Smart Falconry Telemetry - Small low power MCU controlled RF telemetry transceiver for tracking small wildlife and birds of prey on the wing.

Falconry Telemetry, from concept to prototyping to reality.

" Falconry telemetry transmitters are generally a large investment for falconers. This is because the market for ultra light weight transmitters that are powerful yet consume minimal current is relatively small. It also takes a lot of engineering to create a powerful transmitter in a micro package light enough to attach to a small bird of prey. The worst that can happen to a falconer is when the bird of prey flies away, cannot be tracked right away because of geography (think flying over a large river, etc.) or the time of day (with a setting sun) and the transmitter battery is starting to get low. Without an active transmitter the chance of locating the bird is lost as they can fly any direction any time. Not only is the bird lost, but also the telemetry transmitter, a double sour deal. After seeing this happen much to often, the time was ripe to come up with cost effective and efficient alternative with adaptable options for different operational modes.

Looking into using discreet SMD components which are easy for creating very small size circuits using a few transistors, capacitors and resistors soon got dropped. The reasons are, it uses to much energy, continually consuming current, even when not transmitting and the frequency stability is not acceptable. The second idea was to use a MCU with a micro small xtal transmitter module. A proof of concept using a SEEED MCU with a (common) miniature fixed frequency module soon became obsolete as the telemetry receiver at Falconcrest falconry can only receive 433.1XX MHz.

A low cost to preferably no cost project

With no budget it meant using bits and pieces lying around and thinking twice about ordering any components or having anything constructed. A tall order for a micro transmitter. I am thinking of making this an open source project should others be interested on using and improving this wild life telemetry design.

Functional specifications, research,design and development

The 'must have' requirements were: 1. small, 2. lightweight, 3. long range transmitter, 4. long operational period on a limited lifespan battery, 5: Terranean weather proof, 6: Animal vandal proof. That is quite a challenge as some requirements have a lot of impact on other requirements. The way to tackle this was to look at the possibility of making it really dynamic by allowing multiple implementation like using different interchangeable battery types and providing a means to instruct the transmitter which mode you want, like long battery life, or high power transmission. Thus a micro radio transceiver and a means to control it was needed.

Searching for a powerful very diverse micro RF transceiver module, not like the fixed frequency unit I first tested, I came across the Silicon Labs Si4463 SMD chip, the spec sheet showed a +20db transmitter with a frequency range of 142 to 1050 MHz. Just what was needed to service nearly all falconry telemetry receiver types frequency ranges as well as powerful enough to get excellent transmission range. It supports (tested) stable frequency transmissions on a variable power supply (battery being used) and supports 'sleep mode' where it uses virtually no power at all. Proof of concept showed that indeed, this very small RF transceiver although initially complex to program and setup could run on a CR2023 button cell at full power using on off keying at one second intervals for nearly 2 weeks (309 hours).

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.

Active project

This is an active project under development as spare time allows, it is a hobby after all. More information will be made available as results are achieved.

Results so far:

• Operating voltage: 1.8v to 3.8v (lowest 1.8v = AVR MCU running at 1 MHZ, highest 3.8v = Radio, anything above may damage it)
• 12/03/2022: Waiting for ordered components to arrive.
• 1/04/2022: The SMD RGB LEDs, Hall effect sensors and SMD resistors have arrived. Still waiting on more parts. The pandemic and global resource shortages, not to forget the impact of the Russian attack on Ukraine, has big impact on supply chains. This is very noticeable at present.

• 20/04/2022: MCUs (5) for the smart falconry telemetry unit have arrived. Very poorly packaged, but appear to be intact
• 21/04/2022: SMD capacitors (0603,0805 and 1206) have arrived, still waiting on some active components to arrive.

RF transmitters, rules and regulations (as proclaimed in 2022 : Agenschap Telecom NL the local authority at present)

• Transmissions in the 144 MHz (2 meter band) by unlicensed parties for this frequency range and limited by:
  • Maximum power of 100 mW (supplied to fixed antenna).
  • Fixed antenna ([not removable],don't want antennas with any gain being attached)
• If complaints are received from Amateur radio operators (interference) then it must be shut down and stopped.

Got that out the way. Considering there is always a licensed Amateur Radio Operator (PD9JS) around, another 'rule (law)' states that anyone can operate amateur radio equipment (on any legal (for that operator) frequency, power level and modulation mode) if under the supervision of a licensed radio amateur operator. Thus activating APRS and using it to track my feathered friends with the help of the local APRS HAM community should not be a problem. A radio amateur license is not that hard to get.and you need it if you're going down the APRS route on 144.800 MHz (Europe). Search for a local HAM radio group near you and get connected and involved.

Considerations for success

This is the first serious real world full stack project (by full stack is meant: hardware, firmware and software) being done after 30 years of inactively as an electronic engineer and technician. Much has changed since then, and knowing the devil is in the details, the footprints of the printed circuit board as well as the pinouts of the components need to confirmed prior the manufacturing the PCBs.

The printed circuit boards are the most expensive investment of this 'no budget' project and will be even more expensive is a redesign of an already made PCBs is required. For this reason all 'Bill Of Materials' components need to be physically available to enable checking that the footprints on the PCB ares correct and that the electrical connections are conform to the component designated pinouts. Hence the wait for all electrical and electronic components to be available physical (size) and electrical (pinout functionality) confirmation.

Progress on manufacturing

• 21/06/2022: As promised the PCBs manufactured by JLCPCB have been delivered (vacuum sealed with a dehumidifier) on time and at a very reasonable price (for a no budget project), thus a definite recommendation for PCB manufacturing and an address I am sure to use again in future!
• 21/06/2022: Important note to self: Still waiting for components from 'Aliexpress' who for the last two months have been claiming things have been delivered while they are not and marked orders as completed! Thus next time factor in that suppliers can go bad and prepare to order components locally at a higher price, is a better deal than paying money for nothing never delivered and you have no recourse. Lesson learned! Any sponsors? Moving on.

Currently busy with another project that should take another two weeks and then the art of soldering the available components on the first test boards begins...

Progress.. Zero at present

• 23/07/2022: Trying to make ends meet! There is no time available at present. In a society where I must pay commercial businesses to be able to pay my government tax, fast rising uncontrolled inflation, I must pay my bank (they finally have us all) to be able to put my cash in "the system" interest rate NEGATIVE! and do any transactions. Fuel prices through the ceiling, a government that does nothing and everything according to media is caused by the war that Russia started. Leaves me with little time for projects.
• 23/07/2022: Even Aliexpress has gone bad claiming things delivered while nothing received (5 times in a row) = other source required. Moral to the story: Need time to ensure continuation on other levels... I will be back (soon)