Pi Wars T-34: Attachment Part II

What's that? More CAD, more 3d printing, more forehead-smacks at making silly mistakes? It must be...

Making the attachments work

grabber

The arms for the barrel grabber are on about revision 4, after realising

1) I had mirrored the first arm, gear and all, to make the other - so when the gears meshed the arms were half a tooth (15 degrees) out of phase and wouldn't meet in the middle

2) The arm driven by the servo was backwards, and I couldn't just turn it upside down because the servo horn recess on one side meant it was chiral.

I was also having some problems with the servos jittering quite badly when they were meant to be holding a position. So, another round of CAD and printing, updating my code so it wasn't giving the servos a 100Hz PWM signal when they really want 50Hz, and adding an "off" button that would just stop the PWM signal to the servo which tends to make it deactivate. Now how do they look?

(Fun side note: I discovered that a Sainsbury's glass spice jar, of which I have several saved In Case They Came In Useful, are a close match for the 80x55mm dimensions of an Eco disaster barrel. Maybe I'll wrap some one in coloured paper to save me having to find red and green filament...)

- PKM