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)	SSTAMP_S3 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	0-40C
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