Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Detection Gas	Formaldehyde (CH2O)
Model Number	CJSH22-CH2O
Operating Voltage	3.3V - 5V DC
Output Signal	UART / PWM
Response Time	< 30 seconds
Power Consumption	< 50mW
Operating Temperature	-10°C to 50°C
Dimensions	20mm x 15mm x 8mm
Sensor Life	> 5 years
Application	Air Quality Monitoring, Smart Home Systems

6 reviews

Anonymous

Mar 27, 2026

Rating: 5/5

Low power consumption as advertised

I am using this in a battery-powered device, and the low power draw is a game changer. It detects formaldehyde spikes quickly when I bring new furniture into the room.

Anonymous

Mar 22, 2026

Rating: 4/5

Compact and effective

Very tiny form factor which fits perfectly inside my custom enclosure. It reacts well to alcohol-based cleaners too, so keep that in mind during testing.

Anonymous

Mar 09, 2026

Rating: 5/5

Perfect for my air quality project

This module is incredibly small and easy to integrate with an ESP32. The readings seem consistent when compared to my standalone meter. Great value for the precision offered.

Anonymous

Mar 07, 2026

Rating: 4/5

Good sensitivity, fast shipping

Works well out of the box. It took about 2 minutes to warm up, but then the data stream was stable. Deducting one star because the documentation could be more detailed regarding calibration.

Anonymous

Mar 05, 2026

Rating: 5/5

Excellent precision for the price

I was skeptical about the 'high precision' claim at this price point, but it holds up. The voltage requirements are flexible, making it easy to power from various sources.

Anonymous

Mar 04, 2026

Rating: 5/5

Reliable industrial grade component

Bought five units for a prototype. All of them performed identically. The UART output is clean and easy to parse. Highly recommended for professional prototypes.

5 FAQ

Q: What is the communication protocol used by the CJSH22-CH2O?

A: The module supports both UART (TTL level) and PWM output. You can select the mode via the configuration pins as described in the datasheet.

Q: How often does the sensor need recalibration?

A: Under normal operating conditions, the sensor maintains calibration for over a year. For critical applications, we suggest an annual check against a reference gas source.

Q: Can this sensor detect other VOCs besides formaldehyde?

A: While optimized specifically for Formaldehyde (CH2O), the sensor may show some cross-sensitivity to other volatile organic compounds like alcohol or benzene, but the primary output is calibrated for CH2O.

Q: Is this suitable for outdoor use in rain?

A: No, this is a bare module and is not water-resistant. It must be housed in a protective enclosure with proper airflow if used in outdoor or humid environments.

Q: Does this module require a warm-up period before giving accurate readings?

A: Yes, we recommend allowing the sensor to warm up for approximately 2 to 3 minutes after powering on to ensure stable and accurate baseline readings.

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