Ingredient
DHT22 temperature-humidity sensor
Also known as: AM2302, DHT22
Single-wire digital temperature-and-humidity sensor — the cheapest commodity 2-in-1 environmental sensor in the hobbyist pantry. ~$3–5; reads on a single GPIO pin via a custom 1-wire protocol; 3.3V or 5V; ±0.5°C, ±2% RH. Slower and less accurate than BME280 and lacks pressure, but the lowest barrier to entry for a teaching project or a low-cost greenhouse logger. Reads at 0.5 Hz max.
Inputs / outputs
- Power: 3.3V or 5V, ~1.5 mA active
- Interface: custom 1-wire protocol (not Maxim 1-Wire — vendor-specific)
- Range: −40 to +80°C, 0–100% RH
- Accuracy: ±0.5°C, ±2% RH
- Sample rate: ≤0.5 Hz (sensor needs 2 seconds between reads)
Solves / unlocks
- First-project greenhouse logging
- Brood-box and cold-frame monitoring
- Indoor seedling-tray climate
- Pairs with cheap relays for fan/heater on/off control via threshold
Constraints
- Slow — 0.5 Hz max read rate.
- Single-wire protocol is timing-sensitive; software-serial implementations sometimes fail on multitasking systems.
- Plastic enclosure absorbs water — recovery from condensation is slow.
Source
- Datasheet: https://www.adafruit.com/product/385
- Library: https://github.com/adafruit/DHT-sensor-library
See also
Auto-generated from this entry’s typed relations: frontmatter, grouped by relation type so the editorial signal isn’t flattened.
- Parallels: [[bme280-environmental-sensor]]
- Member of: [[ingredient]]
- Combines with: [[arduino-uno]] · [[esp32]]
What links here, and how
Inbound connections from across the wiki, grouped by lens and by relationship. These appear automatically — every entity page declares what it links to, and that data populates here on the targets.
Practical
combines with
- Arduino Uno single-wire library; greenhouse environmental logging
- BME280 environmental sensor BME280 is the better successor to DHT22 — faster, more accurate, adds pressure
contains
- Farm-tech toolkit sensor / cheap temp+humidity, first-project pairing
3 inbound links · 4 outbound