Introduction: Safety Alarm Clock

I often find getting out of bed in the morning a bit tricky. When i have somewhere to be at a certain time, i get up pretty reliable. However when I want to get up it always seems that I manage to turn off my alarm clock before fully waking up.

Put it on the other side of the room? Multiple alarms? Sooner or later I acclimatise, and fall back to old habits...

This instructable will hopefully show you how to put your alarm under lock and key! This is the safety alarm clock.

Step 1: Things You Need

The chart below, I think does justice to the battle between my sensible conscious mind who wants to get up and do stuff and the selfish sleepy one who only wants to lie in bed.

The main point of my alarm hack was only to allow control of the alarm clock to me once the critical time had passed, once the sensible me was in control... I want the selfish sleepy me to be locked out of any alarm turning off privileges!

Things you will need

Cheapo digital alarm clock Get one with a back up battery if you want to do steps 6-8

Wire Cutters
Screwdriver to open alarm clock
Soldering iron
Wire ( double insulated core and jumper)
Project Box
Heatshrink/electrical tape
SPST Key switch (available from maplins for �3 in the UK!!!!)

for making the clock unpluggable you will need
a 2N3904 transistor
buzzer (6 - 12V)

got all these? no? doesn't matter, the only thing you really need for this is the key switch and alarm clock the rest I'm sure you can improvise!

Step 2: Open Up Your Alarm Clock

Before you open the sucker up, find out the specifics to control the alarm. For instance on my clock the alarm would not go off when the snooze was depressed, would be reset by the alarm set button etc... Try to figure out a way to the control the alarm on and off with a only a single switch.

WARNING : This may be a mains operated device, make sure you unplug it from the wall before even looking at a screwdriver!!! To be extra safe, leave it overnight uplugged to let capacitors discharge etc...

Looking inside it should be a tangled mess of wires, circuit boards and other such electrical jetsam. Don't be scared because most of that stuff is not important.

Now you need to find access points to the various buttons and switches that control you alarm. You want to try and figure a way of using one and only one switch to turn the alarm on or off.

Step 3: Wiring

For my clock I saw that all of the buttons that had any influence on the alarm shared a common ground! If your clock is based on any sort of microprocessor, this will probably also be the case. Even if the relevan buttons are far apart, you may be able to find a common ground point for them.

you can use a multimeter which has a continuity mode to test if two points on the circuit are connected. Or if no continuity mode, measure resistance, low resistance (ie zero) means a connection.

Step 4: Modifications

The solution for me was to put the key switch (more on this later) in series on the common ground, I would also lam the switch on the side so that it was stuck on the alarm on position. to make sure that the alarm was not on every day, I shorted the button for the snooze.

This means that with the key switch open the alarm will go off, and only connecting the common ground with the key switch turns it off.

Step 5: Key Switch

I had seen these key switches in maplins a few months ago and thought I must try to get them into a project. A SPST cost only 3 pounds!!! It is basically an isolated switch that can only be changed by inserting and turning the correct key. A SPST switch has two positions, connected and unconnected.

Drill some appropriate holes in a project box or other container to house the key switch. If your alarm clock has enough dead space, you mount the switch on the body. Mine didn't, so i had to mount as a peripheral.

add another hole to your alarm clock to thread out the wire from the common ground, adding a knot before you leave, to make sure no stress is put on the connections themselves.

Thread the wire into your project box (adding another knot) and hook it up to the solder pots on the switch. I added some super glue to the bolt, key chassis, project box connection to make it extra sturdy.

Step 6: Unplugging

The clock still has a weak point. When you unplug it, the alarm dies... I wanted a way to remedy this situation without resorting to dangerously fixing the plug in the wall...

Now this clock has a back up battery which preserves the clock settings when it is unplugged. I broke out my multimeter to measure the current coming from the battery when the clock is plugged in and unplugged.

A small 0.3mA current when plugged in, and a large 2.3mA current when unplugged. I wonder if i could use that change in current to switch another componant?

Step 7: Transistorise

Transistors are great at controlling a large current by a small current. In this case I will use an NPN transistor to allow current to pass to a buzzer when the clock is unplugged.

Under normal conditions the current drawn by the clock is insufficient to allow any current to flow C to E and so the buzzer is silent.

When 2.3mA is drawn by the clock, the circuit is effectively opened between C and E, and so the buzzer can sound!

Step 8: More Wiring

Wiring up the schematic in the previous page was a little tricky... since it was all inside the clock.

I used crocodile clips whenever i was soldering the leads of the transistor. they can be pretty sensitive to heat, and the crocodile clip serves as a heat sink safety net for you.

