Hi guys. So I made this universal device for visually impaired. It's clock, stopwatch, egg timer, water level detector and meter. In future, I want to add a color recognizer, sound recorder, calculator, theremin, haptic feedback device and much more. (Rfid tag reader? Thermometer? Compass? (that round one))(But I'll have to upgrade to atmega to achieve such goal.) As for now, all design is build around attiny85 single chip, rotary encoder (multipurpose), two buttons and piezo buzzer. And some recycled parts, such as connectors from old 9v batteries and energit (altoids) can. Overall costs: <5 bucks. Estimated overall costs of sum of (usually single purpose) devices capable of same thing: OVER NINE THOUSAAAAAAAAAAAAAAAAAAAAND!!!! No, seriously, It could get well over 200 bucks. So, yeah. I guess that's it. I might do a tutorial and post codes online if anyone is interested. Based upon previous work: Time.h http://arduino.cc/playground/Code/Time
PinChangeInterruptSimple.h and whole core from http://code.google.com/p/arduino-tiny/
and rafbuff's rotary encoder handling algorhytms. Here's a nice little video:
Sorry about the quality. Dropped my camera on floor, had to use mobile phone.