How it works :
I make a customized circuit board to control 4 relays by esp8266 NodeMcu This circuit runs on DC 12 volt 1 amp power. when power on nodemcu connect to you router via WiFi & also connect with Blynk server
Your smart phone send command to Blynk server & Blynk cloud server send command to nodemcu . The D0,D2,D3,D4 pin of nodemcu became high or low then relay turn on or off connected Ac appliances.
Step 1: You Need to Make
Esp 8266 NodeMcu Lolin
12 volt 1 amp power adapter
IC7805 - 1 pcs
Transistor Bc 548b - 4 pcs
Resistors 10K - 4 pcs & 1K - 5pcs
Diode IN4007 - 4pcs
Relay 12V - 4pcs
Led red - 1pcs & green - 4 pcs
Capacitor 470uf/25V - 1pcs
Female Header connector
Terminal block - 4pcs
Step 2: Making
we are using professional quality PCB so making is very easy
just put all parts to PCB (All parts name printed on PCB) Solder all components & cut extra lid of parts.
Step 3: Software Part
Download & install Blynk app in your android phone
sing-up to Blynk using an email id
Then create a new project & select board Nodemcu ( you can see Video)
After creating new project Blynk will send a Authentication code in your email Id copy this code.
Now go to your pc. You need Arduino Ide to program node mcu If you have not use Nodemcu before it ,then you have to download Esp 8266 nodemcu board from Board manager of arduino ide (Here is a guide for add Nodemcu to arduino ide)
Then Download Blynk library from here
Now open Arduino Ide go to Examples>Blynk >Boards_wifi>NodeMcu.
Just put your Auth Code (witch you received in email) ,your Router name & password
Upload code to Nodemcu.
Step 4: Setup Blynk App & Connect With Ac Appliances
Now open Blynk app on your phone
Add 4 buttons using pin D0,D2,D3,D4
Those pins are controlling Relay in our circuit board
congratulation have you complete software part .
before connect AC please check all connection working properly .The red led will indicate power is ok &
4 green Leds will glow when you tap button on Blynk app.
Now plug power of 12v adapter and you can control lights or fan using Blynk app button
Now connect Ac appliances with circuit board .follow connection diagram