We had a good tethered launch on April 28th this time at 7.30am. This tethered launch was carried out to test the electronics board (this time Raspberry Pi) and new GPS unit of VisionTek and GPS unit of I-wave systems which can transmit GPS location upto 40km from Earth’s Surface.
The Raspberry Pi is a credit-card-sized single board computer developed in the UK by the Raspberry Pi Foundation. We interfaced a Logitech Webcam, a 9 DOF attitude sensor (which included 3 axis gyro, 3-axis magnetometer, 3-axis accelerometer) to the pi. The Webcam was programmed to take JPEG images. The results of 9 DOF were programmed to stored in a text file on the SD card on Pi. The radio transceiver was provided by Dhruva Aerospace to help us locate the balloon using amateur radio. The FTU (Flight Termination Unit) was also used to test the parachute.
Things that worked:
Raspberry Pi along with the webcam.
The GPS units failed to give the correct location even this time
We lost to recover our payload due to poor GSM network in Hoskote.. Our GPS tracker unit failed to receive any signals after half an hour. After two days some villagers called and informed us on the numbers pasted on the box about the box being there. It was found in a bad condition. We lost our parachute, canon camera onboard. The electronics could not record any parameters due to loose wires present. The 1 kg balloon used was not filled upto the maximum extent also.
Lessons Learned :
Modify the box to be unable to open by the people.
No more loose wires in the circuit. Every thing should be on a PCB.
Helium filling procedure needs more attention.