Mode ISM sensors

ISM sensors: weather stations, TPMS, remotes and meters around you (the rtl_433 idea).

Group	IoT & sensors
Default frequency	433.92 MHz
Default sample rate	2 Msps
In the mode list	Sensors, 433 / 868 MHz

Step-by-step: Tutorial-ISM-sensors

What ISM sensors is

Weather stations, tyre pressure sensors, remote controls and meters transmit short packets on 433, 868 and 915 MHz that a software-defined radio can read.

Frequencies and settings

433.92 / 868 / 915 MHz devices (the rtl_433 idea).

Setting	Value
Start frequency	433.92 MHz
Tuning range of the mode table	300 to 930 MHz
Sample rate asked	2 Msps
Lowest working rate	1 Msps
Channel width	1.6 MHz

OnAir takes any frequency you type; the numbers above are the mode's starting point and the range its table describes. In the app the shortcut label is Sensors, 433 / 868 MHz.

What OnAir shows

Weather stations, tyre pressure sensors, remotes and energy / water meters (wireless M-Bus header), and Z-Wave R1 / R2 / R3 (ITU-T G.9959: Home IDs, nodes, command classes; passive receive only, S0 and S2 traffic stays encrypted and is never decrypted): a device table with history, a Z-Wave view grouped by Home ID, a live log, unknown signals with their pulses.

The mode's own tab has these screens: Devices, Log, Unknown, Supported, Z-Wave, Sigfox. The other tabs (Overview, Receiver, Scan, History) are described on the Main window page.

Tips and caveats

• Checked with generated signals and impairments; recordings of real signals welcome.
• Which radio: Usually yes for narrowband signals: an RTL-SDR tunes roughly 24 MHz to 1.7 GHz at up to about 2.4 Msps. Wide signals such as TV channels need a faster radio, and OnAir says next to the source what the selected radio can do.
• Try it without a radio: most modes include a built-in synthetic test signal, so you can open the screen and try the controls first.
• Receiving and the law: This mode is passive. It only receives, never connects, pairs or joins networks, and never decrypts payloads. Check the rules where you live. See Legal.

Related pages

• All modes, IoT & sensors
• Supported radios, Troubleshooting, FAQ
• More in IoT & sensors: LoRaWAN, Meshtastic, MeshCore, Bluetooth LE, Zigbee / 802.15.4, Wi-Fi HaLow (802.11ah), ANT+ sensors, DECT cordless phones, Wi-SUN FAN, LoRa (raw), Wi-Fi networks