TMP117 ESP32 Web Server with ESP-IDF

This project demonstrates how to interface the TMP117 temperature sensor with an ESP32 microcontroller and display the temperature readings on a web interface.

The Texas Instruments TMP117 is a high-precision temperature sensor that provides 16-bit readings in Celsius.

Features

• Wi-Fi Connectivity: Connects the ESP32 to a specified Wi-Fi network.
• HTTP Web Server: Serves a minimal webpage displaying raw and compensated sensor values.
• TMP117 Sensor Integration: Using I2C for sensor communication and reading environmental sensor data.
• Efficient URL Handling: Serves the main webpage at / and efficiently drops invalid URL requests (e.g., /favicon.ico) without logging unnecessary errors.

Usage

1. Connect your ESP32 to the I2C pins of the TMP117 sensor:

• SDA: GPIO21
• SCL: GPIO22

2. Once connected to Wi-Fi, open a browser and navigate to the IP address displayed in the serial monitor.

3. View the webpage to see live raw and compensated temperature readings.

Dependencies

• TMP117 Sensor: I2C-compatible environmental sensor https://www.ti.com/product/TMP117
• ESP32 SOC: https://www.espressif.com/en/products/socs/esp32
• ESP-IDF: v5.3.2 or newer https://github.com/espressif/esp-idf

Detailed Description

TMP117 Driver Logic

The TMP117 driver is adapted from SparkFun TMP117 Arduino C++ Library TMP117 Arduino C++ Library. TMP117 Arduino C++ Library high-level functionality for accessing sensor data via I2C.

In this project:

• Bosch's i2c.h (C++) is replaced by ESP-IDF's i2c_master.h (C).
• Functions such as bme280_read_raw() and bme280_calculate() implement low-level I2C operations and data compensation using ESP-IDF.

tmp117_read_raw()

• Reads raw temperature data from the sensor.
• Sends I2C commands using i2c_master_transmit() and receives data using i2c_master_receive().

tmp117_compensate()

• Performs compensation of raw data using formulas provided in Texas Instruments TMP117 documentation.
• Implements temperature, pressure, and humidity compensation calculations for real-world accuracy.

Wi-Fi Connection

• Configured in wifi_init() using esp_wifi_set_mode() and esp_wifi_set_config().
• Connects to a predefined Wi-Fi SSID and password.
• Logs the assigned IP address for accessing the web server.

Web Server

• Hosted at the root URL /, serving an HTML page with raw and compensated sensor values.
• Handles invalid requests (e.g., /favicon.ico) by silently dropping them to minimize load and logging.

Webpage Parameters

• Endpoint: /
• Response: HTML page with:
  • Raw temperature value.
  • Compensated temperature (in Celsius).

Error Handling

• Unused or invalid requests are ignored without returning HTTP 404 responses.
• Reduces server overhead for invalid URL requests.

Setup

1. Clone the repository:

git clone <repository_url>
cd tmp117-esp32-web

2. Configure the Wi-Fi credentials by updating the following lines in main/main.c:

#define WIFI_SSID "YourSSID"
#define WIFI_PASS "YourPassword"

3. Set I2C configuration parameters at components/tmp117/tmp117.h:

#define I2C_MASTER_SCL_IO 22
#define I2C_MASTER_SDA_IO 21
#define I2C_MASTER_FREQ_HZ 100000
#define TMP117_ADDR 0x48

4. Build the firmware:

idf.py build

5. Flash the firmware:

idf.py -p /dev/ttyUSB0 flash

6. Monitor the serial output:

idf.py -p /dev/ttyUSB0 monitor

References

Hardware

• https://www.ti.com/product/TMP117
• https://www.espressif.com/en/products/socs/esp32

Copyright Notice

Copyright (c) 2024 Péter Vámos

https://github.com/pvamos [email protected] https://linkedin.com/in/pvamos

SparkFun TMP117 Arduino Library

• This software's Texas Instruments TMP117 sensor handling is based on SparkFun TMP117 Arduino Library (copyright (c) 2016-2023), published and available at: https://github.com/sparkfun/SparkFun_TMP117_Arduino_Library
• Distributed under the MIT License, which is included in the original repository: https://github.com/sparkfun/SparkFun_TMP117_Arduino_Library/blob/master/LICENSE.md and in this repository in the LICENSE_TMP117 file.

SparkFun TMP117 Arduino Library is a reference implementation of functionality for accessing TMP117 sensor data via I2C or SPI. SparkFun's i2c.h (C++) TMP117 I2C usage pattern has been re-implemented using ESP-IDF's i2c_master.h (C).

Espressif Systems ESP-IDF framework

This software also uses the ESP-IDF framework, created and maintained by Espressif Systems (Shanghai) Co., Ltd., published and available at:
https://github.com/espressif/esp-idf
ESP-IDF is distributed under the Apache License 2.0, which is included in its repository: https://github.com/espressif/esp-idf/blob/master/LICENSE and in this repository in the LICENSE_ESP-IDF file.

MIT license

This version includes modifications and re-implementation by Péter Vámos in 2024, published and available at: https://github.com/pvamos/tmp117-esp32-web

I publish my own work under the MIT License.

License

MIT License

Copyright (c) 2024 Péter Vámos [email protected] https://github.com/pvamos

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.