'GetUnderTheSkin' - Hacking and Making Sensory Toy Style Radio.

This document will show you how to make a 'GetUnderTheSkin' Radio that I designed as part of a University project.

We were given the task to redesign a radio using existing components from one we were given. I began by designing this around a character who would value this product. However, as my design and prototyping process unfolded, I recognised other uses and benefits the radio could have. 

It is a perfect sensory toy for those with special needs or visual impairments. It also allows you as the user to explore and develop your senses, using dial hands to feel your way to the volume and frequency you desire with bright lights pathing the way. 

It is a subtle focal point in any environment, bright lights and music grabbing your attention. It is designed to intrigue and bring out the curious side of the user, intuitively encouraging people to interact and engage with it.

The GetUnderTheSkin radio Can be seen as being a calming visual in a room, watch it glow as the daylight falls.


For this you will need :-

A circuit board from an old/unused radio. I used a Sony 2 band handheld radio.
2 sheets of plastic - 305 x 305 mm and 248 x 224 mm
High Density foam.
Stretchy Material (preferably Lycra, colour of your own preference) - 50 x 50 mm
Sheet of sponge material. (can use that of cleaning cloth)
20 LEDs (colour of your own preference, I used red but with clear plastic casing) and lots of wire for hooking these up. 
2 x AA Batteries 
Araldite Glue
UHU Glue

Tools :-

Soldering kit
Laser cutter
Hand sander

Step 1: Step 1 - Dismantling, De-soldering and Soldering.

The first thing that must be done is dismantling the old radio. This can be done with a set of screwdrivers and a strong hand! 

You need to de-soldering certain components to allow them to fit in the UnderTheSkin Radio. The tuner, volume and battery pack are the components that need de-soldered and extended a bit further. You'll see from the images just how far I extended them. 

I found referring to the 'Electronics for Dummies Cheat Sheet' and soldering tips on the internet was a good help. 

Step 2: Step 2 - Making the Base and Casing.

In order to make the base you must laser cut the sheet of plastic. This requires an illustrator file to be drawn. To save you the hassle - these are given below! 

Set the laser cutter to Speed - 10 and Power - 80 and then run it about 5 times. This cuts the plastic super accurately!  You can finish the plastic by flame polishing, this is optional. 

Fix the casing together. You'll notice that there is a door for getting into the batteries, use a small hinge (can be found in art and hardware stores) allow it to open and close. Araldite does the trick for cementing all this.

This is a good time to fit your tuner and volume dials in, then fix the cogs on with yes more Araldite..

Step 3: Step 3 - Wiring Up the LEDs.

I found it easiest to do play around with this first on a prototype model of the base (a piece of old card/kappa board will do), avoiding plastic laser cut base grubby. One of the main obstacles to get over was finding the right resistors for the LEDs to work. This is something I have never done before, therefore I got a great help from my lecturer. Here is the blog post he made following our efforts, I hope it is a good reference to you - http://zero-waste.blogspot.com/2011/11/finding-right-resistor-for-led.html

The LEDs have a positive long leg and negative shorter leg. 

Sit the 20 LEDs in the circles cut for them, placing the positive legs inward and the negative legs facing away from the base. 

Firstly, solder the negative legs altogether on each half (volume and tuning sides) . Then connect the two final ends of each half to the negative battery. 

Secondly, the positive legs are to be wired up through to the top side of the base. Strip the wire just enough that it is exposed on the top side, yet doesn't touch the other wire - prohibiting the LEDs from switching on individually.  It is also important that the stripped wires are nice and straight, to allow a smooth interaction between it and the resistors in the dials (I will take you through making these in the following steps). 

Finally, solder 2 x  27 ohms resistor to 2 long wires, one for each dial. Hook them through central holes of plastic base and then solder these to the positive side of the battery. 

You should find that when you touch the resistors to the smooth wire your LED will glow! 

Now that is done, you can glue the LEDs into place Araldite glue is the best for this.  

Step 4: Step 4 - Making the Dials.

It is essential for this design that the dials are nice and smooth. I found that the best material for this is to use High Density Foam sculpted into shape. I used a hand sander and some sand paper to get a good finish. This takes a lot of time to make sure the two are even but worth it in the end for the perfect interaction! Using a drill, lightly indent a hole on the underside of the thick part of the dial - this is for the tuning/volume cogs to be inserted into.

Once the dials are nice and even, give them a couple of coats of white spray paint.

Now for the tricky bit. Take the long wire with the resistor and line it up centrally on the underside of the dial and glue it (I found UHU to  be the best for this). Again, make sure that this is nice and straight for a smooth result. 

Finally, cut a thin sheet of foam, or smooth material to the same shape as the underside of the dial (remembering to leave a hole for the cogs and a slit for the resistor to poke through) and stick it down using UHU. 

Ensure that when you place the dials over the volume/tuner that the resistor and wiring on the base meet and glide over each other. Once this is nice and smooth, glue the cogs to the dials using Araldite. 

Step 5: Step 5 - Making the Slip Cover.

The material I found looked best for the GUTS radio is Lycra. I thought this because it is stretchy and thin enough to get a good glow from the LEDs through it. Although you can use whatever material you like, of any colour or texture. 

This is a simple sewing procedure. I found it easiest to make a card  circular template, 20mm in diameter wider that the 300mm circular base. (I made this template using a Wok of all things as a guide! Anything large and circular will do!)

Pin the template to the material and simply cut round, leaving you with a perfect circular shape. Fold in the material round the perimeter and pin it. Then stitch this together using a sewing machine - leaving a slit for you to put the elastic through. This stitching is to allow a kind of pouch for the elastic (acting like a waistband would). Work the elastic through the pouch you made, ensuring you don't lose the ends. A handy trick to avoid this is attaching a safety pin to the end of the elastic. Once you've worked it through the perimeter pouching of the slip cover, tie the two ends with a neat knot and sew up the slit. It should look a bit like a shower cap when its made!

There you have it , a slip cover for your radio. I made one in black and one in white.

Step 6: Step 6 - the Final Touches.

The last efforts are the messiest - involving lots of glue! 

Using Araldite, glue the tuner and volume components into the base if you haven't done so already. (shown in previous images - step 3)

As you can see from the images I made stoppers, to avoid the dials touching and causing a short circuit. These fit into the holes given and are 10 x 20mm (these available are on the casing pdf. ). Glue these into place with Araldite.

Use a thin foam material to cover over the wiring of the LEDs and make the backing more presentable. It is also a good surface for the slip cover to cling to. Simply trace round the radio base and and measure out the casing to cut it out. I stuck this down with UHU and it worked perfectly. 

I have uploaded my hand drawn exploded view, this should help you when figuring out what goes where! 

Step 7: Finit.

Now step back and watch your 'GetUnderTheSkin' radio glow. Notice the change in brightness as the daylight falls!  

I hope this has been a good step by step account on how to hack a radio and build your own 'GUTS'. It would be great if you could take the time to let me know what you think of this document and give it a rating!

Lynsey Brownlow.