The biggest problem with this radio is that it appears that the battery only lasts a few weeks and they cost R 25.00 a battery… the radio was only about R 45.00 (it didn’t come with a battery though). The conspiracy theorists in me says the reason it goes through batteries so quickly is because its made (or at least branded by) a battery company.

Battery

Yesterday the battery started to die and the wife wanted me to buy another battery for it… Thats when I had a light bulb moment (to quote Oprah) and decided instead of buying another battery I would hack the radio to run off the mains power.

I got approval from the Wife for this project, although it couldn’t cost more than the battery or a new radio.

Multi Voltage "Wall wart"

So yesterday after work I went in search of one of those “wallwart” multi voltage power supplies, the only one I could find at the local mall was a fancy switch mode power supply that put out up to 2.5amps but it cost R 199 a little over budget. A visit later to my in-laws saved the day when my father-in-law found a box of the little wallwart’s in the garage that he inherited, I grabbed a few in case one of them didn’t work and took it home.

I scratched through my parts bins and found a DC jack that the wallwart’s plug fitted and a few bits of wire and I was ready.

First job was undo all the screws on the radio and get it open, once open I quickly traced all the wires and worked out where on the board they all go. The plan was to wire the jack in so that when the plug was in it would disconnect the battery and run off the wallwart but when you remove it, it’ll work off the battery again. 20 minutes of soldering, cutting, wire stripping and fiddling with various screws and it was done.

I double and tripled checked everything with my multi-meter so that I didn’t blow anything up when I plugged it in, stood back and switched it on… and didn’t let out the magic smoke. After the successful switch on, I drilled a hole in the back to mount the jack, routed all the wires round the board and put it all back together.

Don’t worry my wife hardly ever reads this site so I doubt she’ll read all this and anyway she’s unlikely to puzzle out what I’m up too, but because I don’t want her to know what I’m building I’m going to stick to describing the technology and tools I’m using and show snippets of code but try not give it all away.

Without giving too much away about the project, I’m busy re-purposing things and trying to squash them into a new housing. One of the bigger problems is trying to do this without my wife finding out what I’m up to, so I can’t unpack everything and spread it all out on the dining room table.

I’ve decided to modify a store bought item to be the casing for the project mainly this is because the project is going to be displayed in the lounge and I’m not sure if my wood working skills are good enough to ensure it looks good.

I’ve been doing all my design and test fitting on my laptop using a free tool from Google called Sketch-Up, its an easy to use 3D design program. The cool thing about Sketch-Up is that it does things in millimeters (or other units of measure) so its easy to transfer measurements from the real world into the 3d one. I recreated all the components whose sizes can’t be changed in Sketch-Up and then did test fits of the items to see if they fit correctly.

Sketch-Up has allowed me to virtually build the entire present and solve many problems that I had not originally foreseen without the Wife finding out or it costing me anything in lost time or materials. Once I’ve designed and worked out what the individual parts are going to look like and how big they’re going to be it just requires a quick trip down to the shops to buy the items and then a few days of cutting, sanding,  painting and soldering.

I’ve also been using Sketch-Up to design furniture for our flat, the biggest problem is that a lot of store bought furniture is very badly made and rather expensive and its never just the right size for a room if you live in a small flat. On the right you can see a 3D diagram of a desk that I’ve been working on for the 2nd bedroom.

Sketch-Up can also be used to do 3D buildings and once you’ve built the building you can pull it into Google Earth to see what it’ll look like in the real world.

Sketch-Up is a very nice, relatively simple and easy to use application. There is a basic free version, which is what I’ve been using although you can upgrade to rather fancy pro version if you need too.