profmason.com

November 28, 2006

PicAXE data logger

Filed under: Daily — profmason @ 8:57 pm

Smoz-screenshot-20.jpgtarting work on a data logger based on Peter Anderson’s design. First interfaced two switches to inputs 0 and 1 and made them drive a pair of leds to show the state. These switches will handle telling the data logger to

  • (0,0) Nothing
  • (0,1) Clear memory and reset
  • (1,1) Take Data
  • (1,0) write data to serial port

Once that was working I interfaced a 10K pot to act as a voltage divider into Pin 2. Any form of analog input that is conditioned to 0-5 Volts could be input here. (Note keep currents reasonable but that shouldn’t be a problem for most analog inputs!)
Following Peter’s code I read from the ADC and store it into the EEPROM on the Pic. I made several changes to his code.

  • You don’t need to reset the PIC to do a new command. Once it is initialized it waits for a command. Press button 1 to read out. Press button 2 to clear memory or Press both buttons to start data logging.
  • dataloggerboard.jpgDuring the data logging you may press and hold button 1 to stop logging and readout. You can then either press button 2 reset, or press both buttons to restart the datalogging from the previous point.
  • Two LEDs now signal commands if you are not connected. LED 1 signals readout, LED 2 signals reset, Both LEDS flashing signals initialization. LED 2 flashing signals data collection.
  • Program produces comma delimited output which is more friendly to graphing programs.

My code is available here: datalogger.txt

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