I built this APRS tracker with the idea to use it in Iceland for my DXpedition. In the end we did not used it because the planned car for the expedition (where it was planned to be installed) was not ready on time.
This tracker is composed from:
- 1 Arduino MEGA
- 1 Raspberry PI
- 1 Signalink sound card interface
- 1 Baofeng UV-5R VHF/UHF transceiver
- 1 Diamond VHF vertical antenna
- 1 Relay board
- 2 step up/down converters
The first step down converter is used to power the arduino with 7 volts. The arduino controls the relay board and one of its ADC receive the battery voltage.
After 15 seconds the arduino power on the raspberry pi (via the relay board and another step down converter configured on 5v) and waits for order via the USB port.
When starting, the rasberry pi send the order to the arduino to power on the transceiver and start direwolf (the software to encode the AX25 packets). APRX is used for the iGate software and then start to send/receive packets (via direwolf , the signalink and the baofeng transceiver).
Each minute the voltage of the power supply is checked and if the voltage is under a defined value (at the moment 12.1V) the raspberry send the order to the arduino to shutdown the power (with a delay of few seconds) and initiate itself a shutdown. After the shutdown, the system remains in this low power consumption mode until the battery die or a power cycle.
At the moment a 12V power supply is used to power on the system. I was able to run it for 24 hours from a 100Ah battery. (until the 12.1V)