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Sensor Reference

This document lists every sensor used across all four Phaemos nodes, with interface details, libraries, measurement ranges, and datasheet links.

ESP32 Primary Node Sensors

Sensor Model Interface I2C Address Library (Arduino IDE) Measures Units Typical Range Datasheet
Barometric pressure / humidity / temperature BME280 I2C 0x76 Adafruit BME280 Temperature, humidity, pressure degC, %, hPa -40 to 85 degC / 0-100% RH / 300-1100 hPa [link to datasheet]
Accelerometer / gyroscope MPU6050 I2C 0x68 Adafruit MPU6050 or I2Cdev Acceleration (3-axis), angular rate (3-axis), temperature m/s^2, deg/s +/-2g to +/-16g (accel) / +/-250 to +/-2000 deg/s (gyro) [link to datasheet]
Current / power monitor INA219 I2C 0x40 Adafruit INA219 Bus voltage, shunt current, power V, mA, mW 0-26V bus / 0-3.2A (with 0.1 ohm shunt) [link to datasheet]
Microphone (sound level) MAX4466 Analog n/a n/a (analogRead) Sound pressure level (amplified) ADC counts (0-4095) Dependent on gain pot setting [link to datasheet]
Infrared thermometer MLX90614 I2C 0x5A Adafruit MLX90614 Object temperature, ambient temperature degC -70 to 380 degC (object) [link to datasheet]
Time-of-flight distance VL53L0X I2C 0x29 Adafruit VL53L0X Distance to object mm 30-1200 mm (up to 2000 mm in long range mode) [link to datasheet]
Gas / smoke sensor MQ-2 Analog + Digital n/a n/a (analogRead + digitalRead) LPG, propane, methane, smoke concentration ppm (calibrated) / raw ADC 300-10000 ppm (varies by gas) [link to datasheet]
Magnetic rotary encoder AS5600 I2C 0x36 AS5600 library (RobTillaart) Shaft angle, calculated RPM degrees (0-360), RPM 0-360 degrees continuous [link to datasheet]
Light-dependent resistor LDR (GL5528 or similar) Analog n/a n/a (analogRead) Ambient light level ADC counts (0-4095) ~10 lux to ~100 klux (resistance 1M to 10k ohm) [link to datasheet]
Contact temperature probe DS18B20 OneWire (GPIO4) n/a DallasTemperature + OneWire Temperature degC -55 to 125 degC [link to datasheet]
Soil / water moisture FC-28 Analog n/a n/a (analogRead) Moisture level, water presence ADC counts (0-4095), boolean Dry ~1023 / Wet ~300 (at 3.3V) [link to datasheet]

STM32 Black Pill Vibration Node Sensors

Sensor Model Interface I2C Address Library (STM32CubeIDE HAL) Measures Units Typical Range Datasheet
Accelerometer / gyroscope MPU6050 I2C1 (PB6/PB7) 0x68 Custom HAL_I2C driver or I2Cdev port Acceleration (3-axis), angular rate (3-axis); FFT processed to vib_magnitude and fft_peak_hz m/s^2, deg/s, Hz +/-2g to +/-16g / +/-250 to +/-2000 deg/s [link to datasheet]

Arduino Nano Secondary Node Sensors

Sensor Model Interface I2C Address Library (Arduino IDE) Measures Units Typical Range Datasheet
Barometric pressure / humidity / temperature BME280 I2C (A4/A5) 0x76 Adafruit BME280 Temperature, humidity, pressure degC, %, hPa -40 to 85 degC / 0-100% RH / 300-1100 hPa [link to datasheet]
Light-dependent resistor LDR (GL5528 or similar) Analog (A0) n/a n/a (analogRead) Ambient light level ADC counts (0-1023 at 10-bit) ~10 lux to ~100 klux [link to datasheet]
Soil / water moisture FC-28 Analog (A1) n/a n/a (analogRead) Moisture level ADC counts (0-1023 at 10-bit) Dry ~1023 / Wet ~300 [link to datasheet]

Raspberry Pi Pico 2W Ambient Node Sensors

Sensor Model Interface I2C Address Library (MicroPython) Measures Units Typical Range Datasheet
Barometric pressure / humidity / temperature BME280 I2C0 (GP4/GP5) 0x76 micropython-bme280 (unofficial) Temperature, humidity, pressure degC, %, hPa -40 to 85 degC / 0-100% RH / 300-1100 hPa [link to datasheet]
Light-dependent resistor LDR (GL5528 or similar) ADC (GP26/ADC0) n/a machine.ADC Ambient light level ADC counts (0-65535 at 16-bit) ~10 lux to ~100 klux [link to datasheet]
OLED display SSD1306 I2C0 (GP4/GP5) 0x3C ssd1306 MicroPython driver n/a (output device, not a sensor) n/a 128x64 pixel display [link to datasheet]

I2C Bus Address Reference and Conflict Resolution

The following I2C addresses are used across the Phaemos nodes:

Address Device Node
0x29 VL53L0X ESP32
0x36 AS5600 ESP32
0x3C SSD1306 OLED ESP32, Pico 2W
0x40 INA219 ESP32
0x5A MLX90614 ESP32
0x68 MPU6050 ESP32, STM32
0x76 BME280 ESP32, Nano, Pico 2W

Handling address conflicts on the same bus:

Each node has its own I2C bus, so there is no conflict between nodes. However, within the ESP32 node, if a second BME280 were ever needed (for example to measure temperature at two different points), the address can be changed:

  • BME280: pull the SDO pin HIGH (to 3.3V) to change address from 0x76 to 0x77. You can run one BME280 at 0x76 and one at 0x77 on the same bus.
  • MPU6050: pull the AD0 pin HIGH to change address from 0x68 to 0x69.
  • INA219: the A0 and A1 address pins can be tied to GND or VCC to select one of four addresses (0x40, 0x41, 0x44, 0x45), allowing up to four INA219s on one bus.
  • VL53L0X: the address is fixed at 0x29 in hardware but can be reassigned in firmware at boot time using the XSHUT pin. Bring each VL53L0X online one at a time via XSHUT and assign a unique address before releasing the next one.
  • AS5600 and MLX90614 have fixed addresses and only one of each can be used per I2C bus.