Now for the telemetry controller. Needed was a low power micro MCU AVR that could be used to setup and program the radio and also be smart in how it operated with the ability to also go into sleep mode and consume virtually no power. I used a SEEED XIAO for the initial proof of context and was wondering if I could use an Atmel ATTINY85 so going minimalistic, gave it a successful try, however I ran out of IO pins as we needed a way to switch it all on when in use and off when in storage via a hall magnetic sensor as switch. This meant we needed to reprogram an IO pin to act as power switch sensor when the radio was not transmitting and quickly reprogram it again when it was time to transmit. A way to indicate whether it was on or off via a LED also needed a separate IO pin. After getting the IO pin interupt dance routines in place, the specs were changed, so this design will remain a basic TX only falconry telemetry transmitter. The 'what if' and 'how about' were laid on the table.
With time came new ideas to make the project smarter (and bigger). First idea was to monitor battery charge and take appropriate action. This can also be done with the ATTINY, but not comprehensively with complex rechargeable batteries. Then the word GPS was mentioned as an option which came with many possibilities and benefits, but also some drawbacks. Last but not least, as we are using a transceiver that can transmit and also receive, the option to remotely send instructions to the telemetry unit to change settings (like GPS On/Off, low or high power) while it is in operation was put on the list. Not to forsake the concept of a simple telemetry transmitter, an expandable modular approach was adopted. All that needed to change was the MCU, as it could not potentially service the new needs. The ATTINY85 got replaced by a bigger brother, the ATMEGA328 now we have enough IO pins, can accommodate GPS, do accurate battery management, implement two way RF communication and also consider it being used as APRS transmitter (if operated by a radio amateur license holder) for wide area geo-location in the future.
New concept (May 2022) for long distance and 'odd' situation tracking. Fact: a bird flying at 'high' altitude is easy to track from the ground in line of sight. Fact: a bird on the ground is difficult to track from the ground because of obstacles (buildings, natural growth, distance, rf echo's, etc.). Challenge: can we reverse this and send a drone into the sky with a tranceiver to scan the surface below for transmissions, interact with the telemetry transponder and relay this to a base station. Have not even got the components I need for the simple telemetry transponder and already I know we need asmart telemetry receiver as well. Work to done while we wait.