After our first two launches which were not as successful as we would have liked, we sat down and planned our next move. we wanted to make another attempt as soon as possible, and as our budget deflating, we had to make it cheep. till then, we were buying HABduinos from the UK. which worked fine, but at £83.99 a unit (not including arduino), we had to go the DIY route. what started as a bunch of wires ended up as a very nice APRS tracker dubbed “Balloon3”. we used a Chinese 3.3v Arduino mini as CPU. we had couple of uBlox neo-6m GPS modules and after some research, dropped the Radiometrix HX1 for a cheaper DORJI DRA818V. I’ve also added a relay to activate the NiChrome wire balloon release mechanism.
Version 3.1 added a temperature sensor and a test circuit for NiCh wire. Version 3.2 is an even smaller footprint (5x5cm, 2x2inch) which is cheeper to make.
total budget is $10 for the arduino, $12 for the GPS, $13 for the DORJI & $1.5 to $5 for the PCB. I’ll add $5 for the rest of the components & connectors, and you’re shy of $50.
In the meanwhile i’ve been researching on a high-end platform. I’ve set the following requirements :
- APRS Tracker
- Balloon Release Mechanism (with continuity diagnostics)
- picture downlink transmission
- minimum batteries to save weight
- Inside & Outside Temp Sensor
and some nice to haves:
- Second release mechanism
- replace relays with transistors
- Barometer
- ability to uplink commands to the Mission Computer
let me try and elaborate on each issue and the design considerations it requires:
Continue reading High Altitude Balloon – Mission Computer Design Review
