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Gimbal project – part II

So printing it is! Actually it all became a bit messy as I needed to do multiple iterations – practically on everything. That said – the code itself for this gimbal – spans over 560 lines and is becoming quite difficult to read.

Let’s cover just its basics. Code comes with the rendering options like below, allowing me to work on each part separately and also render each individual part for STL export.

// ************************************
// Output Renders
// ************************************
// 0 - all
// 1 - seat
// 2 - propeler
// 3 - main_ring
// 4 - fork
// 5 - axle
// 6 - stand
// 7 - plug
// 8 - video

I’ve tried to have code self-describing where possible, but ran several times out of ideas on how to name the actual part. I think that module named chicken_leg_stand() says it all. Anyway, let’s go through some of those parts.

Motor seat

I’ve taken this from previous models and just adjusted to be as flat as possible + moved the “floor” bit up to fit smaller motor. Printing it with bed-level support works out reasonably well, but tubes look strange from below. Still, it does the job.

The main ring

While it looks simple it took me a while to design all the holes to fit in the motor seat and even longer to fit in the servo lever (that black thing with a dot in a middle). Important thing here is that that servo lever has to be “submerged” in the ring material to the point where it is not interfering with the propeller and it holds strong enough to be able to twist whole that ring even when dealing with a spinning propeller.

Fork

Multiple challenges here. For needs to be precise size to allow good control of the ring , not smaller, not bigger – and allowing smooth 360 spin. Another problem was how to connect it to the axle – mainly without some super-complex trick. I’ve picked a simple cubic cutout + circle and squashed both a bit into a diamond-shape. Regarding the servo seat – I’ve reused the one we already had for a previous project.

Main Axle

The smaller the part gets – more time it takes to design it. This little monster was originally a part of the “fork”, but I somehow struggled to print it. Discussing this with Andrew he suggested separating it in two pieces – and it worked out. Except there was that new challenge to connect both pieces together.

Anyway – again a level shaft was needed, including an opening to install it. The master piece is in a circular-central maintenance shaft, allowing to use screw-driver to screw that lever in properly. I really like it.

Stand

What to say here – I needed something where we can start testing and it will be at least semi-stable. Great inspiration here was Andrew’s display – so all that round bottom part – that’s it. I’ve been also facing a problem to anchor the axle properly and came with some sort of guillotine mechanism to do so. I suppose I could spend more time to make it nicer, but didn’t as it is intended for testing only.

The plug

The last & smallest part – to fix the axle in the stand. It still takes 10 minutes to print this 1cm bit – incredible.

Now, if you’ve been brave enough to read it all the way, here is how Sebi hooked it all together with servos and his Arduino MEGA.

The best bit at the end – it really works! Enjoy!

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