Bitcoin-Mate conversion rate display

Building the Arduino image

$ wget https://github.com/dnet/arscons/raw/master/SConstruct
$ scons build

Uploading the Arduino image

Default config

$ scons upload

Example for ATmega168-based boards

$ ARDUINO_BOARD=atmega168 scons upload

Connections between the Arduino and the LPT port

• LPT data bit 0 (DB-25 pin 2) to Arduino analog pin 0
• LPT data bit 1 (DB-25 pin 3) to Arduino analog pin 1
• LPT data bit 2 (DB-25 pin 4) to Arduino analog pin 2
• LPT ground (DB-25 pin 20) to Arduino ground (any one of them)

Dependencies for arscons build process

• Arduino 1.0+ (if you have an older version, rename *.{ino -> pde})
• Scons (Debian/Ubuntu package: scons)

Building prelay

Compilation is pretty straightforward using GCC, but you have to set the set-UID (SUID) bit in order to use the tool without root privileges (and you don't want any network communication with root, right?)

# gcc prelay.c -Wall -o prelay
# chmod +s prelay

Running it regularly

Just put the contents of example.crontab into your crontab to query and display the current value of 2 EUR in mBTC on the display.

Since bitcoinchars.com is a free service, don't query it too often, as they may ban you from using it by your IP address.

License

The whole project is available under MIT license, see LICENSE.txt.