ESP8266/32 (Home Assistant Switch) connected to PCF8574 controlling 8 relays

Home Assistant Switch for 8 Relays

• Code can compile on ESP8266/32
• PCF8574 can be used to extend the GPIO of ESP8266/32
• 8 ports of PCF8574 is connected to 8 Relay module

Libraries Needed

platformio.ini is included, use PlatformIO and it will take care of installing the following libraries.

Library	Link
MQTT	https://github.com/256dpi/arduino-mqtt
ArduinoJson v6	https://github.com/bblanchon/ArduinoJson
WiFiManager Develop	https://github.com/tzapu/WiFiManager/archive/development.zip
PCF8574 Library	https://github.com/xreef/PCF8574_library
Arduino WebSockets	https://github.com/Links2004/arduinoWebSockets
UpdateUploadServer (ESP8266)	https://github.com/debsahu/DDUpdateUploadServer

Hardware

Items

1. ESP8266 (aliexpress) / ESP32 (aliexpress)
2. 3.3V to 5V converter (aliexpress)
3. PCF8574AP (aliexpress)
4. 8-port relay (aliexpress)
5. Plastic Box (amazon)
6. AC plug socket (aliexpress)
7. 3-pin AC cable (aliexpress)
8. 2 sockets (Home Depot)

Instructions

• Break the tab on the sides with brass screws
• Connect each of the brass screws to Normally Open (N/O) on relay

• Use PCF8574AP (exact version used here)
• Use 3.3V to 5V level shifters for ESP8266 I2C data
• Set A0, A1, A2 to GND so I2C address is 0x20
• Use 5V as VCC on PCF8574AP
• Use a good 110V AC to 5V DC device like a phone charger