The original OpenTracker was discontinued when the Freescale MC908KX8 microcontroller ceased production.
OpenTracker Revision History
All circuit boards have the revision number printed on the board, usually in the lower right corner. The OpenTracker optionally came a translucent case, with several color choices, and was the only series to use a colored case.
Revision 1: This revision only had a few trackers (20-25) produced, and they did not have voltage measurement capability.
Revision 2: This revision had three variations, all marked "Rev 2". They differed only in the board manufacturer and some minor trace routing changes. Green circuit board.
Revision 3: This revision added a TTL-level carrier detect input, and featured an improved PCB layout. Black circuit board.
Revision 4: This revision replaced the 2N3904 transistors with 2N7000 FETs. A larger voltage regular was used, with a five volt output capability to power a GPS. Red circuit board.