Living Architecture Fall 2008 Columbia: piezo buzzer input / output

Tuesday, September 30, 2008

piezo buzzer input / output

we set up a system using piezo buzzers as both input and output. the input uses the piezo crystal's vibration sensor to trigger the output to make a noise. we had some difficulties finding the right code, and in the end, we were able to use another group's "touch sensor" program as a generic place to start.

Here's the code:

' {$STAMP BS2}

' {$PBASIC 2.5}

TriggerPin PIN 0 ' Input Pin

Main:

LOW 15
IF TriggerPin = 0 THEN buzzit ' Check for trigger, if pressed turn on buzzer
DEBUG "off", CR ' show off
PAUSE 1000
GOTO Main ' loop
buzzit:
DEBUG "buzzIT", CR
HIGH 15 ' turn on piezo buzzer at pin 15
PAUSE 4000
GOTO Main ' loop

we were expecting the output buzzer to only trigger when the input was activated, however, this code seems to treat the input as more of an on/off switch.

the output buzzer also displayed some behavior that we're not quite able to explain. moving/touching the output was somehow disrupting the circuit and producing a strange/interesting noise effect.