Weirdlab has been building GPS loggers for some time but they seemed to lack autonomy and other features. So he came up with next version of logger which is lightweight and portable. The core is based on Teensy 2.0 – Atmega32U4 based Arduino. The GPS module PA6B is small enough to squeeze everything in to small PCB.
Module is powered using BlackBerry Li-Ion 1100 battery. So there is a charging circuit included which is based on LTC4054-4.2 charger IC. The voltage from battery is stepped with LT1302 DC/DC converter. The main idea was to make LOG to be USB downloadable, so you wouldn’t need to pull out SD card. Arduino nature also gives easy way of updating firmware via Arduino IDE through USB port.