AHT20 with Teensy 4.1

Wiring for the AHT20 temperature + humidity on the Teensy 4.1 (MIMXRT1062DVJ6B, 3.3 V logic), chosen with the same pin rules BoardPilot uses: default buses first, and no pins that are used for flash, USB, the debugger or booting.

Wiring

Check before you power it on

• Supply: 3.3 V from the 3V pin.
• I2C uses the board’s default pins 18 (SDA) and 19 (SCL). Most modules include pull-up resistors; if the part is not found, check them and swap-test SDA/SCL.

Test code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin();  // SDA = 18, SCL = 19 (the board's default I2C pins)
  Wire.beginTransmission(0x38);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "AHT20 temperature + humidity found at 0x38" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Arduino board: teensy:avr:teensy41. Press the white program button once if the upload waits for the board.

Questions

Which Teensy 4.1 pins do I use for the AHT20?

VIN → 3V, GND → G, SCL → 19 (GPIO_AD_B1_00), SDA → 18 (GPIO_AD_B1_01).

Does the AHT20 work with the Teensy 4.1 at 3.3 V?

Yes: the AHT20 runs at 3.3-5 V and the Teensy 4.1 uses 3.3 V signals, so no level shifting is needed.

What is the I2C address of the AHT20?

0x38. An I2C scan (BoardPilot does it for you) shows which one your module uses.

Full Teensy 4.1 pinout · AHT20 temperature + humidity: all pins and data

The AHT20 on other boards

ESP32 DevKit Arduino Mega 2560 R3 Arduino Nano Arduino Uno R3 WeAct Black Pill STM32F411CE ESP32-C3-DevKitM-1 ESP32-S3-DevKitC-1 Nordic nRF52840 DK NUCLEO-F401RE Raspberry Pi Pico 2 Raspberry Pi Pico W Raspberry Pi Pico

Other parts on the Teensy 4.1

BME280 BMP280 DHT22 DHT11 HC-SR04 SSD1306 OLED MPU6050 DS18B20 WS2812B LED strip SG90 servo Relay module HC-SR501 PIR LCD 1602 I2C INA219 VL53L0X BH1750 MAX30102 RC522 RFID NEO-6M GPS Capacitive soil moisture sensor ADS1115 TM1637 28BYJ-48 stepper L298N Potentiometer Push button LED Joystick module SD card module