Memory Box with lid-triggered audio

After having our son, my partner wanted me to make her a memory box where she could keep all the trinkets and keepsakes from his birth.

As it is something of an old stereotype that such things would be kept in an old shoe box, I wanted to mimic that aesthetic.

The box is made from iroko, sides of approx 1cm, joined with box joints.
The base is simple hardboard, rebated into the sides.

I didn’t really want to add hardware such as hinges as I felt it would detract from the shoebox aesthetic, so I opted for a simple lift off lid.

The lid itself is made from a thicker piece of iroko, with trim added around the edges.

In order to provide a good friction fit, a piece of plywood, wrapped in t-shirt fabric, matching the boxes internal width and depth was added to the lid. This holds the lid on without rattling around, and incidentally hides the “bonus feature” of the box.

The bonus feature

Of course I can’t do anything normal like just make a box.

During his first few weeks, whenever our son sneezed, he would follow it up with a little noise that sounded like he was saying “oh..”. Of course it was incredibly cute and a memory we want to cherish forever.

What my partner didn’t know at the time, is I had managed to catch this on video, and I wanted to surprise her with it. 

A few years ago (around 2015-2016 I think), Sainsburys brought out a Christmas biscuit selection box which included a gadget for recording a message that would play when the biscuit tin was opened.

Somewhere along the line somebody I know must have got one, I scavenged the gadget from the tin once it was empty, and it spent the past few years sat in my electronics junk drawer, waiting for a project to be used in.

 

 

The circuit board is clearly designed as a disposable product – it is powered by 3 button cell batteries, which are riveted to the PCB itself. Whatever microcontroller powers it is hidden under an epoxy blob, and the only other notable features are a small microphone, speaker, a light dependent resistor (which is how it detects if the box is opened), and a small switch used to start and stop recording.

First thing to do was to drill out the rivets and get rid of the dead batteries.
Rather than replace them with more button cells, I opted for wiring in a AAA battery holder, I just had to follow the PCB traces and connect it at the right point.

 The microphone is pretty much as crap as you would expect for something of that size in a ostensibly disposable product, so I needed a better way to record the audio.

To do that I replaced the microphone with a 3.5mm jack and coupling capacitor. Once I’d copied over the recording, I removed that as well to save space, and also removed the record button to avoid overwriting.

 

Then it was simply a matter of hiding the electronics in the box. This was done by carving out a hollow in the middle of the lid. The ‘inner lid’ of plywood that was also used to create a friction latch, added sufficient depth to the lid in order to hide the battery and PCB.

The underside of the lid with hollow for PCB/battery and speaker.

The t-shirt fabric that covered the inner lid also hid the circuitry, while also allowing enough light to pass through to activate the recording.

Ring Box part 2

In my last post, I showed the process of building a small wooden engagement/wedding ring box. Obviously it needs some lining to be fit for use.

The original sketch had a note next to it about an LED in the lid which I definitely wanted to do, but there's some space constraints to consider, namely where to fit batteries in the box while still keeping the traditional ring box appearance.

To create the padded sections, I used some leather offcuts, rolled up with the suede side exposed. The front "pad" is literally just that.

The rear pad has rolled from a 'L'-shape piece of leather, like in the illustration. When rolled, this creates a small hollow in the tube, where the batteries will reside.

Electronics
The circuit is very simple. A white LED in the lid of the box will be powered by two G3A batteries (v. small cell batteries), and triggered by a normally closed reed switch. (i.e. putting the switch near a magnet breaks the connection).

The reed switch is carefully placed in the hinge near a small magnet (hidden under the leather), so that when the lid is closed, the magnet holds the reed switch open.


G3A is not a common type of battery, I just happened to have a lot that I recovered from some recycled electronics. As a result I couldn't find a battery holder for them, so I adapted this CR2032 design from Thingiverse.

The battery holder. View on Thingiverse.

The LED itself is just mounted with hot glue, angled down toward where the ring will be situated. The wires run down the inside of the lid to the hinge, where the reed switch is positioned.


On the base side of the hinge, is the small magnet which triggers the reed switch.

All of this is covered by another strip of leather, which is glued - suede side up, to the inside of the lid, and runs down to the hinge, overhanging it into the base (see photo). This overhang is tucked behind the leather roll containing the batteries, hiding all the wiring, but meaning it is still accessible should the need arise (to change the batteries, for example).

A post shared by Anthony (@darkmidnight_diy) on Jul 6, 2018 at 7:46am PDT

The finished box

A post shared by Anthony (@darkmidnight_diy) on Jul 10, 2018 at 12:40pm PDT

A moving shot to try and illustrate the sparkling of the ring under the LED light.

Ring Box part 1

Between the sign and the cake stand, and now this, my projects seem to be very wedding-focused of late.

Originally this ring box was going to be a project for the same wedding as the other two, but unfortunately due to various circumstances, it didn't materialise in time for the big day.

So when my brother got engaged recently, I gave him the designs I'd already sketched up and he picked this one for me to build for him.

A post shared by Anthony (@darkmidnight_diy) on Jun 23, 2018 at 3:01am PDT

The woodworking component of this is pretty straightforward.

The wood I used is oak for the main body, and a darker hardwood (of the well-known species 'offcuttus miscellanei') for the sides, to provide a nice aesthetic contrast.

I was referencing an existing ring box for scale,
and purely by coincidence, the wood sections
I was using were a spot-on size.

Because of the small scale of the box, it's difficult to do any advanced joinery, so the pieces are simply glued, but the wood is light enough and small enough that the joints are still sufficiently strong.

Once all the glue-up is complete, it's off for some sanding to ensure everything's cleaned and squared up, leaving us with a sealed hollow cube.

Some work in progress shots of the ring box. This was certainly one of those projects that at times seemed a mess and you had to keep faith it'd look good when it's done. #diy #maker #woodworking #handmade #wedding #ring

A post shared by Anthony (@darkmidnight_diy) on Jun 24, 2018 at 3:57am PDT

With that done, the cube needs to be cut. Typically, it seems, most ring boxes are about 50-50 (half the height in the lid, half in the base). However, I've opted for a 25-75 split, leaving a larger base, as the plan is to include a small LED light, and I'll need space for batteries and wiring.

I took the hinge from the existing ring box I was using for reference. To fit it, I drilled out a small cavity in the back of the box for it. As the wood is only about a quarter inch thick, this was the most nerve-wracking part of the whole project.
Once I got it fitted, I sanded off the top of the base-back and the lid, so that their edges didn't collide when opening.

When satisfied with the opening mechanism, I epoxied the hinge in place.

Then the rest of the exterior is just a case of shaping with the sander and a coat of danish oil to finish.

Then onto the interior...