DHT Module

Read temperature (Celsius) and relative humidity (%) from DHT11 and DHT22 sensors.

Firmware setup

; platformio.ini
build_flags = -DCONDUYT_MODULE_DHT

#include <Conduyt.h>

ConduytSerial transport(Serial, 115200);
ConduytDevice device("WeatherStation", "1.0.0", transport);

void setup() {
  Serial.begin(115200);
  device.addModule(new ConduytModuleDHT());
  device.begin();
}

void loop() {
  device.poll();
}

Wiring

DHT22 (bare 4-pin sensor)

DHT22 (front view)
┌─────────┐
│  ┌───┐  │
│  │   │  │
│  └───┘  │
└─┬─┬─┬─┬┘
  1 2 3 4

1=VCC  2=DATA  3=NC  4=GND

Required: 10k ohm pull-up resistor between VCC and DATA.

3-pin breakout boards

Breakout boards have the pull-up resistor built in. Just connect VCC, DATA, GND — no extra resistor needed. Check your breakout's labeling (often marked S/+/- or DATA/VCC/GND).

Host usage

JavaScript

// dht.mjs
import { ConduytDevice } from 'conduyt-js'
import { SerialTransport } from 'conduyt-js/transports/serial'
import { DHT } from 'conduyt-js/modules/dht'

const device = await ConduytDevice.connect(
  new SerialTransport({ path: '<YOUR_PORT>' })
)

const dht = new DHT(device, 0)

// Initialize: pin 4, sensor type 22 (use 11 for DHT11)
await dht.begin(4, 22)

// Wait for sensor to stabilize
await new Promise(r => setTimeout(r, 2000))

// Read temperature and humidity
const { temperature, humidity } = await dht.read()
console.log(`Temperature: ${temperature.toFixed(1)} C`)
console.log(`Humidity: ${humidity.toFixed(1)} %`)

await device.disconnect()

Python

# dht.py
import asyncio
from conduyt import ConduytDevice
from conduyt.transports.serial import SerialTransport
from conduyt.modules import ConduytDHT


async def main():
    device = ConduytDevice(SerialTransport('<YOUR_PORT>'))
    await device.connect()

    dht = ConduytDHT(device, module_id=0)

    # pin=4, sensor_type=22 for DHT22 (or 11 for DHT11)
    await dht.begin(pin=4, sensor_type=22)

    # Wait for sensor to stabilize after power-on
    await asyncio.sleep(2)

    reading = await dht.read()
    print(f"Temperature: {reading.temperature:.1f} C")
    print(f"Humidity: {reading.humidity:.1f} %")

    await device.disconnect()


asyncio.run(main())

Command reference

Read response format

temperature (4 bytes, float32, little-endian)
humidity    (4 bytes, float32, little-endian)

DHT11 vs DHT22

Troubleshooting

• Returns 0.0 / 0.0: the sensor hasn't stabilized yet. Add a 2-second delay after begin() before the first read().
• Returns NaN: check wiring. The pull-up resistor is required for bare sensors. Also verify VCC matches your board's voltage (3.3V for ESP32, 5V for Uno).
• Stale readings: DHT sensors have a minimum sampling interval. Reading faster than 2 seconds (DHT22) or 1 second (DHT11) returns cached data.