Wednesday, September 30, 2009


With school starting back up, I now have time once again to work with APRIL. I have begun a research internship (for college credit, likely 3) with UROP under Professor Olson and will continue where my summer fellowship left off. As of now I am continuing to work on the half-duplex serial communications (for use with the ax-12+ servo). Although in theory everything should be working great, I have run into one serious issue. Transmission to the servo is working fine, it accepts commands, but unfortunately the receiving of signals from the servo is failing. The issue is intermittent, which in my experience is due to either a mechanical problem or a hell of hard to find issue in the electronics. In this case, I think it may be a noise issue. I set the non-active pin (either Rx or Tx) to be high impedance and while that reduced the failure rate, there is still a considerable failure rate in receiving bytes. As of now it is only successful in retrieving 2/5ths of the data sent to it. The bytes received randomly varies between being off by 0-2 byte offsets. I'm almost confident it's a noise issue. The oscilloscope has given me some clues and I'll look into it more probably Friday.

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