/esp32-greengrass-temperature-sensor

ESP32 project to publish the current temperature and humidity (from a DHT11 sensor) to AWS IoT via Greengrass

Primary LanguageCApache License 2.0Apache-2.0

esp32-greengrass-temperature-sensor

ESP32 project to publish the current temperature and humidity (from a DHT11 sensor) to AWS IoT via Greengrass.

This can then be streamed to a DynamoDB table via IoT rules, and entries automatically aged off using the TTL field in the payload.

Payload

The ESP32 will send the following payload to Greengrass:

{
  "DeviceID": "ESP32-temperature",
  "timestamp": 1598798739,
  "tempC": 25.6,
  "Humid": 30,
  "TTL": 1599057939
}
  • DeviceID - the device ID as configured in AWS and config.h
  • timestamp - epoch timestamp of the message
  • tempC - reported temperature (°C) from the DHT11
  • Humid - reported % humidity from the DHT11
  • TTL - epoch TTL timestamp for use with DynamoDB TTL

Usage

  1. Clone the repo.
  2. Follow the initial setup instructions at https://github.com/aws-samples/arduino-aws-greengrass-iot. You will need to have setup the libraries, created a Greengrass group, deployed a Core that is accessible from the network that the ESP32 will connect to, and created a Device for the ESP32.
  3. Copy and modify the example config files to the root of the project. 
    cp config-examples/* ./
mv aws_certificates-example.c aws_certificates.c
nano aws_certificates.c
mv config-example.h config.h
nano config.h
  4. Connect your DHT11 sensor to your ESP32. Note that if you are using pin #12 for data, you will need to disconnect it during program upload to avoid communication errors.
  5. Compile and deploy to the ESP32 via the Arduino IDE.

Acknowledgements

This project is heavily based in the sample ESP32 Greengrass publish example by AWS, and uses the Arduino AWSGreengrassIoT Library. See NOTICE for copyright information.