Anthony Stirk – a member of The Register’s Low Orbit Helium Assisted Navigator (LOHAN) project – has designed a sleek miniature tracker powered by Atmel’s ATmega328P microcontroller (MCU).
Dubbed Pava 9, the platform was inspired by Stirk’s goal to create the lightest tracker possible, with a run time suitable for long-distance High Altitude Ballooning (HAB) flights.
“The heart of the tracker is [Atmel’s] ATmega328P microcontroller as favored by the Arduino Uno, however in this guise it’s underclocked running at 2MHz to help with power consumption,” Stirk told Lester Haines of The Register.
“A snap-off programming header reduces the overall weight to 2.5g. Connected to the board is a u-blox MAX7C GPS module. The whole thing runs at 1.8V and can be powered either by a separate step-up or a LiPo+solar charger board… Power savings over the previous board are quite significant, giving 40 per cent more run time.”
According to Stirk, the original Pava utilized an off-the-shelf RFM22B radio transmitter, which experienced a number of issues with frequency drift due to temperature. Plus, it lacked support for modes such as DominoEX and THOR.
“[So] I decided to make a custom radio for this tracker based around SI’s 4060 transmitter chip. Making it myself meant I could choose all the components and ensure they work at the lower temperatures,” he explained.
“A TCXO (temperature-compensated crystal oscillator) ensures a stable frequency. The choice of frequency, although out of spec for the radio module, opens up the board to doing MFSK DominoEX and THOR modes.”
Before launching stratowards aboard the Vulture 2, the PAVA 9 is scheduled to relay telemetry during LOHAN’s “Punch” and “Judy” upcoming test flights.