1. Sensor type: MEMS
2. Operating voltage: 3V~5V
3. Operating current: 18mA @3.3V
4. Detect VOC concentration (ethanol, formaldehyde, and toluene)
5. Detection range: 0~10ppm
   - Concentration level: 1~4 (default alarm level: 3)
6. Output mode: UART (baud rate: 9600bps) / STATUS
7. Factory calibration
8. Warm-up time: 180 seconds (default)
9. Fault detection function
10. Dimension: 59.3 x 33.88 x 20 mm
11. Net weight: 10.9g

The product has the same functions as the BM25S3421-1. The difference between them is that the product breaks out the BM25S3421-1’s pins to match BMCOM connectors and can directly connect to BMduino development boards, such as BM53A367A and BM18B367A.
You can use the product with other development boards, such as Arduino UNO, as well.

The product offers four levels to range VOC concentration from 1 to 4 (low to high).
The current concentration level, AD value, and alarm status can be outputted via UART interface every second. You can also monitor the STATUS pin to determine whether the alarm has been triggered. The voltage level turns high when alarming.

You can use commands to configure the alarm level and alarm exit level.

1. Alarm (default: level 3): when the product detects that the VOC concentration in the environment has reached the alarm level for more than 3 seconds, the alarm will be triggered.
2. Exit alarm level (default: level 1): when the product detects that the VOC concentration in the environment has reached the alarm exit level for more than 3 seconds, it exits alarm condition.

1. Place the product in the environment with the VOC concentration that you desire for alarming.
2. Read the concentration level via UART interface.
3. And then configure this level as the alarm level.

For example, if you desire to trigger the alarm at a 7ppm VOC concentration, place the product in an environment with a 7ppm concentration. Read the output concentration of 7ppm as level 3 via UART interface, and then configure level 3 as the alarm level.