Sonoff Sensor Si7021

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Sonoff TH sensor Si7021 02.jpg

Sonoff Si7021 Temperature and Humidity Sensor is a digital temperature and humidity sensor with a calibrated digital signal output. It adopts dedicated digital module acquisition technology and temperature&humidity sensing technology to ensure that the sensor has a very high reliability and excellent long-term stability. The sensor includes an integrated single-chip temperature and humidity sensor chip, which connects to a high-performance 8-bit MCU. The Si7021 sensor has advantages such as excellent quality, ultra-fast response, anti-interference ability and cost-effective. The sensor has 2.5mm 4-pole stereo audio male plug connector, which works perfectly with Sonoff TH10/TH16, S22 Socket.

Go shopping Sonoff Si7021(SKU:IM160712005)


  • Relative humidity and temperature measurement
  • All calibrated, digital output
  • Good long-term stability
  • No additional parts required
  • Ultra-low energy consumption
  • The sensor is fully interchangeable

Electrical Characteristics

Rated Parameters

Parameter Symbol Min Typ Max Unit
Voltage input VCC 2.2 3.3 3.6 V
Operating temp. & Measuring range Ta -40 - +85
Storage temp. Ta -65 - +150

Performance parameters

Parameter Condition Min Typ Max Unit
Operating range 0 100  %RH
Accuracy 0-80 ±2 ±3  %RH
80-100 See Figure 1
Temperture drift 0.05  %RH/℃
Stability ≤0.25  %RH/yr
Operating range -40 +85
Accuracy -10≤Ta≤85 ±0.3 ±0.4
-40≤Ta≤125 See Figure 2
Stability ≤0.01 ℃/yr

Si7021 hum figure 1.jpg

Figure 1. RH Accuracy at 30℃

Si7021 temp figure 2.jpg

Figure 2. Temperature Accuracy


Interface Description

It is recommended that the DATA pin use a 10K pull-up resistor and a 100nF capacitor can be added between the power supply pins (VCC, GND) for decoupling.

Si7021 Interface description.png

Audio Connector

Si7021 audio connector.jpg


Pin Name Description
1 VCC Power supply 2.2~3.6VDC
4 DATA Single bus, data port


Sonoff Si7021 Sensor Schematic