I started back up on my microcontroller development and decided it was time to get my 1-wire iButton datalogger programmer off of the breadboard and into a portable device!
The goal is a device to start / stop and view status of iButton temperature and humidity dataloggers in the field without having to use a laptop.
I have switched from a Sanguino to Arduino Pro Mini, which will allow everything to fit into SparkFun's small project enclosure.
The serial (I2C) Newhaven LCD I was using pulled a lot more power then the data sheet had indicated. The peak load was 236 mA, which is way beyond what a 9V lithium battery could handle for any reasonable period of time.
Fortunately, Newhaven has a side lit LED 20 mA backlight Serial LCD that is a drop in replacement: NHD-0216K3Z-FS(RGB)-FBW. The total current with the Arduino dropped from 236 mA down to 41.5 mA. Using PWM on the Arduino to drive the backlight at reduced brightness with no flicker, the total current dropped down to 25.4 mA! I recommend this display if you plan to use a serial interface and need low power. This display needs two additional wires for supply and ground for the backlight, but it was worth it!
Test renders with the enclosure and updates are at http://arduinofun.blogspot.com/