Attended: Mengyuan, Creighton, Scott

• Updates:
• To Do:

• Updates:
  • Right before the CDR, made the realization that instead of going through the trouble of offsetting the received signal and using a threshold detector, we could keep the received signal centered at 0V and use a zero-crossing detector. This will simplify our design by quite a bit (we would forego the Schmitt trigger, threshold detectors, and possibly the amplifier). Also, the zero-crossing detector is relatively simple to build.
  • Experiments from 4/12/17:
    • Tested zero-crossing detector with oscilloscope:
      • Initially tried to do it with an op-amp but we were limited by the slew rate. When we did find an op-amp with a high enough slew rate, the rise time was relatively slow.
      • We then decided to test it with our voltage comparator set at 0V, and it gave us much better results.
    • Delay 12.5us using nops:
      • Not very reliable, a better approach would be to try and modify the timer's prescaler and initial value to achieve a 12.5us trigger.
    • Receiver response when sending just 1 pulse:
      • Sending just a single pulse through the emitter still causes a relatively long received signal. Also, there is an audible frequency (~3kHz) coming from the emitter.
    • DigitalWrite() vs. fastDigitalWrite():
      • This is probably the time between the function call and the pin change, rather than the actual rise time, which is a physical property.
      • digitalWrite() rise ~ 22ns
      • digitalWriteFast() rise ~22ns
• TO Do: