Introduction: Toddler's First Clock - With Light-on Timer

About: Black sheep engineer, Chartered, and very silly. Currently living in the UK. I have been fortunate to have lived, studied and worked in Hong Kong, Norway and California. I believe physical models help people…

This guide shows you how to make interchangeable clock 'faces' - which can feature your kid's pictures, family/pet photos - or anything else - which you thought would be nice to change periodically. Simply clamp the clear perspex over the desired artwork whenever you fancy a change...

Better still, the numbers glow in the dark!

And if that wasn't enough - an 'Alarm' can be set to wake you with light (or a buzzer).

> And by chance, there is a Clock Competition, so please vote, if you like it <

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Why I did this project?

Why would anyone want a silent / light-up 'Alarm Clock'? How does that even work?! I know it sounds CRAZY!

Well, brace yourself - and enter the world of Toddler Logic - and it kinda makes sense...

  • My toddler previously woke up around dawn, (which is of course variable), asking, or rather - yelling:
  • Usually it was not :(
  • Turns out you can't simply tell him, "we get up at 7:30, ok, go back to sleep for 25mins please".
  • He can't tell the time, so a conventional clock will not work.
  • If I make an alarm clock, it will wake him abruptly (which as parents know - if your kid needs extra sleep, you try to let them have it. And god forbid you startle them awake (they get real cranky!) - so sound-alarms are out).
  • I needed a clock which:
    1. Allowed him to sleep-in if he was tired.
    2. If he was awake, it'd show him when it was time to wake up.
    3. Ideally, it would start to introduce numbers and spatial-awareness of a clock/time to him.

    Nice to have:
    - Fun/personal to his likes - e.g. Rockets & Space at the moment. (So, more likely to go with the plan).
    - Changeable (kid's get bored).
    - Able to see in the dark

So this was the result. Like most of my parenting, it's a v1.0, and is imperfect. But for now, it works nicely. Hope it's useful to some other people too!



Cardboard Boxes: I recommend 'thick' (2 ply) corrugated cardboard. Ask at a grocer for Apple Boxes.

Clock (silent):

Reed Switch (Normally Open variety is key):

Magnets (5x1mm): (annoyingly in a 50x pack, but perhaps available in hobby stores).

Resistors (suggest something close to 50Ohm for Green LEDs): (again, hobby stores may allow smaller pack purchases).

CR2032 Battery & Holder: and

Glow in the Dark Tape:


Soldering Iron:


Bosch Glue Pen: (not shown).

A Note for Non-Electronic Makers:
A quick note that I have listed the parts below. But frankly if you just want to make one of these, you can probably ask any nice electronics enthusiast to send you the parts. We are talking like under £1/$1 of parts all in here for this build. I happen to have a 'box of tricks' of stuff like this left over from projects, so I didn't shell out say £10 for everything. If not, I'd suggest buying a starter kit instead of each of these things, eg: Starter Kit and some Reed Switches.

Step 1: Create Your Masterpieces

I did about 5 paintings of handprints in different colours and styles, but could have been any any number of things.

TIP: In case you didn't know how to scribe a circle without a compass (I left mine in another workshop!), this is a good hack. Make sure it is about 2inch / 50mm larger than the sweep of the hands of your clock minute-hand, so it has room for numbers.

Once you have cut out your circle, keep the scrap, as it's useful as a visual 'frame' to select the nicest part of the painting or photos.

Cut out.

Step 2: Clock Mechanism

Drill or cut out a hole for the mechanism.

It might sound obvious, but don't 'ram' or push the mechanism through the hole if it will not fit. This can easily break it.

Step 3: Create the Alarm 'Wiper' Arm

I often talk about not using a ruler or taking precise measurements*. And here I simply used some tape reel to draw around, and the thickness of the rule.

*If you want to get into this style of modelling, it can really increase your speed an confidence, as rather than working from exact plans - you are adapting to the needs of the build/person/environment - and that can make a more intuitive design. e.g.

Create the 'wiper' as shown, which will set the alarm time.

Step 4: Install the Reed Switch

A reed switch uses two bits of nearly touching metal to make a contact only when pulled together by a magnet.

As this is a very precise thing, it's in glass (does not bend), but this means it is delicate. So take care when bending the legs.

Poke two holes at the right spacing of the resulting legs, and insert through.

Hold in place with some sticky tape.

Step 5: LED Resistor

You can find all manner of tables and formulae, but simply a 51Ohm resistor in for a Green LED is fine, if using the suggested 3V cell battery.

Solder onto the leg of the Reed Switch, and some wires to continue the circuit.

Step 6: Power

I added a Coin Cell battery, or CR2032, with a holder. This makes it easier to change, but some people just tape the wires to the battery - of course the latter is cheaper, but may be prone to coming loose. Your call.

TIP: Hobby shops or Hackspaces will likely have components like this, and may let you buy 1-off parts.

Step 7: Make Alarm Indicator

To add the arrow, to indicate the Alarm Time, I simply added a stack of card as shown.

I chopped off the excess to be flush. I liked the 'raw card' aesthetic, but you can also glue paper around it to make it more 'finished'.

Step 8: Install LEDs

I drilled 3 holes about 3mm diameter as shown. This can be done with a sharp knife or file, but drill is easier.

I then soldered the 3 LEDs in 'Parallel' - i.e. they all connect to the same wires, not in a circle ('Series'). This ensures they only need 1 Resistor, and have good brightness.

Lastly, I applied some Glue Gun to fix them in place.

Step 9: Test Function of Alarm

At this point, it was good to get kiddo involved...

There is something kinda 'magic' about having something light up when an object [magnet] moves near it. It's different for adults, so is really something for kids to try to figure out. If they listen closely, they can even hear the 'tick' of the Reed Switch fire on.

I then took the position that works best, and added the two magnets to the hour hand. I tested this at the normal speed to see if it did in fact work. It did! Nest step...

Step 10: Putting It All Together...

I disassembled the whole wiper assembly, and added the painting.

Note - slightly bend the hands as shown to ensure they don't touch.

If you're happy with this, it's fine to stop, as this is still cool, but I wanted to go further into the design...

Step 11: Rockets

Toddlers seem to be all about Rockets, and so it seemed perfect to add this to the second hand. Better still, the 'silent' clocks don't 'tick-tock', and their movement is smooth, so this works nicely for a smoothly flying rocket also.

I cut a section of the Glow In The Dark (GITD) tape, and drew out my rocket, and cut it out. For the holes, I could have cut them out with the scalpel, but the hole punch was simpler. (Link:

As you can see, I added a counterweight to the other side of the second hand.

Step 12: Clock Face - Transparent Plate

Although I drilled the centre hole myself (as the plastic can crack), I think this was a nice bit of work to allow my son to watch: The sawing of the disk.

The saw is terrific, (not ad/sponsored!), by Proxxon, and is a great company that does small machines for small workshops (like mine!).

I allowed my son to 'finish' the rough-sawn edge with a ruler. Scraping the surface gives it a smooth finish.

FYI: You can buy PC, PET or Acrylic (e.g.

Step 13: Numerals

I used my printer for the numbers (Font: DIN Standard).

In printer settings, most printers have 'flip' as a function to print in reverse. Handy.

I then used these as a guide to cut out my numerals from the GITD Tape, as shown.

I then marked the divisions of the 12 hours, using a Digital Angle (, though a protractor will do fine. Or even print out a guide!

I used some post-it notes to estimate the spacing from the edge of the numbers to the edge of the clock, as shown. I finally added some hour markers.

Step 14: Details

Never 100% happy, I did a second attempt on the hands. So you're welcome to learn from my 'mistakes' ;o)

I left some of the black around the clock hands visible, as this helped define them, like the numbers.

I also took more time to accurately counter-balance the second hand, as shown, as I noticed the hand looked like it was struggling mechanically a little as it lifted it up from 6-12 o'Clock.

Notes: I moved the magnets to the underside of the hands, and taped in place.

Step 15: Finished

I used a Sharpie/Marker to draw around each number - as this made it easier to read in normal light.

Note slight bending on the hands as before.

Step 16: Make It Yours!

Although this project began as a solution to try to help family matters, I like how it came full circles to just be a nice thing which will no doubt be a memory of childhood, but also able to be upgraded as my son's paintings develop - and of course when he wants his own posters, fan-art, etc. in time...

If you like this, please consider voting, and do check out more tips at:

Happy Making!


PS - I didn't make this as a Birthday Gift, but it strikes me that it'd be nice, with special photos and/or drawings, and will be in a memorable place.

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