Help to modify a friend's alarm clock to make it much much louder

Thread Starter

setsquar

Joined Oct 11, 2012
36
A friend of mine who is quite deaf
has asked me modify his alarm clock to make it much much louder
Its a battery quartz Bell type but it just rattles instead of ringing
the bells are driven by a small electric motor and I was going to remove that and connect the output to drive a small piezo alarm sounder
however the output voltage is only 1.5volts
the alarm sounder has a built in 9volt battery and works as a make/brake door bell type circuit
so I have +and- 1.5 volt coming out of the clock
and +and – 9volt input on the sounder
I had intended to use a small relay on the clock to switch on the sounder but not enough volts to drive one.
Your help would be very much appreciated
 

Tonyr1084

Joined Sep 24, 2015
6,374
I think perhaps an opto-isolator can act as a trigger controlling a higher voltage, one that can easily switch a relay. The relay - in turn can drive your modified alarm. An alternative will be to use an Op-Amp to boost the output voltage. You'll still need an external voltage source.

As a silly thought I imagined an old spark coil from a car and a few electrodes just below the sheets. Blind - deaf - doesn't matter; you're GOING to get up.
 
Last edited:

MisterBill2

Joined Jan 23, 2018
9,543
A volt and a half should be enough to bias a transistor on and that can control e bit more power. No need for an isolater if you stick with safe voltages. Probably using a transistor rated at one amp will be enogh for that alarm bell running on 12 volts.
 

crutschow

Joined Mar 14, 2008
27,960
How about adding a sub shaker to the bed, such as this. :)
That should work even if he's totally deaf.

It could be powered by a 6 to 12V transformer of the appropriate current rating (the shaker is 8Ω) to give a 50/60Hz shaking of the bed.
A transistor operated relay from the alarm signal (or a programmed smart plug) could switch the mains power to the transformer.
 

Tonyr1084

Joined Sep 24, 2015
6,374
My wife would shut it off and then go back to sleep.

Now, a spark coil and some conductive pads under the sheet - - - That'll get you out of bed.

I don't have a problem getting up. In fact, I'm often up before the alarm rings. The wife, on the other hand, has learned to shut the alarm off in her sleep. So I made her put her alarm clock where she couldn't reach it without getting out of bed. Yeah - like that made any difference. She'll shut it off and then plop back in the sack.

I've seen video's of beds that tilt up to literally drop you off the foot of the bed.

But seriously - - - an old car horn should be loud enough. Triggered from a transistor and relay, you have a winner. But not if you're in an apartment building or condo's. Your neighbors might be the ones waking you up. Or calling the police.
 

Thread Starter

setsquar

Joined Oct 11, 2012
36
A volt and a half should be enough to bias a transistor on and that can control e bit more power. No need for an isolater if you stick with safe voltages. Probably using a transistor rated at one amp will be enogh for that alarm bell running on 12 volts.
so would this work if so what resisters would be needed given the voltages
 

Attachments

Tonyr1084

Joined Sep 24, 2015
6,374
I like how the headboard and footboard look like tombstones.

Wondering what kind of worm could be used that you could tie a string to and not bisect the worm. And that canon ball would need to be closer to the fulcrum of the board. Otherwise it would just fall and pull the cork.
 

MisterBill2

Joined Jan 23, 2018
9,543
I like how the headboard and footboard look like tombstones.

Wondering what kind of worm could be used that you could tie a string to and not bisect the worm. And that canon ball would need to be closer to the fulcrum of the board. Otherwise it would just fall and pull the cork.
The fact is that Rube Goldberg systems do not ever need to be based in reality. Just consider the small balloon supporting the brick, and staying in place long enough to be useful. Much less believable than the worm, which is actually a plastic bait type of worm. Then consider that revolver hanging by a string tied around the cylinder, and how would it stay aimed for any length of time? Many of these creations could never be assembled in the real world, but only in the 2-dimensional cartoon space.
 
Top