How can I get a multi-digit display from RSR Electronics to work with an Arduino?
It appears to be a normal seven segment display:
http://blog.2of1.org/2010/08/27/arduino-library-for-7-segment-displays/
Or check out the playground for more examples.
Onions.
how many are you trying to use? and what Arduino platform are you using as well?
You may need 'more pins'.. so using a shift register chip might be an option for you as well.
Up to 4 digits I would multiplex them, using one transistor per digit to drive the common anode or common cathode, and driving the segments directly from Arduino pins through common series resistors. This uses 7 pins for the segments (or 8 if you are using the decimal point), plus 1 pin per digit (you can reduce this if necessary by using an external demultiplexer chip, e.g. 2 pins for 4 digits). For more digits than that, or if I need to use fewer pins, I would use shift registers or specialist 7-segment display driver chips.
The digit pins can be used to multiplex other devices at the same time, for example I use them to multiplex rotary encoders and push buttons to reduce the number of input pins I need.
I've updated this library for Arduino 1.0 and added support for Hex (actually any arbitrary base up to 16). David Kaplan's site has been down so I am hosting this on my site so it does not vanish altogether.
http://www.earnestdesigns.com/2012/01/updated-seg7-led-library-for-arduino/