This is an iot based smart energy meter that I made it can monitor power, current, watt hour and unit energy consumed by the device
You can see the working video here

Supplies

Nodemcu, acs712

Step 1: Wiring

You can see the working of the project here

First of Al you have to make a extension board, and we need to connect Acs712 sensor to it so that we can measure current

First connect gnd, vcc of the sensor to nodemcu, then connect sensor output to the A0 of nodemcu

Detailed diagram will be provided

Step 2: Coding

Upload code to nodemcu, you have to change three things in the code

1 blynk authentication key

2 WiFi ssid

3 WiFi password.

Change this three things and upload the code into nodemcu

Step 3: Blynk App Setup

It is a very symbol process. First you have to download Blynk from play store

From the top right corner of it you can see a scanner
option click on it and scan the qr code given below

Step 4:

After that you will get something like this

Step 5:

Then sear for blynk authentication key and copy it and paste it in your code

It can be find by clicking the hexagonsymbol on the top right corner

Step 6:

Now you will be directed to a page like this which contains the option to copy the code email it

Congratulations you have successfully created a energy monitoring system

Now you can monitor power consumption of the device connected to it via your android phone from anywhere in the world