I wrapped all the exposed joints with electrical tape and cut an extra slot around the rim of the clock so that the buzzer could go outside. If there is spare real estate inside your clock you can leave it inside, there wasn't in mine...)

If you hold the transistor with the flat face towards you, the leads from left to right are emitter, base and collector.

If you want to check that everything has worked before putting it together, be cafeful. Plugging and unplugging whilst the case is open is potentially lethal. don't touch anything inside if you plug in the clock.

Step 9: Put It All Together!

Hopefully everything should go back together nice and snug.

Set the alarm, turn the lights out, chuck the key somewhere in the dark and fall asleep confident in the knowledge that the time you set on the alarm will be the time the you get up!


andrew101 made it!(author)2009-01-16

this is cool... but what if i hear the alarm and walk to the living room and fall asleep on the couch?

gowildchild made it!(author)2015-06-30

Get kids? ^.^

Eirinn made it!(author)2009-01-18

Have one in EVERY room of the house >=D

andrew101 made it!(author)2009-01-18

yea that would work. but the problem is i would shut off the alarm and fall asleep again

Eirinn made it!(author)2009-01-18

Well...someone suggested having a bunch of keys that look the same - get 20 or so keys that are identical by quick glance and put them all into a bowl. Before you go to bed put the real key into the bowl and shake it up. I doubt you'll go to sleep after trying out a dozen or so keys. If you still do then you might have to look into a medical solution o.o;

andrew101 made it!(author)2009-01-18

then id pull my bed from the wall and unplug the damn thing

rmurphy13 made it!(author)2013-05-21

Made a compact version with a cheap travel alarm clock. It's been great so far :)

2013 22:34.jpg
Cashew made it!(author)2009-01-28

If you need to get up, set the alarm, hear it and get up. Not too hard. Or ask your Mommy to wake you up. Or your spouse......

mushrooms401 made it!(author)2011-03-27

easier said then done my friend.i have tried that...i have failed...

adam+101 made it!(author)2010-01-25

no amount of self motivation can overcome sleep brain's selfishness!!

jules15 made it!(author)2010-09-05

yea for real.. its like you have no control over your mind that early in the morning

Spectre208 made it!(author)2011-01-26

So when you unplug the clock the buzzer goes off alarming you that the clock has been unplugged or when you unplug the clock the buzzer goes off when he has to, just like when the clock is plugged? This is a very awesome idea!

rustygray made it!(author)2011-01-20

Those who do not suffer from the dreaded sleep monster ( Z monster) have no idea how difficult it can be to shake the seratonin, melatonin induced coma from the brain.

This is a nifty idea. I also like the clocks that start lighting up the room 15 minutes early and by the time the alarm goes off they are fully bright.

Ceiling+cat made it!(author)2010-11-01

I think it would be a good idea to run a longer wire for the key box to another room so that you need to get up, walk to another room, and turn it off. That way the walking will help wake you up, and you can't just keep the key next to the clock and turn it off and go back to sleep.

johnston1991 made it!(author)2010-04-09

would be a great idea if it wasnt easier to just glue or take the snooze button off?

vandal1138 made it!(author)2010-04-08

1:38 = best time ever.

stephenniall made it!(author)2010-02-07

I see a tescos Radio alarm clock  !

I have the same one!!

adam+101 made it!(author)2010-01-08

Couldn't a wire cutter and/or wire stripper render the clock turnoffable?

Lowney made it!(author)2009-09-13

What YOU need is the "sonic bomb" alarm clock. My friend has REAL trouble getting up so he bought this. It sounds the alarm at an ear piercing 130 decibels! That's louder than a helicopter at take off! It also has a mini padded bass speaker which you put under your pillow.

toogers made it!(author)2009-09-16

dumb salesman.

Lowney made it!(author)2009-09-17

lol that's pretty much what he said when he told me about it minus the second sentence. I tried it out but I didn't like it. IT'S SCARY!

D.A.N made it!(author)2009-01-21

connect something to the snooze button that'll electricute you

Madrias357 made it!(author)2009-05-22

Camera capacitor under the button. I've done that to friends with "Snooze-button-itis" as a 'remedy' to slapping the snooze. First thing I did was cut the snooze-button into 3 parts, glue the 2 outer pieces, and place a capacitor and charging circuit in there running off of his 3volt battery backup. I've never heard of him hitting a snooze again after the first morning when he confronted me with, "You coulda told me the snooze would shock me!"

