Simple device control using MQTT

This example demonstrates how to perform remote device control over MQTT protocol. Build & flash a firmware and configure WiFi (see quick start guide), and configure MQTT server:

mos build --arch esp8266
mos flash
mos config-set wifi............
mos console

Then use an MQTT client to send messages, for example web-based client at http://www.hivemq.com/demos/websocket-client/. Click on "Connect", then "Add new topic subscription", choose topic /response, then publish a message. In the "Topic" field, specify /request, and in the "Message" field, one of the following:

• {"gpio": {"pin": 2, "state": 0}} - sets GPIO pin X into state Y
• {"button": {"pin": 0}} - start listening on button presses on GPIO pin X. When button is pressed, a message "click" is sent to the /response topic
• {"i2c_write": {"data": "af404c"}} - write byte stream to the I2C bus. In this example, there are 3 bytes 0xaf 0x40 0x4c. First byte is an I2C address. Status code 0 in response means success, all other codes mean failure.

By default, this firmware connects to the broker.mqttdashboard.com:1883 MQTT server. You can change this default setting by editing src/conf_schema.yaml file and rebuilding/reflashing the firmware. Alternatively, you can change any setting on the fly, for example to choose a different MQTT server:

mos config-set mqtt.server=my_server:my_port

How to use Amazon IoT with this example

First, download the Amazon's aws utility and run aws configure. Then you're ready to onboard

... build, flash, configure wifi
mos aws-iot-setup --aws-iot-policy YOUR_POLICY
mos console

Login to AWS IoT console, use web-based MQTT client to send messages. See https://mongoose-os.com/blog/esp8266-remote-control-via-aws-iot/ for the step-by-step instructions.