Build Project: Device to play mp3 file when hand placed on car bonnet

Hello

I'm looking to have an electronic device made which will play an mp3 file when a circuit is made.

The device is to go on a promotional vehicle which will have a hand print on the bonnet.

When a person puts their hand on the bonnet, it will play and mp3 file (30 seconds long) and then stop until the next person places their hand on the bonnet.

I'd imagine that this device would have to sit under the bonnet and should be somewhat weather proof and would attach to a small outdoor speaker.

I'd be interested in hearing from anyone who could build such a device and would be able to provide a competitive quote for the finished product.

Thank you

David

You might want to look into using a picaxe 18m2 chip as it has capacitive touch switching built into it, and could handle all the required controlling you need in one little chip.

Pete.

What's a bonnet? Don't think you mean some sort of fancy woman's hat...

What's a bonnet? Don't think you mean some sort of fancy woman's hat...

Click to expand...

We could say HOOD but then that could refer to a uncontrollable youth

It will be very hard to capacitively sense a hand through a very large 1mm thick steel sheet.

If it's allowed I would drill a small hole (3mm) in the bonnet and use a reflective infra-red sensor to detect the hand.

It will be very hard to capacitively sense a hand through a very large 1mm thick steel sheet.

Click to expand...

Yes it would, but i was thinking more along the lines of a piece of copper foil stuck to the underside of a sticker hand print, as the capacitor sensors require a plactic or non conductive layer over the metal to work properly.

The easier way would be to put the hand print onto a glass window and stick the copper foil (or could be any metal you can solder a wire to, even a scrap of PCB) on the inside of the glass as the sensor will work through glass.
In program you can set the sensitivity required, they really are a very easy system to use.

Pete.

That's a good idea, putting the foil on top of the bonnet. It didn't occur to me.

A minor problem would be you then have to run a shielded high frequency wire from the handprint on the top of the bonnet to the waterproof control box. That still might work ok if the handprint was near the bonnet edge.

That windscreen is looking like the best option...