1. Power supply
2.7V～3.3V DC, two AA batteries are recommended.
If the DEV board has not been calibrated, the red LED will be ON after the board is powered-up.
If it has been calibrated, the LED will flash once at power-on and the buzzer will beep once.

2. Calibration mode
A smoke detector usually needs to be calibrated according to the operating environment.
This product has been calibrated at the factory.
(a) The way to enter the calibration mode is to short the BD connector pins on the board before power-on.
(b) Under the calibration mode, the red LED flashes once per second, and last for 4 seconds. If the calibration is successful, the board enters the normal mode. If the calibration is unsuccessful, the red LED will be ON.

3. Alarm mode
The product enters alarm mode when the smoke is detected. The buzzer beeps 3 times then pauses one second, and keeps cycling.

4. Test mode
Pressing the TEST button to simulate alarm mode once, the buzzer beeps 3 times.

1. MCU: Holtek BA45F5220, Smoke Detector Flash MCU, including datasheet, package dimension, etc.
2. Application Note: AN0540EN, BA45F5xxx Smoke Detector Integrated Analog Front End Application Notes
3. Application : Independent Smoke Detector Alarm BMAN5220DSA, including reference design, PCB layout, system architecture, etc.