Blushing girl doll
Red lights for doll cheeks which are made of white foam rubber. Lights can be switched to fade in or out.
Arduino Duemilanove with Atmega168 microcontroller onboard is used as controlling device. External switch is used as controller.
MCU controls brightness of two LED lights inside doll head.
Power supply is battery of 6 NiMH cells, LED lights are faded by PWM via TIP122 transistor key
Transistor is mounted on heat sink.
Main unit is mounted on PVC plate, allowing actor to wear it on the belt. External switch can be held in hand.
Algorithm and Arduino sketch
Dyty cycle polls S2 switch state. If it if pulled low, MCU receives high level from internal pull-up resistor.
Pulling S2 input low enables fade in, in other case fade out is enabled.
Brightness to PWM level translation happens in logarithmic law, placed in array. This array was taken from
Arduino - Physical Computing für Bustler, Designer & Geeks
Odendahl, Julian Finn, Alex Wengler).
Fade in time is set to 40 ms/step and fade out time set to 100 ms/step, so whole
animation takes 2.56 and 6.4 sec respectively.