TechCrate 004 — Spooky Eyes Jack O’Lantern

Build two blinking LED eyes that switch on in darkness. A 555 timer controls the flashes while a phototransistor responds to light.

• 1 × 555 timer chip
• 1 × phototransistor
• 2 × red LEDs
• 2 × 470 ohm resistors
• 1 × 10K resistor
• 2 × 100K resistors
• 1 × 10µF electrolytic capacitor

Breadboard, 9V battery, Battery snap connector, Jumper wires.

Subscriber instructions PDF · Build video and customer files

Optional: compare resistor values with power disconnected before exploring the light-sensitive circuit. The complete build and its checks work without a meter.

ProTechTrader Large Screen Digital Multimeter PDM-711