Design of a memory-card based low-cost GPS data-logger for livestock monitoring

This work presents details of a memory card based open-source, low-cost and low power solution for long-term monitoring of grazing livestock. The described global positioning system (GPS) based data logger node weighs 150g (including D-size battery of 3.6V and 13AH and a casing with dimensions of 10 × 7.5 × 3.5 cm). With a memory card of 4GB, it can record geo-coordinates for 248 days (4 readings per day), with bill of materials less than 150 USD. Earlier open-source works based on VHF radio tracking and other commercial devices cost above 1000 USD and are not customizable. This work presents the hardware design and trial data obtained from a grazing sheep in the northern Himalaya, Pakistan. The solution is relevant for applications where data-loggers are easy to retrieve.