MAX30100

Connects over

I²C

Address

0x57

Made by

Maxim Integrated

Datasheet

datasheets.maximintegrated.com

Use it

hardware {
    device max30100: MAX30100
}

every 1s {
    let value: int = max30100.red()
    log("max30100", "red={value}")
}

On its own, the declaration puts the MAX30100 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 max30100: MAX30100 on i2c0 at 0x57 with i2c i2c0(sda: 21, scl: 22).

Methods

• max30100.red() -> int

  Red LED raw value

• max30100.ir() -> int

  IR LED raw value

• max30100.temperature() -> float

  Die temperature °C

• max30100.is_finger_present() -> int

  1 if finger detected

Wiring

Specifications

Voltage

1.8V (digital) + 3.3V (LEDs) — most breakouts handle this internally

Current

600 μA – 4 mA depending on LED brightness

Modes

Heart-rate + SpO₂

Leds

Red (660 nm) + IR (880 nm)

Tips

• Algorithm for SpO₂ / BPM is non-trivial — usually computed off-chip from raw samples.
• Skin contact matters: finger too loose = noisy, too tight = no perfusion.
• Many cheap modules ship with a wrong-value pull-up resistor — fix is documented online.

Alternatives worth knowing:

• MAX30102: Newer chip, same role, lower noise, smaller footprint.