I’ve been working on creating a new version of my IRIS Transmitter boards, which I use for high altitude balloon trackers. This was somewhat more of a re-architechture from the 1.0 and 1.1 revisions.
Revision 1.2 brings a number of changes:
- A new radio chip, the SI4464, replaces the ADF7012. The SI4464 provides more stable output power than the ADF7012 which had significant variations, and has a number of built in digital packet processing capabilities.
- The microcontroller is now run on 3.3V instead of 5V which allows the boost regulator to operate more efficiently when operating from two AA batteries.
- A uBlox MAX-6 GPS chip and antenna have been put on the board to remove the need for an external GPS device.
- Output power is reduced from ~250mW to 100mW. The lower power level is still plenty to serve the needs with the perfect line of sight of the high altitude flights, and reduces board complexity by removing the external RF FET amplifiers featured on previous revisions.
- Overall board size was again reduced.
