Instructables
Picture of Audible AC power-off alarm
07 - Blackout Buddy.JPG
I have a freezer that is located in the garage. During a recent renovation in the garage, the electrician was required to put all the circuits in the garage (including the
freezer) on a GFCI (Ground Fault Circuit Interrupter). He warned me that if the GFCI trips, there might be no indication inside the rest of the house that there is trouble,
and I could potentially lose the contents of the freezer before I notice the problem. He also said that to the best of his knowledge, there is no audible alarm available on
the market.

I checked around and could not find one, though I did find several rechargeable flashlights that can be set to automatically come on in the case of a power failure. One
such product is available at Radio Shack under the name "Eton American Red Cross Blackout Buddy" (part # 20-019) for $14.99.

The Blackout Buddy has three LEDs at one end and one LED at the other. There is a red switch on the top of the case that turns on the three LED end and an
"OFF/Auto" switch on the side that turns on the one LED end. The three LEDs will only light when the Blackout Buddy is disconnected from AC power and the top cover
switch is turned On. The one LED end is a nightlight and will only light when the side switch is in the "Auto" position and the room is sufficiently dark.

Radio Shack also sells several buzzers that could be attached in place of one of the LEDs. Once complete, when the LEDs light up, the buzzer also goes off.

Some of this project sounds like an advert for Radio Shack. Other than living in the Ft. Worth, Tx area, I have no connection with Radio Shack. I will not be
compensated in any way if you purchase any or all of these components at Radio Shack.

Of course it must be noted that making these changes to the Blackout Buddy will definitely void its warranty.
 
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nm8b made it!9 months ago

The buzzer is a little low from not having the proper voltage. On the next one i will remove all the LEDs and try running the power in series from each to get a little more voltage.

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Adam Manick4 years ago
You could also use a relay a battery and a buzzer so when the power goes off the relay activates the buzzer.
swake (author)  Adam Manick4 years ago
I was thinking about that when I ran across this thing. This already has the rechargeable battery, the charging circuitry, and the power fail detect all built in already. It's not loud enough to suit me, but I'm sure someone can and will point out a way to increase the volume.

Thanks for the comment.
Your welcome. I hate it when you post an instructable and nobody comments. You can’t learn that way. I rated your instructable 5 stars because you actually had the patience to reply to my comment. Thank you
I have a relay connected to a 25 amp switching power supply that is activated when the power is on. Power is siphoned off to charge a lead acid tractor battery and has a current limiting resistor to avoid over charging.

So, as the power is on the relay is on and the battery is charged and I can operate a VHF radio transmitter off the last 2 power taps. [there are 3 taps]

When the power goes off in the house I can still operate the radio because when the relay loses power the radio gets it from the battery.

It is a simple Un-Interruptable Power Supply. cost about $50 to build with all the power taps and stuff.