A Project I’m thinkng about

Not to mention other projects plus a job that are going to get going very soon. But I’m always thinking about how to make things better or extending things to other platforms.

This time what I want to build is a high-intensity LED array based bicycle tail-light with an accelerometer and a micro-controller.

Here is theory of operation:

– When the accelerometer detects a negative change in velocity the a full brightness LED array will flash at a 500ms on/500ms off ratio. When the accelerometer detects no forward motion the LED array will go full brightness on.

-Under acceleration the LED array will dim to 50% illumination.

Doing this with the accelerometer and micro-controller allows that no linkage to the actual braking system on a bicycle is necessary. It’s all senses based on motion.

I look at it this way: obviously power is an issue so it will probably be a rechargeable unit you pop off and charge via a USB connector. Probably use with Li-Ion or Li-Po. And when the Air-Ion batteries become commercially available switch over to one of those.

Now dissipation of heat may be touchy – but I can heat sink the sucker to the bicycle frame.

I have everything I need to prototype this – Arduino and MSP430 and PIC chips, high intensity LED’s, just need to pickup an accelerometer and they’re dirt cheap. But to prototype I’ll need to use a breakout board. It’s $11.95 – not bad. And looking at the datasheet for the chip itself – it’s an LGA package which means I’ll eventually have to design a circuit board, have a few produced and test. I’ll want to incorporate everything on the board, controller, power and output connectors, etc.

The reason I don’t like LGA – the pins are all underneath the package. Yes, I could reflow it in my toaster oven. But I’d have to time it and probably modify my toaster oven to get the temperature ramps right.

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