Physical computing wireless tutorial - WiFi and MQTT with ESP32, Adafruit IO and IFTTT

Easy Arduino TX. How to push sensor or event data to a responsive dashboard and trigger tweets or other notifications

13b1 (basic principle) - auto connect/reconnect to WLAN router and MQTT broker with two functions; TX dummy data (random numbers)

13b2 (working prinicple) - auto connect/reconnect to WLAN router and MQTT broker with a state machine; TX dummy data (random numbers)

13b3 (fully working principle) - auto connect/reconnect to WLAN router and MQTT broker with a state machine; TX photoresistor values, TX momentary switch status; tweet alert via MQTT broker and IFTTT

Setup

You can click the image to play the associated YouTube video

Schematic

BOM

€ 14,00 Adafruit Metro Mini 328 5V 16MHz microcontroller
€ 19,00 Adafruit AirLift FeatherWing - ESP32 WiFi
€  2,00 CdS photoresistor
€  1,00 Tactile button momentary switch
€  4,00 Half-size transparent breadboard
€  2,00 Breadboard mini modular black
€  1,00 Jumper cables
€  1,00 2,1mm DC barrel-jack
€  2,00 1µF & 100 µF 10V el. caps, 4,7kΩ resistor
€  3,00 DURACELL Plus 9V battery
€  2,00 9V battery clip
€ 51,00

Useful links

μc https://www.adafruit.com/product/2590
WiFi module https://www.adafruit.com/product/4264
Adafruit WiFiNINA library https://github.com/adafruit/WiFiNINA
Adafruit MQTT library https://github.com/adafruit/Adafruit_MQTT_Library