| Metric | HTU21D | Si72021 | DHT22 | DHT22 vs HTU21D Difference | BME280 |
|---|---|---|---|---|---|
| Cost in 1k off | £2.15 | £4.57 (July16) | 3.2 times cheaper (£3.15 less!) | £3.07 | |
| Vcc | 1.9V - 3.6V | 3.3-6V | 1.71 V - 3.6V | ||
| Humidity accuracy | ±2% RH | ±2%RH | n/a | ±3%RH | |
| Humidity Range | 0-100% RH | 0-100% RH | n/a | 0-100% RH | |
| Temperature accuracy | ±0.4°C | ±0.5°C | 40% more accurate | ±0.5 - ±1.0 | |
| Temperature Range | -40°C +125°C | -40°C +80°C | 56% more accurate | -40°C +80°C | |
| Sleep Current | 0 | 0.06uA | 15uA | 750 times less power | 0.1uA - 0.3uA |
| Measurement Current | 0. 0.09 mA | 0.5mA | 11 times less power | 0.714mA - 0.350mA | |
| Measurement time | 0.01s | 0.01s - 0.0026s | 2s | 200 times faster | 0.013s |
| Energy consumed per sample | 2.97uJ | 3300uJ | 2000 times less power | ||
| Time sampling per day* | 2800s | ||||
| Time sleeping per day* | 83600s | ||||
| Energy consumed per day* | 8700mJ [2] | 1115 times less energy per day! |
energy consumed (joule, J) = potential difference (volt, V) × charge (coulomb, C)
charge (coulomb, C) = current (ampere, A) × time (second, s)
energy consumed (joule, J) = potential difference (volt, V) × current (ampere, A) × time (second, s)
Energy consumed per day = energy consumed per sample + energy consumed while sleeping.
- HTU21D: (1400 * 0.0015mJ) + (3.3V * 0.00002mA * 86386 ) = 2.1mJ + 5.7mJ = 7.8mJ [1]
- DHT22: (1400 * 3.3mJ) + (3.3V * 0.015mA * 83600) = 4.6mJ + 4.1J = 8.7J = 8700mJ [2]
*Assuming 1 sample per min and sleeping in between samples: 1400 samples per day