Fig 1.
Low power hardware design of the TickTag.
The microcontroller (B) manages the power states of the GPS module (C) via an electronic load switch (D) and a separately controlled backup power line. The EEPROM memory (F) is powered by a microcontroller pin and therewith requires energy only when reading or writing data. A green LED (G) gives visual feedback to the user (e.g., when the TickTag becomes activated). Data and configuration are accessible via a custom-designed user interface board (J) that can be connected to a computer or smartphone via USB (K).
Fig 2.
TickTag including housing example (A) and user interface (B). Here, the electronics (0.65 g) are powered by a 30 mAh lithium-polymer battery (0.55 g) and housed in a 3D-printed case (1.25 g), which can be replaced by Parafilm for weight reduction. The UIB can be connected to a computer or Android smartphone (via a USB OTG phone adapter) with the open-source TickTag app (B), allowing for tag configuration, data download and re-charging the battery.
Fig 3.
TickTag performance comparison of GPS sampling intervals at a stationary position in a suburban area.
Map data from OpenStreetMap (OpenStreetMap contributors, http://www.openstreetmap.org/copyright). Map tiles by Stamen Design, under CC BY 3.0.
Table 1.
Outdoor performance of the TickTag at a stationary position in a suburban area, operating on a 30 mAh lithium-polymer battery (total tag mass without housing: 1.2 g).
Fig 4.
Evaluation of short-term case study deployments of the TickTag on dogs (A) and on greater mouse-eared bats (B). We compared the TickTag GPS data of the anti-poaching hound with an e-obs mammal tag that was attached to the same collar (A). Map data from OpenStreetMap (OpenStreetMap contributors, http://www.openstreetmap.org/copyright). Map tiles by Stamen Design, under CC BY 3.0.