Bike lights feature

Bike Lights Design

Lights are a necessity if you are going to be on the road at night. This applies to anything that moves–car, bike or pedestrian. I will document how I compared designs and settled on assembling a design based on Revolights for about $40/wheel. I call them SparkleLights.

 

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batteryPhoto

Android Phone Battery Calculations

I recently received a new Samsung Galaxy S3. Coming to Android 4.1.1 from three years of iOS is quite liberating. The phone just gives you so many more customization options and control. Amongst all the new features though, I really like the power usage meter under Settings > Battery. It presents a nice graph that shows battery charge over time and the applications using the most power. I thought it would be fun to interpret the data a bit and calculate the “full charge time” and the charge rate in mA. My calculations are below:

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comparison

Comparing PCB Manufacturer Prices: OSH Park, Circuits.io, iTead Studio and Upverter

For low quantities of PCBs, there are two main services available that I am aware of: OSH Park and iTead Studio. They have their pros and cons, but a new kid has come onto the block: circuits.io. They use OSH Park’s facility, but have a different pricing formula. I have done some analysis to find the best vendor for the project.

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overview2

Arduino-based Point-of-sales system

I made a point-of-sales system using Arduino, a receipt printer, a 20×4 LCD and a keyboard on October 13, 2012. I thought it would be a good exercise for me because I really wanted a reason to use the Adafruit receipt printer and I would have an example of an embedded systems project that was complicated enough to require a state machine. I’ve documented all the hardware and software below.

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