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Motion sensitive, LED flicker circuit? Answered

Hey clever people!

I am working on a project with a friend which is basically a backlit sign, it will be lit with a 4-5 meter LED strip which runs on 12v. But will be mains powered. (just the LEDs are 12v)

I am looking to achieve an effect whereby the sign has a passer by and is disrupted, flickers (randomly) for just a few seconds but then returns to a solid light when there is no or less movement/change in light. 

I am open to all kinds of suggestions and have some flexibility within the project to allow for extra components.

At the moment I do not have any components, I may however have access to a raspberry pi or something similar!

I hope someone can help!

If successful I will be sure to incooperate this and the help in to my very own instructable for the initial project.

Thanks in advance!



3 years ago

You have a 2 part problem.

1. Sense the person. Most PIR motion detectors have a switched output (relay)

This could be used to signal to your raspberry pi or other micro (arduino, Picaxe etc) just like a switch.

2. To get an LED to flicker like a candle the easiest was is to play music to it via a digital output. Personally I like to play Happy Birthday.

the rest is simple programming.


3 years ago

The easiest person detector is a light-on (reflect) or a dark-on (shadow) sensor, white light or infra-red light or microwave or ground tremors.

More complex is mini wind caused by a body in motion detector (pic # 3) a piezo flag that generates enough of a voltage to trigger a 555 IC.

If you like sophisticated, play the "EVERYTHING THAT MOVES uP DETECTOR"

Let me know here IF any of this is interesting to you ?

Then we can talk how to put some of these together.


3 years ago

How do you want the flicker - abrupt off/on, fading, sort of moving along the led strips or something different?

Is it perhaps meant to be like the ever flickering neon in just about any gumshoe flick (think Philip Marlowe et. al.)?

What's your experience level in welding up circuits and such?

A Pi wouldn't be my first choice for something as simple. For simple I/O, I'd go with a bare naked micro-controller, or, if that sounds scary, you might wanna spend a small cheap Arduino clone on the project.

If you're going for "faulty neon effect", it might be best to only flicker some of them and leave the rest constant - but you have to be the judge of all this and that - It's your idea after all :)

You're welcome to PM me, if you think that I can be of any help.


3 years ago

If you can understand schematics, these give you an idea about blinking arrangements of in your case LED strips in place of LEDs.

Next we look as sensors