APRS Tracking System Flies Your Balloons

Looking for a way to track your high-altitude balloons but don’t want to mess with sending data over a cellular network? [Zack Clobes] and the others at Project Traveler may have just the thing for you: a position-reporting board that uses the Automatic Packet Reporting System (APRS) network to report location data and easily fits on an Arduino in the form of a shield.

The project is based on an Atmel 328P and all it needs to report position data is a small antenna and a battery. For those unfamiliar with APRS, it uses amateur radio frequencies to send data packets instead of something like the GSM network. APRS is very robust, and devices that use it can send GPS information as well as text messages, emails, weather reports, radio telemetry data, and radio direction finding information in case GPS is not available.

If this location reporting ability isn’t enough for you, the project can function as a shield as well, which means that more data lines are available for other things like monitoring sensors and driving servos. All in a small, lightweight package that doesn’t rely on a cell network. All of the schematics and other information are available on the project site if you want to give this a shot, but if you DO need the cell network, this may be more your style. Be sure to check out the video after the break, too!

27 thoughts on “APRS Tracking System Flies Your Balloons

    1. No, I have not attempted to include nor reproduce the SmartBeaconing in the current 2.x firmware. I considered it early on as this controller may have other applications outside of HAB, but ultimately decided to keep it simple(r).

      It does have four different modes of operation that are configurable through the ArduinoTrack Configurator including: 1) a simple time delay of X seconds, 2) an Altitude-based delay were it delays X, Y, or Z seconds depending on the altitude, 3) a Speed-based delay (similar to #2 except based on speed), and 4) a time-slot parameter where it transmits the packet at X and Y seconds past the minute, according to the GPS clock.

      When I fly, I typically will use Altitude-based beaconing and turn the packet rate up fairly high (20-30 second delays) for altitudes less than about 3,000m MSL. Above about 25,000m MSL I will usually turn the rate down to about 30-45 seconds to get more resolution at the time of burst (and also to help compensate from the antenna shadow that two vertically oriented antennas get when sitting on top of each other). The balance of the flight usually runs about 45-60 second delays.

          1. You could use licence exempt frequencies if allowed and follow the local rules and regulations for licence exempt transmissions. You also need to do lots more before you send up a balloon such as checking with and notifying air traffic control. In the UK HAMs are forced to use licence exempt due to the local regulations so there is lots of equipment available for balloons on licence exempt frequencies.


    1. Ironically, in the UK you may NOT use amateur radio for this as airborne operation (/AM) is unconditionally forbidden. However it is apparently legal to use licence free low power transmitters, one frequency being inside the 70cm amateur band, and many do.


    1. I think this phrohibition is only for 800MHz cellular phones:

      Commission rules governing the use of airborne mobile devices vary significantly among
      services. Specifically, airborne use of the 800 MHz cellular band is prohibited and airborne use of the
      800 MHz SMR band is prohibited on aircraft that typically fly at altitudes over one mile.12 There are no
      such restrictions on airborne use of the AWS, PCS, WCS, 700 MHz, or AWS-4 bands.13 As noted above
      resolving these inconsistencies is one of the primary goals of this proceeding.

      1. Even if that is the case, they probably will not work at high altitudes as they will get too much interference from many distant masts all on the same frequency, so they may only work close to the ground, and if the balloon is falling quickly they may not connect and get a message through before landing a few inches from the soil. At that time then they may not get a signal as they are so close to the ground in probably a rural setting. You cannot rely on a cell signal for balloon recovery or tracking. Follow the advice of those who have recovered balloons before.

  1. Even if you’re not licensed as ham radio operator, you may not need the ham frequencies to work this. All you need is a transmitter to send the packets and another to receive. Not sure about how legal it is, but FRS radios are plentiful enough to experiment with as well.

    1. On FRS, there are very restrictive rules about sending data. The data transmission can’t be automatically initiated, it must require a button press by the operator of the radio, or be transmitted as a response to an interrogation from another radio. Plus, if you use some non-standard means of sending the data, then you will have to build and maintain the network of ground stations to receive the data.

      I’d suggest just getting a ham radio license. It’s cheap (about $15 for 10 years, with free renewals thereafter — cheaper and longer-lasting than a cheap bubble-pack FRS radio). It’s simple, with a short 35 question multiple choice test. Study guides are widely available. My friend’s eight-year-old son did it; you can do it too. It’s cheaper and easier to get the license than it is to deal with issues around the infrastructure required to receive the transmissions. Plus, it opens a whole world beyond just APRS.

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  3. How about utilizing the 23cm ham band (1200mhz) for the uplink frequency to APRS satellites and ballon digipeaters? The satellites / ballon downlink frequency could remain on 145.825MHz. This would allow for really compact and portable directional or hemispherical antennas for transmitting up to APRS satellites.



    Jim – KH2SR

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