May 28th, 2013
I wanted to put a bunch of LEDs in the ceiling of the 73 VW bus I have. I finally put the arduino to use in this project. The arduino controls some (4) TLC5940 LED drivers, and an Android through an app I wrote communicates with the arduino via serial bluetooth adapter. There are 64 LEDs and each is addressable individually, and can be faded on or off. It's pretty basic but it was the most elegant way I could think of lighting up the inside of the bus. The end result was something I'm pretty happy with...it works well and looks pretty cool.
I also wrote some stuff to measure the cylinder head temperature on the engine via the stock fuel injection temperature sensor. The temperature sensor is just a resistor that changes its resitance as the engine heats up. I found the following graph on Ratwell's site and then fit it to get a function to convert the resistance to a temperature. The temperature displays on the phone app. In the future I'm going to be measuring the main and aux battery voltages, as well as the RPM via hall sensor.
In the future I might ditch the arduino for something faster like a raspberry pi, as there are some pretty annoying performance issues with generating tons of serial interrupts. However, the arduino is neat because it's very low power.
The stuff used: