Light, distance and motion

AS5600 magnetic encoder with ESP32

Unlike a rotary encoder, the AS5600 knows its absolute angle the moment it powers up, with nothing touching the shaft. A small magnet on the shaft end sits above the chip, and it reports a full turn in 4096 steps, about 0.1° each. That makes it good for knobs that must survive a reboot, or for a wind vane.

The magnet has to be diametric, magnetised across its diameter. An ordinary axial disc will not work, and most modules ship with the right one, so keep it. Centre it over the chip. Distance matters too, so check the datasheet for your magnet. The status register tells you if the setup is right: it reports magnet detected, too strong and too weak. The example prints that, and you should look at it before you trust any angle. Shafts made of steel distort the field, so non-magnetic mounting helps.

Tie the DIR pin to a defined level: it sets the direction of rotation, with low as clockwise in the common library, and it should not float. The address is fixed at 0x36, so only one fits on a bus. The AS5600L is a different part at 0x40 that can be changed. The library author reports that pull-ups are mandatory, and that an ESP32 can block for up to a second if the sensor connection fails. So avoid polling it in a path that the display depends on. Some modules also have a resistor on PGO that disables the OUT pin.

#include <Wire.h>

const int SDA_PIN = 8, SCL_PIN = 9;
const uint8_t ADDR = 0x36;

uint16_t read(uint8_t reg, uint8_t n) {
  Wire.beginTransmission(ADDR);
  Wire.write(reg);
  Wire.endTransmission();
  Wire.requestFrom(ADDR, n);
  uint16_t v = 0;
  while (n--) v = (v << 8) | Wire.read();
  return v;
}

void setup() {
  Serial.begin(115200);
  Wire.begin(SDA_PIN, SCL_PIN);
}

void loop() {
  uint8_t status = read(0x0B, 1);
  uint16_t raw = read(0x0C, 2) & 0x0FFF;
  Serial.printf("%.1f deg  magnet %s%s%s\n", raw * 360.0 / 4096,
                status & 0x20 ? "found" : "MISSING",
                status & 0x10 ? ", too weak" : "", status & 0x08 ? ", too strong" : "");
  delay(200);
}

Use this information at your own risk. It is for general guidance only: the example code compiles, but it has not been tested on every part, and modules differ between sellers. Check the manufacturer's data before you build. Product names belong to their owners, and LCD Ultra Pro is not affiliated with them. See our Terms.