These are a few simple LED circuits. They can be used as warning lights - as fake motorcycle alarms - as a doorbell substitutes for the deaf or hearing impaired.
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Simple LED Circuits

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Flashing Doorbell
For The Deaf
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Fake Alarm - Circuit No.1

Detailed Circuit Description

Flashing LEDs can be used to create the impression that an alarm has been fitted. Or they can be used in conjunction with a real alarm - to warn-off a potential thief. If you replace R1 with a 4M7 pot - you can control the rate at which the LEDs will flash. The slowest rate is about one flash per second. If you'd like a slower rate - increase the value of C1.

TURN ON
Turn On Flash
THE FLASH

I've used this first circuit on several motorcycles. I mounted the LEDs inside the lights. They were pushed through small holes drilled in the plastic reflectors. I put the control circuit behind the reflector in the tail light.

The small number of components means that the circuit can be built without a circuit board. The parts can be soldered directly onto the pins of the IC. Roll the whole thing carefully in a little BluTack - and cover the outside with several layers of electrical tape. You should end up with a small cylinder - that's well insulated and relatively impervious to moisture.

If you're installing this device on your bike or in your car - there's no need for an on/off switch. You can just leave it running all the time. However - you must fit a 1-amp (or even smaller) fuse as close as possible to your power source. This Is Very Important. The fuse is there to protect the wiring - NOT the components of the circuit. If you're mounting the LEDs inside the lights - you'll need to choose a spot that's not going to get too hot.



Fake Alarm - Circuit No.2

Detailed Circuit Description

The last circuit will flash up to two groups of 5 LEDs in tandem. This circuit will flash the two groups alternately. The alternate flashing creates the illusion of movement - and makes the display more eye-catching. Note that - although I've drawn the two groups of LEDs side by side - the individual LEDs can be mounted in any pattern you like.

TURN ON
Turn On Flash
THE FLASH

A Few Examples Of Eight-LED Displays




Warning Signal - Circuit No.3

Detailed Circuit Description

This circuit is like the previous one - except that it will flash up to 15 groups of 5 LEDs per output. The LEDs will also flash at a faster rate - and they will glow at their full brilliance. Unlike the more discrete "alarm fitted" indicators - this circuit is designed to get your attention. Again - although I've drawn two groups of green LEDs side by side - the individual LEDs can be different colours - and they can be mounted in any pattern you like.


TURN ON
Turn On Flash
THE FLASH




TURN ON THE FLASH

Learn More About The Cmos 4001 Learn More About The Cmos 4011

Flashing Doorbell
For The Deaf
The Rest of Ron's Circuits Write To Ron More Free-to-Use Circuits Circuit Exchange International