Monday, April 13, 2009

Remote GPS tracker + Accelerometer

This summer there are a few projects I have planned. One of the first is a model rocket tracking / data-logging system for some launches I am planning on performing this summer. I recently came across a good supplier of F and G series rocket engines for a very reasonable price. Some of these engines have as long as a 7.8 second burn making them very exciting to see take off.

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.


  1. In case you need some inspiration.

  2. We were passing this link around the Digi office today. Us engineers think this is cool.

    Is your data being logged to local storage or is all of the data being transmitted throughout the launch via the XBee?


  3. It's hard to tell the dimensions of your tracker/accelerometer, but if it weighs less than 4oz, it'll easily fly in a rocket powered by a G motor.

    Consider seeing if there is a rocketry club in your area--visit Nat'l Assoc. of Rocketry ( or Tripoli Rocketry Assoc. ( They would be glad to help with a launch site, any FAA waivers (depending on your rocket's size & planned altitude). And those clubs could also help you get bigger rockets and/or motors too!

    And if you're looking for inspiration/information about rockets you can fly, take a good look at Essence's Model Rocket Reviews (

    Lastly, feel free to email me for more help with the rocket side of the project.

    Good luck!

  4. I'm trying to design something very similar to this. Is there any chance I could get some more information on this project?

  5. Hey, I was wondering if you had any advancements in your design here? You said the next one would be surface mount components and lighter weight GPS and Accelerometers.

    Just wanted to know cause I plan on putting something like this on my Level 2 and 3 certification flights, high powered rocket flight.


  6. I am working on a similar project, not necessarily specific to rocketry, but definitely applicable. I call it Arduemetry (Arduino + Telemetry) and I have been documenting my progress on my website at Take a look and see if you think I'm on the right track or if you can benefit from my work.

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