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4-pin Module · DHT11
ActiveTemperature + Humidity Sensor
DHT11
Aosong · 4-pin Module · Temperature + Humidity Sensor
Price on Request
Get a competitive quote within 24 hours. Volume discounts available. Shenzhen stock ships in 1-2 business days.
Overview
The DHT11 is the entry point of Aosong's digital humidity and temperature family and remains one of the highest-volume low-cost environmental sensors ever shipped. A resistive humidity element and an NTC thermistor are connected to an internal high-performance 8-bit microcontroller, which reads both channels, applies the calibration coefficients stored as program data in OTP memory and outputs a pre-formatted digital word. Every device is calibrated in a precision humidity chamber, so parts are fully interchangeable with no per-unit trimming in firmware.
The specification is modest but well documented. Humidity accuracy is ±5 percent RH across 0 °C to 50 °C and ±4 percent RH at 25 °C, with 1 percent RH (8-bit) resolution, ±1 percent RH repeatability, ±1 percent RH hysteresis and ±1 percent RH per year long-term stability. The usable humidity window is temperature dependent: 30 to 90 percent RH at 0 °C, 20 to 90 percent RH at 25 °C and 20 to 80 percent RH at 50 °C. Temperature accuracy is ±2 °C maximum with ±1 °C typical over a 0 °C to 50 °C range at 1 °C resolution. Response time is 6 s to 15 s (63 percent, 1 m/s air) for humidity and 6 s to 30 s for temperature, which is why the DHT11 belongs in slow ambient monitoring rather than fast process control.
On the bus side the DHT11 uses a single bidirectional wire. The host pulls the line low for more than 18 ms, releases it, and the sensor answers with an 80 µs low pulse followed by an 80 µs high pulse before clocking out 40 bits, MSB first: humidity integer, humidity decimal (currently always zero), temperature integer, temperature decimal (currently zero) and a checksum equal to the low 8 bits of the sum of the four data bytes. A full exchange takes about 4 ms. Supply is 3 V to 5.5 V DC per the technical data sheet (3.3 V to 5.5 V in the English product manual), standby current is about 60 µA and measuring current is around 0.3 mA. Aosong recommends a 5 kΩ pull-up for runs shorter than 20 m, a 100 nF decoupling capacitor at the sensor, waiting 1 s after power-up before the first command and sampling no faster than once every 2 s.
Because the part costs pennies, counterfeit economics differ from the DHT22: the usual problem is not a fake DHT11 but a DHT11 remarked and sold as a DHT22. Still, verify marking, leads and lot traceability on every lot, and bench-check that the temperature channel tracks a reference within ±2 °C. Our Shenzhen stock includes the bare 4-pin sensor and the 3-pin module version with on-board pull-up; MOQ is 500 pcs for the bare sensor or 200 pcs for modules, shipping in 1-3 days.
Key Features
- 20 to 90 percent RH at ±5 percent RH and 0 to 50 °C at ±2 °C
- Calibrated 8-bit digital output on a single bidirectional data wire
- Fully interchangeable — OTP calibration coefficients per device
- 3 V to 5.5 V supply with about 60 µA standby current
- 4-pin outline drop-in compatible with the DHT22
Typical Applications
- Consumer humidistats, dehumidifiers and low-cost HVAC panels
- Classroom kits, STEM boxes and Arduino or ESP32 starter projects
- Warehouse, museum and storage-cabinet environment logging
- Appliance control boards needing a coarse comfort reading
- Agricultural greenhouse monitors at low unit cost
Specifications
- Temperature Range
- 0 to 50 °C
- Temperature Accuracy
- ±2 (typ ±1) °C
- Humidity Range
- 20 to 90 %RH
- Humidity Accuracy
- ±5 (±4 at 25 °C) %RH
- Resolution
- 1 °C / 1 %RH (8-bit)
- Interface
- Single-Bus Digital Serial
- Supply Voltage
- 3.3 to 5.5 V
- Standby Current
- 60 µA
- Pins
- 4
- RoHS
- Compliant
Procurement Tips
If your design will ever be re-rated for tighter accuracy or sub-zero operation, put a DHT22 on the same footprint from the start — the 4-pin outline and driver are shared, so the upgrade costs a fraction of a dollar instead of a board respin.
Frequently Asked Questions
What exactly is different between the DHT11 and the DHT22?
Range, resolution and accuracy. DHT11: 0-50 °C at ±2 °C and 20-90 percent RH at ±5 percent RH, 1-unit (8-bit) resolution. DHT22: -40 to 80 °C at ±0.5 °C and 0-100 percent RH at ±2 percent RH, 0.1-unit (16-bit) resolution. The single-bus protocol, pinout and 4-pin package are the same, so swapping is normally a firmware scaling change. The DHT11 start pulse is 18 ms minimum and the DHT22 accepts 1 ms, so keep the longer pulse when sharing one driver.
Can I run the DHT11 from 3.3 V?
Yes. The technical data sheet specifies 3 V to 5.5 V and the English product manual 3.3 V to 5.5 V. Two cautions: at 3.3 V keep the cable under 1 m or the drop across the line will starve the internal regulator and bias the reading, and make sure the DATA pull-up is tied to the same 3.3 V rail as VDD so the logic high level is correct.
Why does my DHT11 return 0, 0 or fail the checksum?
The usual causes are a start pulse shorter than 18 ms, a missing or wrong-value pull-up, interrupt latency from other code, or polling faster than the 2 s minimum. The sensor only converts when triggered, so a second read within the sampling window returns the previous result. Disable interrupts during the 40-bit exchange, use a 4.7 kΩ to 5.1 kΩ pull-up and validate the checksum byte before accepting data.
Is the DHT11 accurate enough for HVAC or dehumidifier control?
For comfort-band control, yes — a ±5 percent RH window is acceptable where the setpoint has a 5 percent to 10 percent hysteresis band. For dehumidification with tight energy targets, for anything audited or logged, or where condensation is possible, move up to a DHT22 (±2 percent RH) or an I2C sensor such as the Sensirion SHT31 or Bosch BME280 (±3 percent RH, faster response).
How fast can I sample it, and why is the response so slow?
The datasheet recommends a sampling interval greater than 2 s, and Aosong notes that repeated reads closer than about 5 s can return stale data. The physical reason is the resistive humidity element and the encapsulated NTC: 63 percent response takes 6 s to 15 s in 1 m/s air. Do not expect the DHT11 to follow a step change in under a minute; if your application needs a 1 s response, use a capacitive sensor such as the BME280.
How do I check for counterfeit or remarked units?
Verify laser-etched marking that will not scrape off, matte-tin leads, correct package mass and a legible lot code. Then do a two-point functional test: compare against a reference hygrometer at room conditions and confirm the temperature channel tracks within ±2 °C, and cool the sensor toward 0 °C where a clone or a DHT11 die sold as a DHT22 will misbehave. Because the DHT11 die is commonly remarked as a DHT22, checking decimal-byte resolution is the single most effective screen.
What is the MOQ and lead time?
MOQ 500 pcs for the bare 4-pin DHT11 sensor, 200 pcs for the module version with on-board pull-up, or 5,000 pcs for OEM bagged lots with negotiated pricing. Shenzhen stock ships in 1-3 business days; Aosong channel replenishment is normally 2-4 weeks.
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