MAX30102

Connects over

I²C

Address

0x57

Made by

Maxim Integrated

Datasheet

datasheets.maximintegrated.com

Use it

hardware {
    device max30102: MAX30102
}

every 1s {
    let value: int = max30102.red()
    log("max30102", "red={value}")
}

On its own, the declaration puts the MAX30102 on the first I²C bus (SDA 21, SCL 22 on the ESP32) at 0x57. To choose the pins or the address, declare the bus and attach the device: device max30102: MAX30102 on i2c0 at 0x57 with i2c i2c0(sda: 21, scl: 22).

Methods

• max30102.red() -> int

  Red LED raw value

• max30102.ir() -> int

  IR LED raw value

• max30102.temperature() -> float

  Die temperature °C

• max30102.is_finger_present() -> int

  1 if finger detected

Wiring

Specifications

Voltage

1.8V digital + 3.3V LED — breakout regulators handle both from a single 3.3V/5V input

Current

600 μA – 4 mA

Modes

Heart-rate + SpO₂

Leds

Red (660 nm) + IR (880 nm)

Tips

• Designed for wearables — lower noise than MAX30100.
• Place finger over the sensor with steady pressure; movement is the #1 source of bad readings.
• Use the FIFO + interrupt rather than polling — keeps timing tight without main-loop work.

Alternatives worth knowing:

• MAX30100: Older, slightly higher noise, still common in DIY kits.