This AVR Sensor Board V3 node has been built using a different voltage regulator, together with modified values for the battery sense resistor divider, to allow it to be powered directly by the car battery. It has a bi-directional serial connection to the existing car PC and zombie mode is entered (by sensing the 5V supply from the USB serial lead via a resistor divider) when the PC is not running.
Car Battery Monitoring
The node operates as a car battery voltage sensor regardless of zombie mode.
When not in zombie mode the node enables the RFM69 receiver and the serial connection to the PC. This allows the following features:
Location Updates
The car PC based APRS tracker is modified so that whenever it transmits an APRS position update it also sends a suitably formatted location string on the serial connection to the UKHASnet node. The node software then transmits this string as the payload of a UKHASnet format packet.
Repeater and Gateway
Received UKHASnet packets are sent to the PC, which gateways them to the Internet over a 3G connection and also displays them on the APRS tracker display. The node also acts as a repeater and will also gateway its own transmissions, thus providing battery voltage and location to the Internet.
