Building an NodeMCU ESP8266 Internet Connected Four-Relay Switch - DZone IoT | #Arduino #Coding #Maker #MakerED #MakerSpaces  | 21st Century Learning and Teaching | Scoop.it
From dzone.com - September 27, 2018 11:03 AM

In our case, we use NODEMCU ESP8266, but you can use any other type of ESP8266 with all pins exposed. In our program, we connect D0, D1, D2, and D3 in a circuit, which controls the relays. The relays are using 5V. ESP8266 is using 3.3V. To connect the 3.3V ESP8266 to the 5V relay module, we use one NPN transistor 2N2222. 

 

Learn more / En savoir plus / Mehr erfahren:

 

https://www.scoop.it/t/21st-century-learning-and-teaching/?&tag=NodeMCU

 

https://www.scoop.it/t/21st-century-learning-and-teaching/?&tag=ESP8266+WiFi+Module

 

https://www.scoop.it/t/21st-century-learning-and-teaching/?&tag=ARDUINO