A friend of mine wants to marry like a butterfly! So she asked me to make an interactive butterfly on a hairpin, to put in it her hair. Is this possible, she asked? Of course this is possible! The biggest problem in hardware was finding a small servomotor, to be fitted on a hairpin.
The other problem in software was programming the ATTINY45 with interrupt and ADC converter (analog PIN) and PWM, for the servomotor. But since I have done that for you (reading and combining codes of others on the internet) you can just upload my code, and make variations.
Then start a production of butterflies and become rich! Because which woman wouldn't be married like a butterfly, there must be an enormous market out there!!!
Step 1: Components
a hairpin! (just ask your girlfriend!)
butterfly (you can the ones on the picture at http://www.dealextreme.com/ )
servo motor ( the smaller the better, the smallest I found was at
(There are smaller ones, see the comments!)
ATTINY45 (8 PINS, yes SMD, you can by this at www.farnell.com )
3mm LED (or even smaller, in any electronics shop like www.conrad.com )
LDR ( Light dependent resistor, under a euro www.iteadstudio.com but to be bought everywhere, nothing special)
one resistor of 4.7 kOhm, (small, for combining with the LDR)
some perspex, (for putting the butterfly above the servo motor)
some thread, (to get the movement from the servomotor to the wings)
some wire, for attaching the components
some PCB with copper you can cut with a knife, for mounting the ATTINY45 without EAGLE (although you can do this properly too of course)
batteries (total around 3V), so no extra resistors for the LED's are required
some paint used for models, making the hairpin and components disappear in the lush hair of the bride
Some components I had to buy especially for the butterfly were the glue and the polyester thread. (glue 3 euro, thread 60 cents on a local market)