The idea of this project is to be able to record all acceleration of the rocket throughout the the entire launch. The tracker will also have a GPS receiver that can log it's maximum altitude as well as track its decent to aid in finding it's landing location in the event of a launch where the rocket landing ends up not being visible. This GPS data will be transmitted through a long range Xbee tranceiver.
The basis of the performance data is an Analog Devices ADXL accelerometer. These accelerometers are very cheap and very accurate. They are available in different models with varying degrees of g resolution. The model I am using here is the ADXL330, a three axis +- 3g accelerometer.
The +-3g of resolution is fine for testing, for the actual rocket launch I will be using a +-18g accelerometer to capture launch and decent data.
The ADXL is a pretty small SMD device, so soldering was a little tricky:
The prototype I am making here is a testing base that will be used for debugging and developing the base station receiving software. I envision making a simple and cool app that will control and display all functions of the rocket from launch to landing. The design is based around a PIC18 series microcontroller. Initial performance testing and range testing will be performed by mounting this prototype to a remote controlled truck to gather data.
The tracker under development on my bench:
The finished prototype:
Please note that this device is much too big and heavy for use in a rocket. The final version will be made mostly of SMD devices on a PCB I design using Eagle. Lithium Polymer batteries will be used to save weight as well as using a smaller GPS receiver. I need to be able to save every gram of weight possible.
The device is currently working flawlessly as I have tossed the device around outside my home and been able to capture the data from it. Truck testing will occur this coming week or two, I will be able to display actual data at this time.