Equipment / Test Setup

1. Raspberry Pi running MQTT Broker (connected to LAN via WIFI)
2. Arduino Uno With Wifi and a breakout board with LED
3. Linux Mint with:
    Node-RED
    MQTT Explorer
    Python3 MQTT subscribe and publish scripts
4. Windows PC with Arduino IDE

Note:
1. The applications on Linux and the PC can be combined and run on either machine.
2. An ESP32 (microcontroller) can be used instead of an Arduino.

Tests

Initially run the tests with one IoT device. Next, use multiple IoT devices (servo motors, LEDs, ...).

Suggested MQTT Topic and Messages

MQTT Topic	MQTT Message	Action
test/wifi/iot-01	on	turn on LED
test/wifi/iot-01	off	turn off LED
test/wifi/iot-01	blink	blink LED on and off
test/wifi/iot-01	blink on-duration [off-duration]	turn LED on for on-duration seconds and off for off-duration seconds if no off-duration is specified, it defaults to on-duration

Test #1 verify Python3 MQTT subscribe and publish

Step	Equipment	Action
1	Linux Mint	run Python MQTT publish and subscribe scripts
2	Linux Mint	verify published messages
3	Linux Mint	verify subscriptions with MQTT Explorer

Note: Node-RED can also be used as MQTT publisher and subscriber.

Test #2 find Arduino's MAC address

Step	Equipment	Action
1	Arduino	connect Arduino to a PC USB port
2	PC	start Arduino IDE and its serial monitor
3	Arduino	load appropriate sketch
4	Linux Mint	check serial monitor for Arduino MAC address

Test #3 verify Arduino connection via WIFI

Step	Equipment	Action
1	Arduino	load appropriate sketch (Arduino connected to PC USB port) (then disconnect from USB)
2	Arduino	connect Arduino to independent power supply (no USB connection)
3	LAN Router	check LAN router for device connections

Test #4 verify Arduino connected via WIFI can MQTT publish

Step	Equipment	Action
1	Arduino	load appropriate Arduino sketch (publish to MQTT topic) (then disconnect from USB)
2	Linux Mint	run Python3 MQTT subscriber
3	Arduino	connect Arduino to independent power supply (no USB connection)
4	Arduino	publish messages MQTT on a loop
5	Linux Mint	verify subscriber receives messages

Note: Node-RED can also be used as MQTT subscriber for this test.

Test #5 verify Arduino connected via WIFI can subscribe to MQTT topic

Note: the Arduino should be connected to the LED on the breakout board

Step	Equipment	Action
1	Arduino	load appropriate Arduino sketch (subscribe to MQTT topic) (then disconnect from USB)
2	Arduino	connect Arduino to independent power supply (no USB connection)
3	Linux Mint	run Python3 MQTT publisher
4	Arduino	when MQTT messages received, blink the LED in various patterns specified by the message

Note: Node-RED can also be used as MQTT publisher for this test.