Our second flight was on May 15th, 2010. This was after the delivery of many little red boxes from Sparkfun Electronics.
For this flight the goal was simple, take some pictures and don’t lose the payload again. This payload string consisted of 3 separate packages, 2 radios and one camera payload. In the future I plan on adding details on the payloads but for now here are the basics.
The first radio package was the data radio. It was used to send telemetry data to the ground every 2 seconds. That way if the balloon was lost we would have some data to study. The graphs from that radio are attached below. The radio used was a Digi XTend 900MHz 1W radio. This is a license free radio that has a serial interface. The rest of this system consisted of an st711 processor, Venus GPS receiver, 6 degrees of freedom IMU (3 axis accelerometers and 3 gyroscopes), and multiple temperature sensors. It also has provisions for a Zigbee radio to talk with other payloads and on board data logging. These will be implemented in the future.
The second radio actually transmit’s the GPS location by voice. It consists of an FRS (Family Radio Service) radio with a Sparkfun MP3 trigger and simple processor to string together individual words and digits to announce long, lat, and altitude every 2 minutes. This turned out to be a lot of fun because everyone in the chase team could follow the location on a radio.
The final package was the camera package. To make things interesting here we wanted to try some active stabilization. The idea is to add fins to the package that are controlled by servos. These fins would be adjusted to use the vertical flow of air to stop the package from spinning. For this flight we used to cheap key fob video cameras. They have become very popular to add to RC planes. You can see a picture of one of these under S3R-3.
Now for a few of the flight details. We launched at 10:45AM, 45 minutes behind schedule. Remember that everything takes longer than you expect. About one hour and 15 minutes later at 12:03 PM the balloon burst at 82,500 feet. By 1:15 the payloads were safely back on the ground.
The radios both worked perfectly, we had continuous information from both of them. We knew exactly where the balloon was at all times. The problem was we didn’t know where we were. We all had smart phones that didn’t work without a signal. The in car nav. systems didn’t have any of the roads in the area and they didn’t report our long and lat. We finally resorted to plotting our location and the balloons on paper maps. In the end we were able to drive within ½ a mile of the landing spot and walk the rest of the distance.
The last thing to do was look at the videos that we captured. We all rushed to the nearest place we could get lunch and look at the videos (Dairy Queen at Picacho Peak). This is where Murphy took over. Both cameras had been accidentally shut off when they were slid into their spots in the payload.
Being engineers we like charts and graphs. Here are some from the flight.
And here is the KMZ file of the flight. This one includes the altitude info as well.
And of course a few pictures from the launch and recovery.
Gathered around the box with the cameras in it.