PCfreak made it!(author)2009-08-21

yeah like one of those prank shock pens

Madrias357 made it!(author)2009-08-24

Yep, but with a little more kick.

daywalker42 made it!(author)2009-01-20

and as for the whole unplugging could do something REALLY stupid and dangerous, and hardwire it into the socket to the point that it is all but unremovable. :)

bwpatton1 made it!(author)2009-01-22

I really wouldnt try that unless you are a qualified electritian. (I really cant spell) {I really dont like grammer either} Not to spoil the party but even 110 volts can be dangerous. (my dad is a qualified electritan) {again with the spelling}

daywalker42 made it!(author)2009-01-22

I was kidding, and as a legal disclaimer: Do not ever, ever try what I said......EVER!

Koolraap made it!(author)2009-01-31

I'm totally going to steal that line for my sig !

PCfreak made it!(author)2009-08-21

or as adam and jaime from mythbusters say: "Were What you call Experts , So Dont Try Anything You See At Home EVER!!!!!! i was watchin them and decided to post as a referance to daywalkers post

shaneomacmcgee made it!(author)2009-01-19

haha... knowing me, I'd just throw the clock across the room... good instructable, look forward to tryin it out!

Madrias357 made it!(author)2009-05-22

Easy solution to render a clock incapable of being used as a projectile: Bolts and apply some nice threadlock to the nuts when you put them on. I'd like to see the sleeper who can undo that in their sleep. If you can undo bolts while sleeping, use epoxy...

sierrabravo made it!(author)2009-07-08

i can't remember how many times my wife has told me i was undoing bolts in my sleep LOL! great instructable

john12692 made it!(author)2009-06-28

must build zzzzz still asleep zzzzz need to get up zzzz.......

alekszandor made it!(author)2009-06-28

This feels a bit like a alarmclock Jigsaw would build... :P Good idea though!

Yerboogieman made it!(author)2009-01-18

Every morning, all i have to worry about is HEARING my alarm, i even put a louder speaker on it (whole lot louder than the last) but i'm a heavy sleeper.

Madrias357 made it!(author)2009-05-22

I've tried things like that before. My current one is louder, and flashes an LED array to attempt to lure you from sleep.

Yerboogieman made it!(author)2009-05-22

I know something that gets me up, i use jetaudio's alarm clock and the beginning of Tool - Eulogy. Works like a charm.

nolte919 made it!(author)2009-01-16

Great Instructable. Just so you know, in step 3, in the first image, you have an image note that's impossible to get to. If a smaller note is completely inside a larger note then the smaller one is impossible to get to. As soon as your mouse goes over the outer one, the inner one disappears. Or maybe it's just me that has this problem. I use Firefox if that makes a difference.

lukeyj15 made it!(author)2009-03-08

i got the same problem

xproplayer made it!(author)2009-01-16

it says This pin is the common ground for all of the buttons i am interested in. follow the silver to see it connects to all the buttons

stephenniall made it!(author)2009-01-29

I think it'd be cool if you added a emergency Momentery push switch so you turn the key and flick the switch then press it ! lol

Sorta like that but not a flick switch

dylan2106 made it!(author)2009-02-04

Yes! I have been looking for a project that will incorporate the missile style switch cover for a while. Perhaps v2 will incorporate it!

twist2b made it!(author)2009-01-22

I realize your method is easy as well :P But, you could have cut the line from the snoose back to the buzzer, making the lock the new path of flow... make the key a switch and your done. :) Still, this is an awesome project. Bravo for the idea!

dylan2106 made it!(author)2009-01-29

problem was that the other buttons, "set alarm" and "set clock" and "sleep" also caused the buzzer to stop...

Plasmana made it!(author)2009-01-24

That is actually a very good idea, I might try that... Another thing, you have the exact same multimeter I have! :-O

dylan2106 made it!(author)2009-01-29

it's a goodun!

randumbum made it!(author)2009-01-27

Great idea, and a relatively straight forward hack on any cheapo digital alarm clock. Thanks.

radiobath made it!(author)2009-01-25

I have the exact same issue. I used to use two alarm clocks and my cell phone. But I managed to sleep through all of that. So then I got FoxyTunes and I would use Norma Jean (read: hardcore screaming at the beginning of the song) as my alarm. I'd turn my speakers up all the way, put on a movie at low volume to go to sleep, and then 7 AM would roll around and I'd wake up through sheer terror. Haven't been late for work since.

Arghus made it!(author)2009-01-24

I have got the same problem, i tried it all, even putting the alarm clock on a table near my feet, but no matter what, my unconscious mind was able to get me up and turn it off and go back to bed .. so instead of wiring a key lock like you did, i separated the speaker, so i got the alarm clock in the drawer of the bedside table with the speaker on top, drawer locked with key, to turn it off i have to take the key , open the drawer and then i am able to snooze or turn it off.. Great idea Btw :D

About This Instructable




More by dylan2106:Safety Alarm Clock
Add instructable to: