1 Sep 2004 ericzayers   » (Journeyer)

The Billy Bass hack is coming along nicely.

  • I modified my PIC programmer with a 10 pin header in order to do In Circuit Serial Programming (ICSP). I like this much better than a boot loader, but I have to figure out if I can isolate the programming pins from the rest of the circuit. I've been programming the chip directly on my breadboard.
  • I've isolated the motor control parts of the circuit and broken them out to my breadboard.
  • I turned a 10 way switch into a voltage divider that I can read on one pin with the PIC's A/D converter. Right now, all the '819 is programmed to do is read the switch and turn some LEDs on to display the output of the switch.
  • I wired up the ISP Chipcorder chip on my breadboard and built the reference application circuit from the datasheet using all the parts I have.
  • The op amp chip that Marty Vona used is now a hard to find part. I hooked it up to a very common LM386 audio amp to the speaker output of the Chipcorder. The sound quality coming out of that thing is really poor. I'll have to figure out how to jazz it up a bit. I'm not really sure what I'm doing with this audio amplifier stuff. I think I will have it drive a PNP and NPN transistor to make a push-pull type of circuit to drive the speaker that I got from the 'techlib' web site.

I really ought to spend some time now to draw up the circuit in Eagle, but I love to solder, so it is hard to resist the temptation to lay down some circuitry.

I found some new stepper motors for the Linefollower robot on eBay that advertized "high torque". What have I got to lose? If these motors are high enough torque, then I might not have to build a gear train after all! However, these steppers are bipolar, so I won't be able to use the darlington array I have now and change to use an H-Bridge. That will mean an extra chip on board to control both motors.

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