SparkFun Forums

[itoo73]

Hello everybody,
i need some advice for my project. I want to create a circuit that will have this characteristics:
1) when it detects some movement it will start to fade in - out a led.
2) the range of the detection could be veeery small. e.g. i just want to activate the led on off sequence when the user move his hand in front of a sensor.
3) it has to be portable so i need some type of battery
4) is has to be small.

I did some research and was thinking to use an avr like teensy or the arduino nano or mini and connect a led and an pir sensor like this one http://tinyurl.com/252cxko .
Am i looking in the right direction? Is it possible to attach such type of sensor to these boards?
What type of battery should i search for and how much time is the whole system supposed to be powered by it?
Can this system be done without using an avr by just only using plain elements eg. capasitors transistors resistors etc??
Thanks in advance..

[anhingus]

you could do an invert of this idea.

put a photocell in series with a powered led and use the voltage change on a hand pass as an input.

that is, let the led do its own dimming and pick off the signal.

if you want a last-forever battery, try an LM3909 with this project.

[itoo73]

hmm nice idea...
but if i want to do some more complicated things with the leds and the project will expand and grow i think i will need an avr like teensy or arduino, right?
In case that i use one avr could this be done with this type of sensor?
What type of battery should i search for?

[ferrarif40gt]

I have a question.....When sensor detects something or something moves (according to overview and datasheet), the "alarm" pin will go low. But. Does anybody knows what appened after that?, I mean, the "alarm" pin still in LOW? or will go HIGH inmediately (when nobody activated it). How much time the "alarm" pin is in LOW?

Thanks for ideas!