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| Spec | Value |
|---|---|
| Make | Inkbird |
| Model | ITH-20R |
| User Manual | https://pmod79883-pic31.websiteonline.cn/upload/2011 |
| Sampling Period | 10s |
Transmission Frequency | 433MHz |
| Transmission Distance | ≈300 Feet |
Our Signal
Using CubicSDR we can see our signal which happens every 80 seconds or so.
Building RTL-433 on Mac
Clone repository
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$ rtl_433 rtl_433 version 19.08-18-g8eecdbb branch master at 201909241811 inputs file rtl_tcp RTL-SDR Use -h for usage help and see https://triq.org/ for documentation. Trying conf file at "rtl_433.conf"... Trying conf file at "/Users/john.mehan/.config/rtl_433/rtl_433.conf"... Trying conf file at "/usr/local/etc/rtl_433/rtl_433.conf"... Trying conf file at "/etc/rtl_433/rtl_433.conf"... Consider using "-M newmodel" to transition to new model keys. This will become the default someday. A table of changes and discussion is at https://github.com/merbanan/rtl_433/pull/986. Registered 108 out of 138 device decoding protocols [ 1-4 8 11-12 15-17 19-21 23 25-26 29-36 38-60 63 67-71 73-100 102-103 108-116 119 121 124-128 131-138 ] Found Rafael Micro R820T tuner Exact sample rate is: 250000.000414 Hz [R82XX] PLL not locked! Sample rate set to 250000 S/s. Tuner gain set to Auto. Tuned to 433.920MHz. pulse_FSK_detect(): Maximum number of pulses reached! pulse_FSK_detect(): Maximum number of pulses reached! pulse_FSK_detect(): Maximum number of pulses reached! pulse_FSK_detect(): Maximum number of pulses reached! of pulses reached! |
Googling Error
The error means the program is apparently receiving a very long FSK encoded signal with more bits/pulses than any currently known devices. However the Ambient sensors are nor FSK encoded, but OOK encoded instead. A likely cause is that your sensors are now sending their signal at the same time, disturbing the transmission of each other. As the sensors send at slightly different frequencies it is received as something that might look like a FSK encoded signal. It will happen as the periodic transmission from the sensors drift slightly and becomes overlapping, and it will disappear again as the timing drift further.
Using Pulse Analyser with all protocols disabled:
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rtl_433 -A -R 0
rtl_433 version 19.08-18-g8eecdbb branch master at 201909241811 inputs file rtl_tcp RTL-SDR
Use -h for usage help and see https://triq.org/ for documentation.
Trying conf file at "rtl_433.conf"...
Trying conf file at "/Users/john.mehan/.config/rtl_433/rtl_433.conf"...
Trying conf file at "/usr/local/etc/rtl_433/rtl_433.conf"...
Trying conf file at "/etc/rtl_433/rtl_433.conf"...
Disabling all device decoders.
Consider using "-M newmodel" to transition to new model keys. This will become the default someday.
A table of changes and discussion is at https://github.com/merbanan/rtl_433/pull/986.
Registered 0 out of 138 device decoding protocols [ ]
Found Rafael Micro R820T tuner
Exact sample rate is: 250000.000414 Hz
[R82XX] PLL not locked!
Sample rate set to 250000 S/s.
Tuner gain set to Auto.
Tuned to 433.920MHz.
Detected OOK package 2019-10-02 12:21:20
Analyzing pulses...
Total count: 1, width: 1465.40 ms (366351 S)
Pulse width distribution:
[ 0] count: 1, width: 1465404 us [1465404;1465404] (366351 S)
Gap width distribution:
Pulse period distribution:
Level estimates [high, low]: 15892, 6
RSSI: -0.1 dB SNR: 33.6 dB Noise: -33.7 dB
Frequency offsets [F1, F2]: 19756, 0 (+75.4 kHz, +0.0 kHz)
Guessing modulation: Single pulse detected. Probably Frequency Shift Keying or just noise...
Detected OOK package 2019-10-02 12:22:41
Analyzing pulses...
