The general concept of my radio is that the battery pack is taken out of the radio casing into an external, removable key that when inserted into the open top of the new body, connects up the circuit and turns it on. After this, when the key insert is twisted, it controls the volume of the radio. The idea behind this was to make it easier for an old aged user to interact with the radio without small inconvenient and unnecessary buttons.
Here is a link to a short demonstration video of the final prototype.
Step 1: Radio Overview
The radio is cuboidal, measuring around 750mm wide x 1200mm high x 250mm deep. To dismantle the radio I first removed all the external screws. Then, with a flat screw driver and knife, gently went around the centre divide slowly prising the casing open, being careful not to damage any of the internal components. The radio circuit board is held down with two small clips that when pulled back loosens the parts allowing the circuit board to be taken out from the case. The small speaker cone was glued to the inside of the front casing, later on to get it out I slightly cut through the glue and pushed though it popping it out with out any damage.
Step 2: Initial Electronics
Step 3: Building the Outer Housing
The large cylindrical base of the radio was made out of two thick 15mm thick MDF rings with an external diameter of 180mm and an internal of 140mm. Above and below were two 5mm thick MDF circles of 180mm diameter.
The base has a 55mm diameter hole drilled centrally to house the speaker cone which was later finely sanded to fit well and glued gunned in.
The top has a 60mm hole centrally so that the electronics from below can be wired up through the middle housing. On the left hand side of the top cover there is a 10mm hole for my fm/a, toggle switch (however this may vary depending on what switch is used), a 5mm on the right for the ariel to be thread through from underneath and a 23mm hole centred at the front. The position of this will vary depending on where the circuit board below is actually positioned.
To position the circuit board I cut into on side of the base housing. I had to spend a while measuring it accurately so that i could position the tuning dial in the right place externally as the tuning dial has not been taken for the board.
Step 4: The Upper Housing
Step 5: The Key Insert Body
Using 12mm MDF again, following the same format as the other parts of the casing cut 4 x 60mm circles, 3 with a hollowed 40mm inner diameter and one left whole.
For the top half cut 3 x 100mm cylinders , 2 with a hollowed 80mm inner diameter and 1 with a 40mm inner diameter.
To make the battery pack accessible screw a 100mm diameter circle, on 2mm MDF, to the top. This is ideal as it does not add extra unnecessary wood to the key but will conceal the inner batteries and wires.
For the bottom section I designed an extruded 'plus' to insert inside an identical hollowed cut out, kept within the radio. When they are placed within one and other they connect the battery wires to the wires coming from the under body via flat conductive metal pads. The plus has two long narrower opposite lengths and two opposite shorter and wider lengths. The reason for this design was to create a groove that would catch when inserted turning the mechanism below but also eliminating the 50/50 chance of the positives and negatives touching the right pads if the plus had been perfectly symmetrical. Instead the longer sides deal with the positive wires and the shorter with the negative wires, that have been forked from the single battery wires.
The dimensions of this 'plus' are in the final photo. The hollowed part has to be slightly larger than its insert so it fits smoothly, do this by careful sanding to get the perfect fit.
Drill four 2mm holes, one through each edge from inside the key to the base, so that the wires can be threaded through in the next stage.
Step 6: Key Electronics
Step 7: Key Internal Inset
For this i followed the same process as before sticking the pads inside the grooves and drilling out the sides from the brass.
This was all mounted on a small 60mm circle of 2mm MDF to be more easily attached to the top of the volume component.
Step 8: Volume Component Housing
Step 9: Key to Volume Conversion
Step 10: Finishing Elements
Wire up the ariel and fm/am switch pushing them through the pre cut holes, which hold them tightly in place.
Add sticky pads to the underside of the radio to raise the speaker from the ground stopping damage and boosting the acoustics of the radio.