I will be teaching a quick course on using Arduinos at a Hackerspace camp this summer, and want to use some small BLDCs that I've scavenged out of CD-ROM and DVD-ROM drives.
The motors come equipped with Hall sensors, but I have no way of determining which pin leads to what, and I can't get at the sensors to see what model the chips are. On most of the motors I can determine which pins have to be power and which are signal, but that doesn't tell me what the polarity is.
My problem is that I don't want to fry the Hall sensors while trying to guess which is positive and which is negative. Any suggestions, aside from being ready to chuck half of them in the e-cycling bin because I've destroyed the sensors?