Music & Lights in Childproof Case

Music + light show in childproof case.

Video here: Video: Child proof music player + lights

Why make this?

A few years ago I made a much more complex machine for a disabled child that contained an iPod where tracks could be selected simply by placing cards containing unique wireless codes (RFID) on the top of the box. The idea was that little hands that could not operate mp3 players or CD player controls, could still choose their own music. The instructables for those projects are here: Magic Music Table and here: Tangible music player

This project is along the same lines but much more straightforward to make - carpentry mainly, no modification of electronics at all.

It provides music from an iPod inside simply set to "shuffle play" with a light show, all in a secure child-proof box. I made it for a residential home, where it is a big advantage to be able to show that nothing inside has been modified in any way whatsoever in terms of the electronics.

What is inside?

An extension power bar at the back has 3 things plugged into it: i) A set of speakers for a desktop computer comprising two small speaker boxes and a larger subwoofer box for good bass, ii) An off the shelf sound to light unit consisting of 6 coloured lights, these are LED so do not get hot even inside a wooden case. iii) Power charger for the iPod.

List of components

1/2 inch thick marine ply (stronger than MDF etc).

Some lengths of 4inch by 2inch timber or similar.

Lots of screws

A set of speakers for a desktop computer. In this case I used a set from Logitech consisting of two small speaker boxes and a central subwoofer box (teenagers like lots of bass with their dance music).

A low cost LED based sound-to-light unit.

An iPod of some sort that can be set to shuffle play.

An extension lead with short lead and at least 3 sockets on it, prefer individually switched sockets. If for a place like a residential home, they may insist on it having a moulded-on plug.

Some galvanised steel mesh for making speaker grilles.

Polycarbonate sheet for the top surface.

Here are the computer speakers I used.

The subwoofer fires downwards and also has an open port on its rear surface.

Box is made any size you want. The 2 x 4 timber is used for the uprights in the corners. The panels are joned along their edges by screws into the upright (and horizontal) beams of 2 x 4 timber.

My box has a false floor. There is a hole in the centre that the speaker from the subwoofer fires downwards through into a bottom compartment with an open front. The bass sound waves then emerge from a slot across front of machine along lower edge, between the false floor the subwoofer is attached to, and the real floor of the box, located another 8cm or so beneath the false floor.

The subwoofer will vibrate so it has to be firmly attached to the wooden panel. I used thin underfloor insulation foam layer (with hole in) sandwiched between the subwoofer and the panel underneath it is attached to, so it would not make buzzing noises if the box vibrated against the wooden panel. I used a metal strip to make a clamp which holds the subwoofer firmly down against the deck, compressing the thin layer of foam.

Closer view of this subwoofer clamp mounting.

Subwoofer fires downwards into this cavity at base of cabinet, and bass emerges from front edge of this cavity.

Speaker is in base of the subwoofer and fires through a hole in the false floor it is attached to. Hole has to be bigger than the speaker cone of course.

The subwoofer box has a port in its rear. A hole is made in rear of marine ply enclosure that matches up with the port in rear of the black subwoofer box.

Smaller speakers mounted as shown so speaker cones are well separated and against sides of the main enclosure.

I glued them down with hot melt glue-gun and drilled holes in the false floor to allow long cable ties to be run around each speaker, holding each speaker box down firmly so their boxes will not "buzz" against the false floor if volume is turned up.

Front panel has a row of holes along bottom edge to let the bass from subwoofer flow out from the space beneath the false floor the subwoofer fires down into.

Also has holes that match the speaker cones of the small speakers each side.

Mesh is fixed with screws and washers along inside surface. This stops kids poking things through the holes to push in the centres of the speaker cones. Kids cannot resist pushing in the domed centres of loudspeaker cones I have found from personal experience!

I used cup washers and regular washers with short self tapping screws to firmly hold the mesh on. I perhaps overdid it but there is no way this mesh will be pushed off without a struggle.

