https://github.com/import-tiago/lib-lmt01

LMT01 digital temperature sensor (Texas Instruments) – An Arduino-compatible library using a pulse-counting method and hardware timer.
https://github.com/import-tiago/lib-lmt01

arduino esp32 lmt01 lmt01-arduino lmt01-esp32 lmt01-library platformio sensor temperature temperature-sensor

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LMT01 digital temperature sensor (Texas Instruments) – An Arduino-compatible library using a pulse-counting method and hardware timer.

• Host: GitHub
• URL: https://github.com/import-tiago/lib-lmt01
• Owner: import-tiago
• Created: 2025-05-07T16:17:30.000Z (about 1 year ago)
• Default Branch: main
• Last Pushed: 2025-05-10T16:53:34.000Z (about 1 year ago)
• Last Synced: 2025-05-12T07:00:06.822Z (about 1 year ago)
• Topics: arduino, esp32, lmt01, lmt01-arduino, lmt01-esp32, lmt01-library, platformio, sensor, temperature, temperature-sensor
• Language: C++
• Homepage:
• Size: 1.81 MB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

          
# LMT01 Temperature Sensor Library (ESP32 + Arduino)

An Arduino-compatible library for the **ESP32** platform that interfaces with the Texas Instruments **LMT01** digital temperature sensor using a **pulse-counting** method and hardware timer.



  



## Key Features

- Works with ESP32 (Arduino framework)

- No analog pins required — digital pulses are counted instead

- Hardware timer-based measurement window

- Temperature output in Celsius

- Ultra-low power consumption: typically 34 µA to 125 µA during the temperature-to-digital conversion process.

- High accuracy: ±0.5 °C (–20 °C to 90 °C), ±0.625 °C (90 °C to 150 °C), ±0.7 °C (–50 °C to –20 °C)

## Basic Usage

```cpp

#include "LMT01.h"

#define LMT01_PULSES_PIN 41

#define LMT01_PWR_PIN 2

LMT01 sensor(LMT01_PULSES_PIN, LMT01_PWR_PIN, 130); // 130ms window

void setup() {

    Serial.begin(19200);

    sensor.begin();

}

void loop() {

    if (sensor.ready()) {

        float temp = sensor.read();

        Serial.printf("%.2f %cC\n", temp, 176);

    }

}

```

> Note: This library is designed specifically for ESP32 boards using the Arduino framework. It uses hw_timer_t and attachInterrupt for reliable pulse measurement.

## Basic Circuit

![LMT01 basic circuit](assets/circuit.png)

> Internal pull-up enabled by the library.

## Serial Output

![LMT01 serial output](assets/terminal.png)

> Temperature variation from an ambient temperature of around 25 °C up to approximately 60 °C (achieved by placing the sensor in contact with water preheated in the microwave for about 40 seconds).

# Concepts ([Datasheet](assets/LMT01.pdf))

## Time Window Definition

![LMT01 Time Window](assets/time_window.png)

## Transfer Function

The output transfer function is approximately linear and can be expressed as:

$$

\text{Temp} = \left( \frac{\text{PC}}{4096} \times 256^\circ\text{C} \right) - 50^\circ\text{C}

$$

Where:

- **PC** is the number of pulses counted within the defined time window.

- **Temp** is the resulting temperature in degrees Celsius.

## Compatibility

This library was tested with:

- **ESP32 Arduino Core v3.2.0**  

  Based on **ESP-IDF v5.4.1**  

  🔗 [GitHub Release: espressif/arduino-esp32 v3.2.0](https://github.com/espressif/arduino-esp32/releases/tag/3.2.0)

> For best results, ensure you are using this version or later of the ESP32 Arduino core.