M5Stack Voltage and Amperage Meter with M5StampS3

This VA Meter is a high-precision, programmable power meter designed for accurate voltage and current measurements. Based on the M5StampS3 control module, it supports WiFi connectivity. It includes two serially connected INA226 circuits for precise current detection, with resolutions of 2.5uA and 250uA, and a measurement range of 0-5A and 5-24V (1-24V in isolation mode). Power can be supplied via USB-C or Base terminal input, with built-in power and signal isolation. The device also supports OTA firmware upgrades, and USB MSC/OTG functionality, and offers a free online data API for easy IoT integration. This meter is great for engineering projects, industrial automation, equipment monitoring, and smart grids. If you need precise voltage and amp measurements, this is the meter for you! Features

* High precision current detection (2.5uA/250uA precision switching)

* Wide voltage input (5-24V)

* Cloud (EZData) real-time data display

* PD input (internal does not contain PD decoy)

* Multiple power supply modes (PD INPUT/StampS3/External terminal)

* Power is isolated from signal

* USB MSC/OTG function

* Open-source hardware and software

* OTA Upgrade

Specifications

Power detection chip INA226

SoC ESP32S3FN8@Xtensa® 32-bit LX7 dual-core processor up to 240 MHz

Flash 8MB Flash

PSRAM N/A

Wi-Fi IEEE 802.11 b/g/n (2.4 GHz Wi-Fi)

Screen 1.3"@ 240 x 240 Pixel

Screen Driver ST7789

PD Input/Output Power 5-24V@0-5A

Current detection resolution 2.5uA/250uA

Current sampling error Small current (1-100mA) sampling error: 1.01%

Large current (100mA-5A) Sampling error: 0.94%

UA-level current sampling error: 0.69%

Power Consumption (factory firmware) SSTAMPS3 USB power supply: DC5V/123.5mA

PD INPUT power supply: DC5V/118mA, DC12V/66.8mA DC24V/26mA

PD OUTPUT capability DC24V/3A 68℃

DC24V/5A 92℃

USER interaction Rotary encoder switch, reset button, boot button and board

INA226 Communication Address Two detection chips INA226:0x40/0x41

Relay DC 5-24V @5A

Operating Temperature 0-40°C

Product Size VAMeter 36 x 36 x 14.7mm

VAMeter 36 x 36 x 20.3mm

Rail Fastening 51.5 x 48 x 5.5mm

Package Size 150 x 93 x 30mm

Product Weight VAMeter: 17.7g VAMeter Base: 25.8g

Rail Fastening 4g

Package Weight 68.1g

Resources

* Product Wiki

* Tutorial

* Schematic

* Base Schematic

* Base PCB

Package Contents

* 1x VA Meter

* 1x VA Meter Base

* 2x 3.81-2P terminal

* 4x Hanger (Small)