Hi,
I have a 2010 caravan with a Thetford N110 fridge installed.
Due to the location of the control buttons on the front of the fridge, they frequently get inadvertently pressed.
This can result in a warm fridge!
When a fault occurs, a blue led (on the front of the fridge), flashes about 1 per second.
When the fridge is operating correctly, the led is lit constantly steady.
How can I wire in a piezo buzzer that will sound when the led flashes?
I don't want any sound when the led is steady.
Location of buzzer doesn't matter as long as it's reasonably audible in a quietish caravan.
Any ideas please?
Many thanks,
4Musky

 

Welcome to AAC.

The first thing that comes to mind is to rig the buzzer so it sounds when the LED is off. That way, it would normally be silent but if the flashing starts it will beep alternating with the indicator.

It would require a simple circuit with a single transistor. We have a few prolific circuit producing members who will provide schematics and simulations so I suspect you will get a candidate as soon as the thread is discovered by the circuit boffins.

 

Is it possible to put a plastic cover over it to prevent accidental touching?

 

This is a simple circuit that will operate the buzzer when the LED on the frig is OFF.
The photocell would have to be mounted and shielded to only receive the light from the LED.
Component values will vary depending on what voltage is available for the supply.
Refinements may be necessary if using battery power.