README
May 28, 2012
[email protected]
William W. Ward
Copyright 2012 (Licensed as GPL)

What it is:
A simple Arduino sketch and a simple bash script. The script
progressMeter.sh takes the serial port path (under Unix) and an integer
value 0-99 and transmits that as a byte to the serial port.  The Arduino
sketch reads the byte from the serial port and maps it as a value, 0-254
using the Pulse Width Modulation feature of the Atmega to control an
attached voltmeter.  The nominal output in a simple Arduino setup with a
meter will be within the range 0-5 volts.  Some meters may require a
negative voltage to pull the needle down to zero if their springs are
such that they don't automatically home to 0 volts (apparently my old
meter won't return to 0 unless it's pulled down.)

You can attach anything you like, realistically, but you'll have to deal
with calibrating the PWM output to fit the input range of the indicator.
If it's an LED, it will have a narrow range where it emits light
starting at some minimum voltage up to its rated maximum, which is
usually less than 5v.

This is a trivial implementation and clearly the code is extremely
brittle.  However, I wanted to get the proof of concept running for my
own amusement.

- wwward