Introduction: Mobile Phone Alarm for a Motorbike, Car or Anything You Want

I got fed up with normal alarms making a lot of noise, and no one taking any notice of them any more.

Also not knowing if anyone had messed with my bike because I was to far away to hear the alarm.

So I decided to make this alarm using an old mobile phone and a simple timer circuit.

The basic principle is if the motorbike is moved it will trigger a timer circuit,
which will send a 3 second pulse to a mobile phone, which will phone me to let me know that something has moved my bike.

This project is not just for a motorbike, It could also be altered you warn you about anything you want.
ie house, shed, car.

Step 1: Items Needed

1 old phone with speed dial.
1 mobile phone car charger.
1 555 timer chip
2 relays 12 volt
some tilt vibration switches.
some resistors and capacitors
some wire
a small plug and socket. (a phono plugs is ideal)
Some electrical tools and a little electronics knowledge.

Step 2: Modifiying the Phone

To start with I got hold of an old nokia mobile phone.
I removed the case and carefully removed the front panel that sits underneath the keypad. this was held in place by torx screws.

Then I wired two very fine wires to the button contacts under the digit (3) it doesnt mater to much which button you use but I used this number because its not used for my phone number and because it was close to the side of the phone so it was easier to bring the wires out.

When I had attached the 2 wires I then reassembled the phone and checked it worked ok. by shorting together the connector with a piece of wire. to make sure the phone will activate the digit 3.

Next you will have to go in to the phone menus and set up a speed dial on button 3 for your own mobile phone.

After I had done this I shorted the connector again to check the alarm phone will call my mobile.

Step 3: Timer Circuit

Next job was to make a simple 555 monostable timer circuit. You can find lots of useful information on building 555 timer circuits here.

the relay coil is wired between the 555 timer IC output and 0 volts.
you will need a diode across the relay to protect the timer chip.

The reason for the 555 timer circuit is to make sure when one of the sensors on the bike is triggered it will cause a 3 second signal that will trigger the phone.

It has to be 3 seconds other wise the phone will not dial the number.

I used a 13K resistor and a 220uF capacitor for R1 and C1 this gave me a 3.14 second pulse.
You may have to change the values slightly depending on the phone you use.

Step 4: Connecting It All Up

I then wired 2 wires from the relay contacts to a socket, and pluged the connector from the phone in to the socket wired to the relay contacts.

I was then able to check that the timer circuit will trigger the phone correctly.

The next job was to connect up all the sensors to the timer circuit.

This was just a matter of connecting some tilt switches and vibration switches in parallel to a relay. Which will trigger the timer circuit when movment is detected. They can be connected directly to the circuit with out a relay but I found using a relay gave me more options and a more positive switch.

You can have a many switches as you want.

In the past I have also wired my garage door in to the circuit.

Step 5: Fitting to the Motorbike

Then next job was to fit the timer circuit and relays in to a plastic box. And fit the parts on to my motor bike. And connect up the phone charger to the bikes ignition so when I am riding the bike the phone gets charged.

I had already fitted a bike immobiliser on the bike

so when the ignition is switched off the alarm is armed and when I reset the immobiliser, the power to the sensor / trigger relay is switch off. which will disable the alarm circuit.

I just wired the sensor / trigger relays 12v supply, from the immobilizer relay so when the immobilizers led is lit the alarm sensor relay in powered.

Step 6: Final Testing

after I had installed everything on the motorbike.
and wired everthing up.

It was just a simple job of trying to move the bike with the ignition off and seeing if the phone dialed my mobile.

if not you may have to make some fine adjustments to the movment and vibration switches.

you will be able to tell if they are activating the relay because you will hear it clicking on and off.

If the relay is being activated but the phone is not dialing you will have to check your wiring on the timer circuit.

and that is about it.

Step 7: Future Upgrades

Some future plans I have are.

modifiying the phone so that if anyone sets the alarm off. I can phone the bike back and set off an audiable alarm or siren.

Also to completly disable the bike to stop them being able to start it.

or even instead of a audiable alarm / siren I could have the bike broadcast a message like " please move away from this vehicle"