Description The M5Stack Ammeter Unit (ADS1115) is a compact current meter for real-time current monitoring in embedded, automation, and prototyping projects. Built around the 16-bit ADS1115 analog-to-digital converter, it communicates over I2C at the default address 0x48 and measures current up to ±4A. The M5Stack Ammeter Unit (ADS1115) includes an isolated DC-DC power supply and CA-IS3020S I2C isolation to help keep bus noise and surge interference away from sensitive local circuits. It is factory calibrated with 1% full-scale accuracy ±1 digit, 0.3mA resolution, and an internal 4A fuse for overcurrent protection. Note Calibration parameters: EEPROM (0x51) stores factory calibration data. Do not write to the EEPROM; otherwise the calibration data may be overwritten and measurements can become inaccurate. Features ±4A current measurement range 16-bit ADS1115 ADC conversion 1% full-scale accuracy ±1 digit with 0.3mA resolution Built-in 4A fuse and overcurrent protection LED power indicator Factory calibration data stored in EEPROM CA-IS3020S I2C isolator for improved anti-interference performance Isolated DC-DC power supply Arduino, UIFlow, and Home Assistant development support 2 x LEGO compatible holes for mechanical mounting Specifications Measurement Range ±4A ADC 16-bit ADS1115 Communication Interface I2C, default address 0x48 Isolation CA-IS3020S I2C isolator; isolated DC-DC power supply Accuracy 1% full scale ±1 digit Resolution 0.3mA Protection Internal 4A fuse and overcurrent protection Product Size 56.0 x 24.0 x 8.0mm Product Weight 8.4g Package Size 138.0 x 93.0 x 9.0mm Gross Weight 16.7g Applications Real-time current measurement for embedded devices Power monitoring in IoT and automation projects Arduino, UIFlow, and Home Assistant sensor projects Bench testing and overcurrent-aware prototyping Product List 1 x Unit AMeter 1 x HY2.0-4P Grove cable (20cm) 1 x VH3.96-4P Terminal Other Content PinMap HY2.0-4P Wire Function Black GND Red 5V Yellow SDA White SCL Resources Product documentation CA-IS3020S datasheet ADS1115 datasheet Arduino examples UIFlow documentation Home Assistant integration EasyLoader example FAQ What current range does the M5Stack Ammeter Unit (ADS1115) support? The M5Stack Ammeter Unit (ADS1115) supports a ±4A measurement range and includes an internal 4A fuse for protection. Which interface does the Ammeter Unit use? The unit communicates over I2C with the default address 0x48 and uses the ADS1115 16-bit ADC. Does the module need recalibration? Recalibration is normally not required because factory calibration data is stored in EEPROM. Avoid writing to EEPROM address 0x51.
