How does one test that an HM55B compass chip is working
aladas
Posts: 18
I have bought and installed a Parallax HM55B compass chip and run the TestHm55bCompass.BS2 test program. After some wiring errors which made me add some debug lines to show whether I was getting a status I found the values shown were only in a small band of values. On the forum I found a suggestion that being too close to the servo motors would be producing too much magnetic field for a good reading, so I moved the chip off my BoEBot board and onto a bread-board with a 10-inch length of ribbon cable. Now I am getting readings, but even if I spin the board through 360 degrees the reading on my debug screen does not move more than one or two degrees off 90 degrees, and even that variation seems random. I checked that my circuit was as it should be and the only oddity was a resistance of perhaps 5 ohms between the Vdd pin on the breadboard of the BoEBot and the one on the X1 header, though each gives about 4.8 volts over Dss when the board is powered up. Vnn gives 5.1
The board and the Stamp, my wiring and my code seem to be in good working order; now my next suspect is that the compass chip is defective. Can any of you gurus suggest a still purer way of verifying if the chip is good or not? Assistance much appreciated as I would have transport difficulties returning the chip to Parallax.
-A
The board and the Stamp, my wiring and my code seem to be in good working order; now my next suspect is that the compass chip is defective. Can any of you gurus suggest a still purer way of verifying if the chip is good or not? Assistance much appreciated as I would have transport difficulties returning the chip to Parallax.
-A
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This issue has been handled via e-mail. Take care.
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Chris Savage
Parallax Tech Support