Introduction: Extreme Loud Alarm Clock
Normally your bed alarms have 20-40 db sound. which is enough to wake up most people. But for some of us it barely shakes our eardrums while we are sleeping. This is for those lucky sleepy heads.
Step 1: INTRODUCTION AND EQUIPMENTS
This mod is intended for those who love their beds more than their jobs/classes. those bed bugs ( like me) who don't want to get up from their bed , no matter how much the alarm screams., who doesn't even hear an alarm.
so whats the solution?? of-course we may get up if some one drops a grenade near our bed, but since a grenade is pretty hard to find on local stores and worth lot of money for daily usage, i present a little hack which can do almost same.
Be warned before you proceed, this little sucker is so loud, that you can wake up your buddy next door...and the evil thing is.. you can make it even louder.
THINGS YOU NEED
1) Analog / Digital alarm , any model can do the trick, as long as it have a piezo buzzer as alarm speaker.
2) 90-110 db door open alert buzzer ( in fact any high db alarm- like those from personal protection alarm can work) like the one shown in picture.
3) simple soldering skills( lil bit electronics skills needed if you want it make more louder)
4) Philips screwdrivers for opening things, super glue , and essential components and wires.
Step 2: Understanding Your Alarm Clock.
Normally every alarm clock, whether it is digital or analog, have a power supply, which may be from some battery source, and then a clock mechanism ( digital circuits for lcd/led clocks and analog for analog clocks ( here i use a cheep analog model, but this can work with almost all digital or analog models), and a buzzer (marked as BZ) to produce sound.
HOW IT WORKS?
The clock's circuit ( inside the mechanism assembly) will trigger a contact/electronic switch on the preset time which opens an electrical signal ( may be even tunes) to the buzzer, which then causes the buzzer to produce corresponding sound. But since the whole thing is powered by single or double AA /AAA battery, the voltage is about 1.5-3 volt normally, and it is not enough to give a high output volume from the buzzer. also the normal buzzer inside these alarms are not designed to give high db ( volume) .
so what we are going to do is to boost the normal voltage to higher voltage and then use it to drive some high db buzzer.
Step 3: Understanding the High Db Alarm(buzzer)
Most high db alarm contains a tone generator + reed switch (magnetic switch which activates/deactivates when a magnet is placed near it) + a chock( which is basically a step-up transformer which boost the input ac signal by several magnitudes) + a high db piezo buzzer plate + power supply batteries( normally some button cells for space saving)
In case of a door alarm, there are two units , one is the alarm itself, and other is a magnet, magnet is generally attached to the door, and alarm is attached to the door assembly, so that when door is closed the magnet is closer to the alarm unit.
when the alarm is activated and door is closed, the reed switch is closed/ opened and the circuit senses it, and is in standby mode. but when the door is opened, the reed switch changes its initial position, which triggers the alarm circuit , and it produce some kind of audio signal, which is feed to the chock, and the chock amplifies that ac signal ( every audio signal is ac) and feeds the output to the buzzer. since the signal, which the buzzer gets is high voltage ac, it vibrates more vigorously and produce a loud tone.
Step 4: Joining the Two for 60-70 Db Alarm.
Salvaging the required parts from high db buzzer and alarm clock
1) We only need the chock and buzzer plate from the high db alarm, the chock have 4 legs, two of which are attached to the circuit board, and two of them is attached to the buzzer plate itself with wires.
2)Open the alarm unit and desolder and carefully disconnect the chock from the circuit board, and desolder the rest of power wires to the circuit board, and take the board out, we don't need it for now( you may use the board itself for some other projects)
3) don't disconnect the chock from the buzzer, keep it like so.
4) Now open the clock and find the buzzer inside it, it have two wires attached to it. desolder and disconnect that wires, now make a small grove / hole on the side of the body of the clock, and pull out out those wires through it, now you can re assemble the alarm clock.
5) solder those two wires to the two pins of the chock ( the two pins we disconnected from the circuit board on step 2). you can use / make small grove on the side of the high db alarm for the passage of wires.
6) now close the back cover of the alarm. and check the working by adjusting the alarm time and clock time.
7) If you have done everything properly, you can hear an alarm which is several times louder than your normal alarm sound.
8) use some super glue to attach the alarm unit to the clock. and now you have a louder alarm clock.
Step 5: For the Devil in You.. an Even More Louder Version (90-110 Db)
Now if you want to wake up the people next door, try this.
1)For this you need some knowledge in electronics; For you need to make a transistor based switch, which activates and pass a higher external drive current-voltage to the chock from an external battery source ( u can salvage the button cells in the battery compartment of the high db alarm itself ( which is 3*LR44 button cells, which will give 4.5 volts)
2) Now you need to find the signal and common lines which goes to buzzer of the alarm clock. some manufactures use a common ground and some others use a common positive line. ( use a continuity tester or multi meter to find the common line with the clock battery.)
3) if you have a common negative line , the other wire will have positive signal, but if you have a common positive, then the other line will have a negative signal.
4) If you have common negative , use an NPN transistor switch ( like the one in my circuit, in the picture)
5) If you have common posistive, use a PNP transistor switch ( google it, i am too lazy to draw)
6) now join the negatives of external battery and clock battery and connect it to the one leg of the chock ( positives if you have common positive), and feed the signal line to the base of the transistor, connect the collector of the transistor to the other leg of the chock, and the emitter to positive of external battery ( negative if you have common positive).............. weewwww... don't get confused , refer the circuit in the picture.
7) If you have done this correctly, you will get a much louder alarm, because the drive current-voltage for the chock is now taken from the external battery.
NB:- If you use a 9v PP3 battery as external battery you can make a ear shattering alarm, and possibly wake up your neighbors too..... EVILLLLLLLL....
Step 6: DON'T DRAG ME INTO THE CONSEQUENCES OF YOUR STUPIDITY
Like any other projects, the author ( hehe.. its me , in this case) is not responsible for any damage or potential hazard you may fall into, or fired from jobs,classes etc. , angry neighbors, buddies, etc.. dead dragons or humans.. or loss of money time or any thing..
literally i am not responsible for anything you may end up by trying to build this... for me its working and and i have successfully earned few complaints from my next door buddies...so you can get some too.. if you can make it.
We have a be nice policy.
Please be positive and constructive.
Have you made a mistake with the transistor is this a pnp as the emitter is connected to + battery . you said it was a npn