DSP + Arduino

Amanda Ghassaei, who has this amazing project I just found out about, also has a great Instructable for doing DSP with Arduino. A few hours and one blown op-amp later, I was able to get my Arduino to pickup my bass playing. It samples around 38.5 kHz, but I only had it send serial data back every 10 ms (a measly 100 Hz). Still, I was able to generate this graph with the data. You can see the clipping where I cranked it up to test the peak indicator LED.

The atmega328 has 32Kb flash memory. If I used half of that for a delay line, 16,000 samples / 38500 samples/sec = .42 second delay. I could get a longer delay by using external flash (e.g. SD card), but I worry that the read/write time would be low. It will be interesting to apply some of the concepts from class to actual signals. What does a 50-point averager do to my tone? (answer: probably reverb)

There's not a lot I can do with this now, since I can't hear the results of any processing yet. I just ordered a DAC0808 8-bit digital-analog converter. (The new DUE has two built-in DAC outputs, as well as PWM, although it still isn't an ideal platform for DSP). Eventually, I would like to get an FFT algorithm running and make a tuner. That will probably have to wait until after finals, though.

EDIT: Just found out about wki.pe/Resistor_ladder s.