A python project to log to standard console the beeps per minute (BPM) of a Chick Timer (CT) for New Zealands endangered Kiwi. The console output will contain background BPM, Fast Telemetry (FT) numbers, Chick Timer (CT) data sequence, signal to noise ration (SNR), decibels full scale (dBFS) and finally Latitude/Longitude.
Currently the only way to decode these signals is to travel to remote parts of the bush and manually record the signal output. This is time consuming and if a predator is killing kiwi it may not be detected for several weeks. Kiwitracker allows for real time remote monitoring of signals and more granular data. A good video of the the terrain involved and the beeps emitted is on Fiordland Kiwi Diaries
It is intended that the project can be deployed on a Rasp Pi 5 in isolate kiwi territory with remote access. Also intended to be possible to drone mount the hardware and geo-locate Kiwi quickly by filtering GPS and dBFS data.
Kiwi trackers emit 10mW continuous wave (CW) beeps on one of 100 channels spaced evenly between 160.120Mhz and 161.110Mhz. A list of the channel numbers and corresponding frequencies is here.
Each beep is 0.017 sec long. By varying the time between beeps information is encoded in the signal in three different ways:
The transmitter is in this mode by default. By counting the number of beeps per minute the state of the bird can be determined:
- 80 BPM - Mortality mode
- 46-48 BPM - Not incubating
- 30 BPM - Incubating
Every 10 minutes the transmitter pauses for 3 seconds then emits 8 groups of two digit numbers. Each pair of two digit numbers is seperated by a 3 second pause.
- Days since change of state
- Days since hatch
- Days since desertion alert
- Time of emergence
- Weeks of batt life for Tx
- Activity yesterday
- Activity 2 days ago
- True mean of last 4 days (activity)
Modes 1 and 2 are easily decoded by listening to the received signal. FT mode can only be decoded by computer as it involved altering by 10ms the timing between beeps in both modes 1 and 2.
The fast telemetry format is five values repeating continuously. I synchronisation code either Mort, Nesting, Not nesting, Hatch or Desertion Alert. A sync value is always followed by two pairs of number XX XX.
Legal nominal pulse intervals in ms are 250, 750, 1250, 1750, 2000, 3000, 3750. The delay is added to all those intervals except 250ms which is only used for double pulsing. Attached is the user manual that gives the detail on how those intervals might be heard and what they mean. Double pulsing is defined as sets of 2 pulses split by 250ms with each set of 2 pulses separated by 1750ms (from last to first).
The First pair of numbers is always the days since the state (indicated by the sync code) started; Mort, Nesting, Not nesting, Hatch or Desertion Alert.
The second pair of numbers changes meaning depending on the state. Mort = Battery weeks of life remaining, Nesting = 4 Day mean of most recent activity data, Not nesting = Battery weeks of life remaining, Hatch = 4 Day mean of most recent activity data, Desertion Alert = Activity data last night. Activity data is in lots 10 min periods the bird was considered to be active in the previous 24hrs. So a value of 15 = 15*10=150min or 2hrs 30min.
Fast Telemetry table:
| Encoded Value | Pulse Delay(ms) | BPM | |||||
|---|---|---|---|---|---|---|---|
| 0 | 0 | 80 | 48 | 34.28 | 30 | 20 | 16 |
| Mortality | 10 | 78.95 | 47.62 | 34.09 | 29.85 | 19.93 | 15.96 |
| 1 | 20 | 77.92 | 47.24 | 33.89 | 29.70 | 19.87 | 15.92 |
| 2 | 30 | 76.92 | 46.88 | 33.70 | 29.56 | 19.80 | 15.87 |
| Nesting | 40 | 75.95 | 46.51 | 33.51 | 29.41 | 19.74 | 15.83 |
| 3 | 50 | 75.00 | 46.15 | 33.33 | 29.27 | 19.67 | 15.79 |
| 4 | 60 | 74.07 | 45.80 | 33.14 | 29.13 | 19.61 | 15.75 |
| Not Nesting | 70 | 73.17 | 45.45 | 32.96 | 28.99 | 19.54 | 15.71 |
| 5 | 80 | 72.29 | 45.11 | 32.78 | 28.85 | 19.48 | 15.67 |
| 6 | 90 | 71.43 | 44.78 | 32.60 | 28.71 | 19.42 | 15.63 |
| Hatch | 100 | 70.59 | 44.44 | 32.43 | 28.57 | 19.35 | 15.58 |
| 7 | 110 | 69.77 | 44.12 | 32.25 | 28.44 | 19.29 | 15.54 |
| 8 | 120 | 68.97 | 43.80 | 32.08 | 28.30 | 19.23 | 15.50 |
| Deserting | 130 | 68.18 | 43.48 | 31.91 | 28.17 | 19.17 | 15.46 |
| 9 | 140 | 67.42 | 43.17 | 31.74 | 28.04 | 19.11 | 15.42 |
Full manual http://wildtech.co.nz/downloads/NiB%20CT%20V3.4.pdf
- Add samples for testing purposes (weak signals, signals on ch00 and ch99, multiple signals, signals at 30, 48, 80 bpm, CT signals)
- In sample_processor handle edge case where chunk edge goes through middle of a beep (falling edge array is empty). Add Boolean 'no_falling_edge' and track number of high samples for calculation of
BEEP_DURATIONon next set of chunks. - Lower threshold to more suitable value - from 0.9 to ?
- Add sample signal on Ch00 and Ch99 for Nyquist edge test
- Add sample signal for 30BPM (incubation mode)
- Add validation (1) background BPM output with tolerance +/- 1?
[expected for expected in [80, 46, 47, 48, 30] if abs(actual - expected) < 1]and (2) BEEP_DURATION must be 0.017 sec - Processing of CT signals - start with a data class for CT and then CT detection (3 second pause in gap between beeps, i.e. rising_edges)
- Add SNR output for each beep
- Add option to log signals to MySQL
Installation within a virtual environment is highly recommended
pip install 'kiwitracker@git+https://github.com/bigalnz/test_fft.git'git clone git@github.com:bigalnz/test_fft.gitpip install -e .Once installed, the project can be invoked on the command line:
kiwitracker --helpWhich should display the following:
usage: kiwitracker [-h] [-f INFILE] [-o OUTFILE] [-m MAX_SAMPLES] [-c CHUNK_SIZE] [-s SAMPLE_RATE] [--center-freq CENTER_FREQ] [-g GAIN] [--carrier CARRIER]
options:
-h, --help show this help message and exit
-f INFILE, --from-file INFILE
Read samples from the given filename and process them
-o OUTFILE, --outfile OUTFILE
Read samples from the device and save to the given filename
-m MAX_SAMPLES, --max-samples MAX_SAMPLES
Number of samples to read when "-o/--outfile" is specified
Sampling:
-c CHUNK_SIZE, --chunk-size CHUNK_SIZE
Chunk size for sdr.read_samples (default: 65536)
-s SAMPLE_RATE, --sample-rate SAMPLE_RATE
SDR sample rate (default: 1024000.0)
--center-freq CENTER_FREQ
SDR center frequency (default: 160270968)
-g GAIN, --gain GAIN SDR gain (default: 7.7)
Processing:
--carrier CARRIER Carrier frequency to process (default: 160707760)