Pumpkin

A carved pumpkin with a high-powered LED that I made for Halloween 2011.

Video of pumpkin in action

Building

• Soldering instructions and general circuit design from Power LED's - simplest light with constant-current circuit
• Specific circuit from High Power LED Driver Circuits

I built out the project in this order:

1. Build constant-current circuit on a breadboard to power one LED channel
2. Adapted the circuit to use the Arduino
3. Wrote a bit of code to test out PWM
4. Soldered the three drivers
5. Hooked everything up to the Arduino & tested (put the three drivers in parallel)
6. Coded up the light show

Diagram

(Credit: Dan Goldwater, High Power LED Driver Circuits)

Parts

• 1x Arduino Duemilanove
• 3x 1W 100kΩ resistors (R1)
• 3x 1W 1.5Ω resistors (R3)
• 1x High-power 3W RGB LED (LED) (350mA forward current per channel)
• 3x BC 547 (Q1)
• 3x IRFZ44N (Q2)
• 1x 5V, 2A power adapter

Guts