Pressure / Temperature / Altitude Sensor

Originally we were simply going to launch the balloon with an HD camera and potentially include more scientific equipment if we did a future launch. Looking at other groups’ projects some of the electronics used seemed to be potentially more time consuming and expensive than we wanted to for this project. However, after a few of our items came in under budget I reconsidered the idea.

It turns out there is this great piece of equipment called an Arduino which is very flexible for many different projects. Arduino is a microprocessor (basically a tiny computer) that can take inputs (from humans or from sensors) and produce outputs (turn motors, operate lights, etc.). So, I purchased an Arduino Uno, a BMP-085 Pressure/Temperature/Altitude sensor, and an SD card module to record the data readings.

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For me, this might end up being the most challenging part of the project, and it was a very rewarding feeling once the sensor was working. I owe 100% of the credit for the success of the Arduino contraption to the talented Jeremy Blum. Jeremy had a great series of Arduino tutorial videos that covered everything from the absolute basics to everything we needed to know for our project.

Here are Jeremy’s Arduino tutorials. You can also find his tutorial videos on YouTube.


Hours of thinking…

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Hours of messing with code…

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Cold Weather Test

Cold weather test…

Here is a quick plot of the data value obtained by the sensor. Here the only meaningful curve is the temperature cure as the sensor went from room temp, to refrigerator, to freezer, to fireplace. Obviously the pressure and altitude stayed the same in my house.

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Temperature graph (test run)

If you want to use a similar setup to mine, I recommend: 1) Getting the temperature sensor working over SPI, then 2) getting the SD card to work, then 3) try to get the data from the temperature sensor to actually record on the SD card.

Here are the Arduino files I used for each step as a .txt file that you can copy/paste into the Arduino IDE:

  1. Testing the temperature sensor – [.txt] {outputs the surrounding temp/pressure/altitude}
  2. Testing the SD card – [.txt] {simply records “hello” over and over to the SD card}
  3. Final compilation – [.txt] {here is the final file that takes data and records to the SD card}


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