stick resolution seemed really low, especially when compared to a friends, much newer and nicer controller. When flying it around at the Makery there was about one notch of difference between it barely skidding around the floor, and heading straight to the ceiling.

So, tonight I took it apart to see what I could do about getting a bit finer control out of it.  Turns out there is just a small spring arm with a bump at the end riding on notches molded on the back of the joystick. I believe this is pretty standard from what Ive seen online.

This is one of the times where having a 3D printer, and knowing a bit of how it works pays off. I need a very specialized piece with a bunch of notches running up a curved surface. This immediately reminds me of the surface that 3D printers make as lay down each layer of an object. So I take a few measurements, fire up the 3D modeling software and make a “cap” that will sit on top the current notches, so that the spring rids on it instead. You will notice that the 3D model has a perfectly smooth surface, but we get the ridges that it needs by setting the layer height for the printer.  I measured the old notches at .5mm on center, so I set the layer height to .3mm for  the first try.

After trying to print one by itself, and having it end up all blobby and malformed, I remembered to turn the “cool” setting on in Slic3r,  and put 5 of them on a plate to make sure they have time to cool between layers. I also turned the fan on, which I believe is why they all came detached from the build platform halfway thru the print. After turning that off and trying it again, 3 out of the 5 finished properly, and I was able to test it out. It worked great! It press fit right over the top of the old piece and the spring lined up perfectly on top.

It tested out to be a great improvement over the original. The ridges were smaller and more rounded, which gave it a lighter feel, but the spring was compressed more, so it still felt like it was strong enough to hold position. And most importantly It had better resolution, and I can fly it around without worrying so much about it running into the ceiling while indoors.

All in all it took about an hour from idea to finished. I would say it’s definitely worth trying this if your controller is like mine.

 

 

~ by rspoon on April 23, 2012.

3 Responses to “Getting more throttle resolution from an old RC Controller.”

  1. should have just made it smooth. Smooth would give you unlimited “resolution”

  2. nice work on this! what i did on my HK remote was slip a piece of surgical tubing over the click pad, made it feel more like analog resolution. Feels very nice to use.

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