Sounds like a plan.

Depart: Pegasus Ice Runway, Antarctica ~ February 25, 2006
Arrive: Boulder, Colorado - May 27, 2006

Saturday, April 15, 2006

So you thought this was just a travelog?

Spent a fair amount of this morning ironing out a few weird little problems with my stepper driver thingy, and came up with a couple potentially handy tips:

* If you leave a jameco (likely others as well?) prototype board sitting around for a while without using it, some kind of insulative crud just might appear on the contacts, giving you some really fun bugs to track down. Highly recommend at least dusting them out before use...

* Filter caps on the power rails for L297 s are absolutely essential - surprisingly even if you're playing with the control side of things and don't even have the power side hooked up! Had a weird issue where sometimes the chip would start up in "wave drive mode," which is essentially what you get if you imagine taking a half step switching pattern and remove the full steps from it. The motor will still step just like in regular full step mode, but with less power since there's only one coil energized at a time instead of the pair used when in full step mode. Adding a .0047uf cap between the power rails right next to the chip appears to have fixed the problem. Also going to play with an RC network on the reset pin to make a soft start sort of thing since this board is going to end up used in an electrically noisy environment (EDM machine?)


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