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NDIR CO2 Digital Sensor BM25S3321-1

US$18.00

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BM25S3321-1

DESCRIPTION

The BM25S3321-1 is a CO₂ (carbon dioxide) detector. It uses the NDIR (non-dispersive infrared) method to calculate the concentration of carbon dioxide from measuring the infrared value that has been absorb by carbon dioxide. Each sensor has been calibrated at the factory.

The BM25S3321-1 provides two communication interfaces, PWM and UART, to read the CO₂ concentration. You can use the UART interface to modify multiple parameters, such as calibration value, detection range, auto calibration setting, and so on.

It also provides three calibration methods, manually calibrating, command calibrating and auto-calibrating. You can calibrate the module according to your requirement.

Product information

Dimension: 32 x 20 x 16 mm
Net Weight: 5g

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PRODUCT FEATURES

Operating voltage: 5.0V ±0.1V
Average current: < 40mA @5V
Detection range: 400ppm to 5000ppm
- Resolution: 1ppm
- Accuracy: ±(50ppm +5% read value)
Interface: UART (3.3V logic, 9600bps) / PWM
Interface level: 3.3V
Module service life: 5 years
Warm-up time: 60s
Response time: T90 < 120S
Temperature compensation
Operating humidity: 0 to 95%RH (non-condense)
Factory calibration

PIN DESCRIPTION

CALIBRATION DESCRIPTION

The BM25S3321-1 provides three methods for zero calibration.
The zero calibration means calibrate the module to the concentration of 400ppm.
Ensure the module has been operated in stable carbon dioxide environment of 400ppm for at least 20 minutes.

Manually calibrating
Pull low the HD pin for at least 7 seconds to initiate zero calibration.
Command calibrating
The module provides zero calibration command (command W01) and span point calibration command (command W02).
The zero calibration should be completed before the span point calibration.
Ensure that the module has been operated in a stable carbon dioxide environment for the concentration that you need to calibrate for at least 20 minutes.
Auto-calibrating
The module provides auto-calibrating command (command W05).
After enabling the auto-calibrating function, the module determines the zero point itself during a period and calibrates to the concentration (400ppm calibration).

PRODUCT FAQs

Question 1
What does the "response time: T90 < 120s" mean?

Answer
The response time of a sensor is usually quoted as the time to reach a proportion of the target value.
For example, T90 30s indicates the sensor will reach at least 90% of the final value within 30s of the measured property being changed.

Question 2
Does the module have been calibrated for two point at factory?

Answer
Yes, the module has been calibrated for zero calibration and the calibration in a stable carbon dioxide environment of 1500ppm concentration.

Question 3
Would you recommend enabling or disabling the auto-calibrating function? Why?

Answer
The auto-calibrating means that the module calibrates to zero point (400ppm) automatically itself.
The module keeps operating for a period, measures the zero point according to the carbon dioxide concentration in the environment and calibrate itself automatically.
The calibration period is 24 hours after powering on the module (it calibrates once every 24 hours). The function is suitable for offices and homes, but it is not suitable for greenhouses, farms, and cold storages.
We recommend you disable the auto-calibrating function in these places, and operate the zero calibration regularly.

Question 4
Does the module operate auto-calibrating based on 400ppm (as zero point)?

Answer
Yes, the zero point of auto-calibrating is based on 400ppm.