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LMT01 temperature sensor~

This feature is included only in tasmota-sensors.bin

Otherwise you must compile your build and define USE_LMT01.

The Texas Instruments LMT01 is 2-pin digital output temperature sensor that converts temperature directly to a sequence of digital pulses, reading a range from -50°C to +150°C with up to 0.5°C accuracy. It is available in a DIY-friendly small TO-92 package.

Connection is by a single GPIO to count the pulses, which needs a driver transistor to convert the small current changes into logic level voltage swings.

Limitations of current implementation:

  • Only the simple linear conversion is used. The datasheet suggests the use of a look-up table to improve the accuracy at the edges of the range, this is not yet implemented.
  • The sensor code only supports one LMT01 instance.

Configuration~

Choose a pin GPIOx. The GPIO can be connected to the LMT01 via a NPN transistor, so current pulses pull the GPIO line low: see Figure 32 in the LMT01 datasheet.

In the Configuration -> Configure Module page assign:

  • GPIOx to LMT01 Pulse

After a reboot the sensor will be detected and displayed. If the connection is not working, the pulse counting will timeout and you will see null displayed for the temperature.