Itchy Motor Driver Failure

So, picoFarads are not the same as microFarads.

I was reading a data sheet on my phone and the mu looked enough like a p that I put in the wrong capacitor. I might already have burned it out before that, although I think the power supply was regulated and it should have been fine – but once I turned the power on properly and had everything at the right levels… the 11v line kept trending downwards. The motor power supply was grounding. The magic smoke had escaped.

I needed to check that I hadn’t burned out the motors, which I did by checking their resistance. At about 3 Ohms, that was not hugely high (burned out) or very low (a direct connection that should not exist inside the motor) so I hadn’t fragged the bigger hardware. Just one chip.

With the help of someone hiding from work at makespace, I worked out the problems I had left – chiefly that the power supply to the working motor chip was not seated properly, or was somehow resisting. I suspect a bit of fluff or dirt in the breadboard, but whatever it was, the gantry started doing what it should have when I pulled out the jumper and put in a different one to different holes.

Having someone who knows what to look up and why makes a huge difference. I’ve mostly done this project on my own, but today someone else’s knowledge took a couple of hours of what would have been hopeful poking and prodding, and made it efficient. (I need to grab the oscilloscope as a reflex, not after trying lots of other things.) So, I had the Z axis motor working, and the X axis motor moving from the same Arduino, and I haven’t yet built the Y axis at all. I’ve got about 3 weeks to do that.