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Project:SpeedAdjustableBikeLight: Difference between revisions
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New link [http://www.mikrocontroller.net/attachment/14850/BikeLight.pdf on impedance matching and MCU control] of bike lights :). I am not sure what this means for my circuit and plans. | New link [http://www.mikrocontroller.net/attachment/14850/BikeLight.pdf on impedance matching and MCU control] of bike lights :). I am not sure what this means for my circuit and plans. | ||
Since the mosfets and vregs are surface mount, it made sense that the MCU be a surface | |||
mount part as well. I choose the ATTINY84, as cheap, and with 14 pins it has enough I/O | |||
to drive 4 mosfets, sense the speed, the available voltage, the lighting conditions and still have the old style JTAG debugging interface. | |||
A rough thought that SPI or TWI might be enough to to talk to other devices later (USB, ZigBEE, GPS).. and the pins for these are all on the JTAH header :). | |||
Ongoing... | |||
* How to do solder stencil? On laser cutter.. | |||
* How to do solder prep? Sqeegee.. | |||
* Soldering? Frying pan.. | |||
* Validate the schematic and board? | |||
* Have the boards made.. | |||
Thoughts on the heat sink: | |||
Plan to make a simple heat pipe. Start with a copper tube long enough to mount across the handle bars. Flatten spots in the tube to mate with the LED aluminium carrier boards at angles that get the LED light pointed on the road, not in drivers eyes. | |||
Add water and heat it up so it boils, and seal it while filled with steam. The steam will condense to form a partial vacumn. Sounds simple! | |||
Start software development. | |||
==Indicator LED== | ==Indicator LED== | ||
