mc145010

[fpgiovanini]

According Figure 8. Typical Battery-Powered Application in the MC145010 DATASHEET.

There is no reflection inside the chamber but sunddenly the LED start blinking several times nonetheless the output I/O was not triggered.

which conditions make the LED this behaviour? 

where this information is available?

[JozefKozon]

Dear fpgiovanini,

the LED can blink under several conditions not related to smoke detection:

1. Low-Supply Voltage Condition:

   • The chip periodically checks the supply voltage using a pulsed load current from the LED pin.
   • If the voltage drops below a threshold (set by external resistors), the LED flashes alongside a beep or chirp to indicate low battery.

2. Degraded Chamber Sensitivity:

   • The IC performs periodic checks for chamber sensitivity degradation.
   • A beep occurring halfway between LED flashes indicates this condition.

3. Push Button Test Mode:

   • If the test button is pressed, the IC enters high-gain mode and may cause the LED to blink as part of the test sequence.

4. Power-On Reset or Internal Monitoring:

   • Upon power-up or during standby, the IC may perform internal checks that momentarily activate the LED.

With Best Regards,

Jozef