Our PongSat ball fully assembled.Today, our first PongSat experiment will be launched to the edge of space! JP Aerospace, a group located in California, offers to fly student experiments that fit inside of a ping pong ball to the edge of space, often over 100,000 feet above the surface of the Earth. Did I mention that they do this at no cost to the experimenter? To get started, you only need to send an e-mail to jpowell@jpaerospace.com.

With the help of my two boys, we created a ping pong ball experiment to measure the temperature and humidity over the course of the ascent and descent of the balloon used to carry the balls up to space.

Our PongSat was built in March of 2011. It contains an Arduino Pro Mini running an ATmega368 microprocessor at 8 MHz (0.5% tolerance). It is a 3.3 volt low voltage board weighing less than 2 grams. The total cost of this board (from Sparkfun) was $18.95.

The inside of our PongSat ball, ready to be assembled.The board is powered by a single 1/2 AA Lithium Thionyl Chloride 3.6 volt 1.2 Ah battery. Lithium Thionyl Chloride batteries have a unique property in that they will function in very cold conditions, down to -55 degrees Celsius. The battery cost us only three dollars.

Connected to the Arduino board is a Sensirion SHT15 digital CMOS humidity and temperature sensor. 512 temperature and 512 humidity values will be stored to the Arduino’s EEPROM memory over a course of three hours. The boys selected readings to be taken about every 21 seconds, so we should fill the available memory locations during the flight.

We wrapped as much of the ball in metal tape to try to deflect as many cosmic rays as possible. We weren’t sure what would happen if we didn’t protect it, but after looking at images of other satellites, we determined they covered the devices in a gold colored film. We used what we had on hand, which happened to be metal tape.

The source code for the Arduino board can be viewed (and used) here. Feel free to use this for future experiments, and hopefully improve on what we have done.

To view the PongSat experiment results, please see the results page.



2 Responses

  1. Hi,

    I’m working with a group of sixth graders, and wanted to see if I could put together an experiment like this as well.

    I obtained the components that you talked about, but I have minimal experience with wiring the boards (being more of a programming than EE sort of fellow). I was wondering if you still had a wiring guide or diagram for this experiment.


    • Everything I kept regarding this experiment has been posted to the site. The good news is that using a temperature and/or humidity sensor with an Arduino is an often-discussed project on the internet, so finding another site which walks you through it shouldn’t be too hard. Ladyada has a bunch of good tutorials. I’d start with this one. The code for our PongSat can be found here. Good luck with your project!

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