Arduino offers quite a few digital outputs, but sometimes you want even more… When a keypad and LCD are connected, it doesn’t remain much free outputs.
Today I found out a simple solution for that – EZ Expander shield. The shield utilises two shift registers, 74HC595 to ‘multiply’ digital outputs. Of course, the additional outputs can be used only in output mode (there is no possibility to read from them).
So, this is the shield, but if you need more outputs (LED diodes?), then you can use only EZ Expander’s library and any shift registers (74HC595 of course will fit). Just wire up the registers and send values to them with simple digitalWrite – take a look at ‘Advanced API usage’ section in the documentation. But don’t fear the ‘advanced’ :)
There is a few other interesting things at nootropic, for example Arduino-based video game system. It uses TVout – library for generating composite video on AVR chip (so, Arduino too). If you want to know, how to generate video with Arduino, check the Sprae’s blog (Arduino as a graphics card – unfortunately, only in Polish).