Total count: 1, width: 1465.44 ms (366359 S)
Pulse width distribution:
[ 0] count: 1, width: 1465436 us [1465436;1465436] (366359 S)
Gap width distribution:
Pulse period distribution:
Level estimates [high, low]: 15921, 5
RSSI: -0.1 dB SNR: 34.2 dB Noise: -34.4 dB
Frequency offsets [F1, F2]: 20432, 0 (+77.9 kHz, +0.0 kHz)
Guessing modulation: Single pulse detected. Probably Frequency Shift Keying or just noise...
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Recording Signal using URH
Data:
00000000000000000000005555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555dfdf7f7f7df5f7f7f7dfdf5f5d7d7dfdf7d7d7df5fff7dfdfdf7f7f7ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff [Pause: 4836469 samples]
0000000000000000000000aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaeeaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaabaaaaaaabaabaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa2dd4d3910f0001000160bf37bc00b700540288510 [Pause: 3987304 samples]
Notes:
PreAmble
0's followed by 5's
dfdf7f7f7df5f7f7f7dfdf5f5d7d7dfdf7d7d7df5fff7dfdfdf7f7f7
followed by f's
PAUSE
0's followed by a's
2dd4d3910f0001000160bf37bc00b700540288510
PAUSE
Data:
| Iteration | After 5's | After a's | IN Temp | IN Humidity | OUT Temp | OUT Humidity | EXT Temp |
|---|---|---|---|---|---|---|---|
| 1 | 66.7 | 47 | 67.1 | 56 | 65.6 | ||
Another Recording
Other Tests of RTL_433
RadioHead ASK code on ESP8266 Board (Lolin/Wemos mini)
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Tuned to 433.920MHz. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Waveman Switch Transmitter id : A channel : 4 button : 3 state : off _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Akhan 100F14 remote keyless entry ID (20bit): 0x151 Data (4bit): 0x1 (Lock) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Waveman Switch Transmitter id : A channel : 4 button : 3 state : off _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Akhan 100F14 remote keyless entry ID (20bit): 0x151 Data (4bit): 0x1 (Lock) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Waveman Switch Transmitter id : A channel : 4 button : 3 state : off _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Akhan 100F14 remote keyless entry ID (20bit): 0x151 Data (4bit): 0x1 (Lock) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Waveman Switch Transmitter id : A channel : 4 button : 3 state : off _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Akhan 100F14 remote keyless entry ID (20bit): 0x151 Data (4bit): 0x1 (Lock) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Waveman Switch Transmitter id : A channel : 4 button : 3 state : off _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Akhan 100F14 remote keyless entry ID (20bit): 0x151 Data (4bit): 0x1 (Lock) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Waveman Switch Transmitter id : A channel : 4 button : 3 state : off _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:58 model : Akhan 100F14 remote keyless entry ID (20bit): 0x151 Data (4bit): 0x1 (Lock) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:59 model : Waveman Switch Transmitter id : A channel : 4 button : 3 state : off _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:59 model : Akhan 100F14 remote keyless entry ID (20bit): 0x151 Data (4bit): 0x1 (Lock) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:59 model : Waveman Switch Transmitter id : A channel : 4 button : 3 state : off _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:59 model : Akhan 100F14 remote keyless entry ID (20bit): 0x151 Data (4bit): 0x1 (Lock) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:59 model : Waveman Switch Transmitter id : A channel : 4 button : 3 state : off _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:59 model : Akhan 100F14 remote keyless entry ID (20bit): 0x151 Data (4bit): 0x1 (Lock) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:59 model : Waveman Switch Transmitter id : A channel : 4 button : 3 state : off _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ time : 2019-10-02 09:13:59 model : Akhan 100F14 remote keyless entry ID (20bit): 0x151 Data (4bit): 0x1 (Lock) |
References
| Reference | URL |
|---|---|
| User Manual | Inkbird ITH-20R.pdf |
| Inkbird ITH-20R | https://www.ink-bird.com/products-data-logger-ith20.html |
| RTL-SDR: 433.92Mhz ASK/OOK Decoding of Various Devices with rtl_433 | https://goughlui.com/2013/12/20/rtl-sdr-433-92mhz-askook-decoding-of-various-devices-with-rtl_433/ |
| RTL_433 | https://github.com/merbanan/rtl_433 |
| Building RTL_433 | https://github.com/merbanan/rtl_433/blob/master/docs/BUILDING.md |
| Frequency Shift Keying | https://en.wikipedia.org/wiki/Frequency-shift_keying |