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Power outage alarm

EdgarAndre

Hello, I am new to electronics and I would like to make a power outage alarm with a Raspberry Pi Pico 2 circuit that I bought as a kit. The Pico would be connected via USB and when a power outage occurs, a two-hour timer would start and after these two hours an alarm would sound. The circuit would be powered by a 9 volt battery for two hours. The alarm could sound for one minute with a bib every two seconds. If the power comes back on before two hours, I would like the timer to reset. Do you have any solutions to suggest or examples of circuits adaptable to this project? Thank you very much for your help.

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  • 0

    I just returned the freezer and refrigerator alarm I bought on Amazon because one of the sensors wasn't working. I also reread the comments from other dissatisfied buyers and there seem to be reliability issues with the thermometer's accuracy and overall build quality. However, I found a circuit that seems interesting and I'll give you the link. If you have the time, I would appreciate your feedback. Leaving a light on isn't ideal, but since I would only be using this alarm at night for severe storm warnings, it's acceptable. I will obviously use the smallest Dell bulb possible.https://www.instructables.com/Power-Outage-Alarm/

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  • 0

    I just returned the freezer and refrigerator alarm I bought on Amazon because one of the sensors wasn't working. I also reread the comments from other dissatisfied buyers and there seem to be reliability issues with the thermometer's accuracy and overall build quality. However, I found a circuit that seems interesting and I'll give you the link. If you have the time, I would appreciate your feedback. Leaving a light on isn't ideal, but since I would only be using this alarm at night for severe storm warnings, it's acceptable. I will obviously use the smallest Dell bulb possible.https://www.instructables.com/Power-Outage-Alarm/

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  • 0 in reply to EdgarAndre

     I'm sorry to hear that you had to return the sensor.  It has a 4.3 of 5 rating with over 2,500 reviews.  Also remember that people are much more likely to leave a negative review than a positive one.  The system is skewed towards the negative.

    You can replicate what this was going to do with you Pico and a temperature sensor - such as the DS18B20, DHT11, DHT22 or LM35.  I'd still go with a small piezo alarm.  Since it seems like you really want to build one, pick up a LiPo battery and charger module (TP4056).  Use that to power the Pico and charge the battery.  A single 18650 battery should be sufficient.  With normal power available, the system runs off of the wall wart.  If the power goes out, it runs off of battery.  The only downside is the cable that goes into the fridge and/or freezer for the sensor.