I bought this LED lightshow from an electronics store. You can get them online too.

The modules stack in any arrangement you want a bit like Lego. The main thing is that they are low power LED based, they run from a low voltage wall adaptor, and so it does not generate any heat as light bulbs would do. This has to be thought about if you are putting them into a box.

A shelf is made inside the main box at the correct height so that the lightshow unit sits above the subwoofer without actually touching it.

A hole is cut out in this shelf so that the lightshow unit, assembled as shown, slots down into it, resting with the projecting outer top edges of the lightshow modules butting up to the top surface of the wooden shelf. This hole is a peculiar shape to cut, you have to mark it out (make a cardboard pattern first and test the fit with the lightshow unit), then patiently cut it out with an electric jigsaw. It does not have to be perfect, just good enough so that the lightshow unit does not just drop through your hole!

I mounted my shelf onto a length of 4x2 timber along underside of each outer edge just using a blob of blu-tack on underside of each corner to stop it vibrating. This means I can easily open top lid later on and lift it out if I want to change anything inside the main enclosure.

View from underside of lightshow unit.

Each module is connected with a plug in lead to the main controller module which is at one end of the assembly. You can see the hole I cut in the shelf with the jigsaw. Not elegant but good enough.

On the right of this view you can see an older iPod Touch. By the way this is my favourite Apple product of all time. It has the curved shiny back that Steve Jobs insisted upon to give the organic feel, like a flat pebble.

The computer speaker assembly will have a lead hanging out of it with a green headphone type plug on the end of it. This is meant to plug into headphone socket or audio-out socket of your computer. However, we are going to plug it into the headphone socket of the iPod.

Also, to stop the battery in the iPod running flat, we need to plug the iPod power lead into it too. The white thing plugged into the power bar on the back surface of the main enclosure is the power charger for the iPod.

The mains power bar at top rear of the main enclosure is there at top edge so we can easily reach it when top lid of enclosure is opened.

Mains power bar mounted simply to upper rear inner edge of main enclosure using big cable ties.

Into this is plugged:

a) Power unit for iPod Touch (the white thing).

b) Power lead for the computer speakers.

c) Power unit for the lightshow module.

You can see I have also used a hole cutter in a drill to cut a few smaller ventilation holes along upper rear surface of the main enclosure. Air will go in through speaker grilles, up through box and out through top rear of box.

The top lid hinges upwards, with hinge at rear.

We need to cut a big hole in it so the lights from the lightshow module can shine up through it.

As this hole is very visible, you need to make this hole neat.

I used a hole cutter tool in a drill to make the curved corners, and then a jigsaw to cut the 4 straight lines that interconnect the outer edges of each of these large corner holes.

The top lid is then varnished/stained and allowed to dry.

Here it is nearly finished.

Sturdy door hinges fitted along rear edge.

A rectangle of polycarbonate is cut to same dimensions of the top lid and then screwed to it all around the edges.

This makes the top surface more or less unbreakable no matter how hard you bash it or if you drop or spill things onto it.

I also fitted a latch to the front edge of the lid which is opened with a key, but self-closes. This was from a hardware store.

I fitted alloy angle section strips to the two front vertical corners and an alloy strip along the front that has a nice rounded downward curved front profile.

There is one extra hole in front of the right hand speaker in this picture. This is in front of the volume knob which is on the right speaker. I may make a plug in bung for this hole to cover it.

The subwoofer unit also has its own volume knob on it. If turned up to full, the bass will be too overpowering, therefore this will need some experimentation with, before you fit the upper shelf holding the lightshow modules.

Once these volume controls are roughly set, you can adjust the overall volume on a day to day basis, using the volume "slider" within the iPod music player app you are using.

For ultimate protection you can plug the (short) power lead into a low wall socket and then screw the whole machine to the wall with small L shaped brackets. This means that the power lead and wall socket is then fully covered also.