You will need to read all the information on this page to be able to use the Google Nest and British Gas Hive alternative known as ESPproMon. Available for Android and iOS smartphones and with an entry price starting below £30. You will need to use a valid email address when accessing our cloud-based server and we recommend using a Gmail address for this and for accessing the ESPproMon Community site. Please note that some of the details on this page refer to a standalone app but the ESPproMon project now runs as a much more flexible Blynk project.

ESPproMon will convert an “off the shelf” Energy meter into a state of the art iOT connected device. With the addition of a low cost microprocessor, known as an ESP8266, you can monitor electricity usage at your property, wherever you are in the world. Following 2 years of development, you will be able to get up and running with the minimum amount of effort.


  • Clear user interface with graphical display of electricity costs.
  • Thoroughly tested with the PeaceFair PZEM-004T hardware.
  • Powered by Blynk the leading digital dashboard provider.
  • Seamless linking to web-based API’s like Thingspeak and EmonCMS.
  • The ESP8266, manufactured by Espressif, is updated automatically via the internet as new features are added to the product.

So what is an ESP8266 and why would you want one? As of November 2017 Espressif has sold 100 million ESP8266 chips and it’s highlighted on the board to the right. As a standalone chip they are not very useful to the general public but companies like WeMos, Sparkfun, Adafruit and many others incorporated the chips into small development boards. These development boards are now available for less than $3 and the cost of developing WiFi embedded iOT projects has fallen dramatically.

With an ESP8266 development board and the ESPproMon firmware you are well on your way to a truly Smart Meter. You don’t have to be a computer geek, and we’ll guide you all the way, so let’s get started.

Order the firmware

Build or buy your own low cost Smart Energy Meter

ESPproMon V34 for interfacing a PZEM-004T and an ESP8266
ESP8266 on a WeMos D1 Mini Pro

Track your Energy usage in a different way!

We have all heard the horror stories of friends or family that have just received a huge electric bill right out of the blue. With an IOT connected Smart meter and our Smartphone app you will know from day to day how much you are spending on electricity. Not only will there be no more surprises but you should be able to reduce your electricity costs as you are able to monitor just how much each appliance costs to run.

Below is a very short video which demonstrates how the remote monitoring and control of your appliances works with the ESPproMon smartphone app, an ESP8266 and a PeaceFair Pzem-004T energy meter.

ESPproMon© Graph in landscape mode

To be able to flash the ESP8266 with the required bin file you will need a tool like runs via Python and can be installed on almost any machine. If you don’t already have Python just Google something like “install Python on Windows” or “install Python on Ubuntu” etc.

The GitHub for is available for download here. Do be aware there are several versions of esptool and one is used by the Arduino IDE. As some of you will not want to install the full IDE we recommend the Python version. uses a command line interface (CLI) rather than a graphical user interface (GUI) and the command instructions can be quite long. You should be able to simply cut and paste them from this page.

Once you have downloaded you need to download the bin file. We have two versions:

  1. Pzem connected to ESP8266 digital pins 12 and 13 (D6 and D7) for RX and TX with a variable resistor between Pzem and pin 12 (D6). Download this file and set the ota_url in WiFi Manager as
  2. Pzem connected directly to RX and TX pins on the ESP8266 with the 1K resistor modification on the Pzem. Download this file and set the ota_url in WiFi Manager as

Move the bin file to the directory where your copy of is located (so for example on Windows 8.1 it might be at C:\ESPTool4python\esptool-master). On most systems you will need Administrator / root access to be able to flash the bin file to your ESP. So with Windows 8.1 right click Command Prompt and click Run as Administrator. Then move to your esptool directory, for Windows it would be cd C:\ESPTool4python\esptool-master\

Make sure you don’t have the serial port open in any other applications like the Arduino IDE Serial Monitor, HyperTerminal, Termite or RealTerm etc. Then issue a command like the one below, changing COM4 to your specific Serial port.

WARNING: Ensure you set the correct parameters for your ESP as outlined hereFailure to do this correctly could destroy your ESP. The command below is for an ESP with 4MB of flash.

python -p COM4 write_flash -fm dio -fs 32m 0x0000 pzem.bin

If all goes well you should see the blue onboard LED flash on the ESP as it uploads the new firmware. Something like this will appear in the Command Prompt window: v1.2-dev
Running Cesanta flasher stub...
Flash params set to 0x0240
Writing 331776 @ 0x0... 331776 (100 %)
Wrote 331776 bytes at 0x0 in 28.6 seconds (92.9 kbit/s)...

Once you have flashed your ESP8266 with our firmware WiFi Manager will create an access point to connect the ESP8266 to your router. If you have previously set the WiFi credentials for your ESP8266 you will need to either clear them by flashing a sketch with the Arduino IDE parameter set to erase Sketch and WiFi settings or by temporarily turning off your router.

The access point is called PzemHouse and has a password of p4ssword. Connect to this with your smartphone or PC and enter the parameters shown on your screen. To obtain OTA updates you will need to manually reset the ESP8266 after you flash any bin files locally to the device. This is a requirement imposed by ESPRESSIF for all OTA updates.

Add your email address in the SETUP tab when the provisioning has been completed.

Full documentation for all the features in the app are available at the ESPproMon Community site.

PeaceFair PZEM Hardware

ESP8266 Firmware Enquiry

The ESPproMon project is now available for Android and iOS Smartphones. Once you have loaded the FREE Blynk app on your phone please complete the form below and we will send you details of the firmware you require for your ESP8266. You will be redirected to the ESPproMon Community site after you have sent your message. If you already have the firmware on your ESP8266 or simply wish to support the project please visit our contributions page. Once you have loaded the Blynk app on to your smartphone you will need to scan the image shown below.

ESPproMon V35 QR code image
Contact Us
Interface a PZEM-004T to an ESP8266 with ESPproMon
ESPproMon© Smart Meter and Control App

After installing the app on your phone please pop over to the ESPproMon community site for help and advice with all the features.

This is one of the most complex apps that you are ever likely to install on your smartphone and absolutely nobody will be able to guess the full installation process so registering on the Community site is imperative. You will need to work through the step by step guide on the site and do feel free to create a new topic if you have any questions or feedback regarding the app.

If you haven’t seen our “official” video to accompany the launch of the app it’s available here or on the community site in the Welcome section.