Case 94: Bill Bowden: Night Rider

November 20, 2006

To see and be seen after dark on his bicycle, Bill designed this 40-LED light. He configured a 555 timer IC to generate a continuous on/off timing cycle to alternately flash two groups of 20 LEDs. The device operates on four AA batteries, keeping things bright for even the longest night rides. You can extend battery life with a second circuit Bill designed that uses a short duty cycle to flash a single group of 30 LEDs .

Download Bill's instructions . Scroll down to see the parts list.
40-LED Bicycle Light
Amt Part Description Allied Part #
1 LM555CN Timer 263-0133
1 4.7iF capacitor 852-7070
3 2N4401 NPN Transistor 431-0408
40 Red LED 670-1224
2 220 ohm resistor 296-6306
20 120 ohm resistor (200 ct) 832-0212
2 2.2K resistor 296-6318
1 47K resistor 296-2181
4 Alkaline Battery (AA) 737-0520
Additional parts required
Perf board
Click here to download Bill's instructions

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