Welcome to this simple page on how to build a monitored mains alarm that will call you by cell phone if your mains electricity goes out.

 Now to see the Mains power cut alarm-calling click here.

Why I designed this unit is because most people around the world use electricity the problem is if the electricity goes out or power lines go down this can cause all sorts of problems for every one

On the receiving phone have the name on your screen come up as mains out.

I have uploaded the video of the mains alarm calling my mobile as soon as the power cuts out look at the red light on the power strip next to the black adapter then the phone will activate and call out keep in mind it only calls the number locked in the Sim card..

The simple unit above is of a mains cut out alarm but this version does not sound an alarm it activates a cell phone and calls you to tell you there is a problem with the power at your premises.

Here is the Electronic Schematic and Block diagram of the circuit and pin outs below.


Only connect the two wires coming from your Modified Cell phone to the NC pin on your relay and C pin all relays have this on them.

When you have done all the Connections then check all your work and keeping the mobile switched off switch on the power.

You should hear a click from your relay as it turns on this has gone from a NC Normally Closed contact to a NO Normally Open contact then Switch on your phone and it should not trigger as soon as the power has been removed it switches back to a NC Normally Closed Contact and activates the Cell phone.





Now See the Silver band on the Diode Connect the Cathode to the + Pin on the relay it does not matter which way you connect the Diode to the relay coil as long as the Cathode is on the + line this is to stop EMP Electro Magnetic Pulse.

                            Zoo Med Nocturnal Infrared Heat Lamp

In the case of wildlife hospitals or vets small animals or birds may need to be kept warm as often the case we use heat mats or heat lamps like the ones in the photo above.

The problem is if you are not in the hospital at the time then you may not know the electricity has gone out this can be dangerous for small or weak animals as they may not live with out heat in the cold weather. 

This is why I designed this very simple detector so if the mains goes out then you will know about it in a matter of seconds also it will give you time to take action to save lives.

Why I used the cell phone is simple know matter how far you are away you should get a signal on your mobile phone unlike an alarm sounding you will hear the phone ring.

Like most heating systems now they use electricity to work with the boiler system they often need the electricity for the timer switch it can be very useful if you have a family member living at home and the weather is very bad like the cold and power lines go down to automatically be informed of the problem very good in the case of OAPs.

1). Items you will need to build your unit are one cell phone with speed dial or one touch dial on it. I just used the same one for the flood alarm and in the mains alarm Nokia 3310.

One cheap cell phone with one touch dial or speed dial on it the one in the photo below is a Nokia 3310 from e-bay click here. Or any phone that has one touch or speed dial on it will work fine.


You will all so need a cell phone opening kit see photo below or you may get one on ebay cheap from time to time. The kit above Contains useful tools designed to assist in the opening and repair of mobile phones especially suited to Nokia and Ericsson and Motorola phones but equally useful when attempting repair on other models click here.


One 12 volt 300MA power adapter for 240 Volts in the case of America Buy the power pack in your own country as you are 110 volts and two pin UK 240 volts 3 pin buy from any electrical shop.

On the next page we will modify our Cell Phone and add the numbers