Introduction: DIY Wireless Power Meter | 100VDC 100A

About: Hi my name is Steve and i'm a Creative and I got Technical skills i can build anything just stick to my account . I'm a YouTuber so you also can see my all videos here

Hey! everyone, My name is Steve

Today I’m gonna show how I build this Power Meter Using ESP8266 & INA226 Current Sensor

The Screen seems to fluctuate it’s just due to the camera in real it’s normal

I’ve built the Codes with ESPHome

These can measure current 1mA to 100Amp and Voltage up to 100VDC, and it’s very precise
And yes it can also measure negative current

And I also have added DHT11 So it can measure Temperature & Humidity

It can also be integrated with your Home Assistant and you can see it wirelessly I’ll mostly use this for capacity testing Lifepo4 Battery

This is the First Version I’ve made there are so many things to improve

Click Here to See The Video

Let's Start

Step 1: Features

Input Power

  • 5V DC


  • 0-100VDC
  • 0-100A

Built-in Features

  • 0.96" Oled
  • OTA Update
  • Temperature & Humidity Read
  • Wireless
  • Extra Ports for Future Expandability

Step 2: Precesion Samples

I used my lab bench power supply to test it and it seems very accurate there are very few errors and you can always calibrate it

Step 3: Thing I've Used



Step 4: Making PCB

I generally try to make everything professionally so I use JLCPCB to make my dream come true.

Talking about JLCPCB it's the world largest PCB manufacturing company and provide very fantastic results

You can see the above image as a reference

Now, JLCPCB are offering

  • $2 for 2Layer, 5pcs
  • $5 for 4Layer, 5pcs

Gerber & Schmitics - Download

Step 5: Why ESPHome

I use Home Assistant to run ESPHOME it's very easy to work with and gives wireless capabilities

It uses YAML and the coding is very user friendly

Step 6: SMD

I generally use SMD Resistance and Capacitors Book it's easy to work with everything is well sorted

Step 7: After Gathering All the Parts

Started Soldering 4 Resistance and 1 Capacitor.

Then soldered the female headers yes it gives height but gives easy replaceability

And soldered DHT11

Note - Please see the images for better understanding

Step 8: Assembly

Started with mounting the Old then INA226 and then ESP8266 Module

Note - Please see the images for better understanding

Step 9: Removing the OLD Shunt Resistance

It's very necessary to remove the On-Board resistance later we are gonna use a 100A Shunt

Note - Please see the images for better understanding

Step 10: Unnecessary Stuff :p

Pealing off the protective film is fun :p

Step 11: Finished PCB

All set for Programming

Step 12: Programming

After Plugging the USB into the computer I use Tasmotizer to Flash .bin files

Download Code

Step 13: First Boot Up

You'll be welcomed with cute little 0.96" Oled showing data

Wait for 30 Second and you'll see Current Temperature & Humidity

Step 14: Wiring Diagram

Note - Please see the images for better understanding

Step 15: Preparing Shunt

Note - Please see the images for better understanding

Step 16: Finishing Up

You can see everything is working and precise

That's all for today guys!
Click Here to See The Video

You Just Made It Thank you for visiting my Instructables Stay tuned for the next Projects