In my GCSE Major project for DT electronic products, I wasn’t pleased with my circuit, as however many times I tested it, it wouldn’t work. However, I think the rest of my project went well. The first thing I did was design my circuit by computer. I based it on one published in Everyday Practical Electronics Magazine, although I made some alterations to it to suit my specifications. This was then etched in copper onto my printed circuit board. Next to be added were the components. After going down to Maplins to buy what I needed, I drilled holes in my PCB and soldered them in. This was one area where I had problems because sometimes as soon as the solder dried I noticed it hadn‚t stuck onto the PCB and I had to do it again. Needless to say, it took me a lengthy period of time to solder every component.
The casing wasn‚t as tricky for me to make. Two of the boxes I made were for two separate teams in a pub quiz and both contained just a large push-button. The main box was designed for the referee of the game to monitor who answered the questions first and consisted of the main circuit, an on/off switch, and a reset switch. To make the main box I took five pieces of acrylic and sawed them to the right size. Mr. Heather glued them together. Next lesson when the glue was set, I took another piece of acrylic and bent it with a strip heater to make a lid. Also, I had to spend a lesson sanding the corners down. Something that went wrong during the making of my box happened when I was drilling holes for the switches. While I was drilling, the plastic snapped in half and flew off the clamp. I prevented this from happening the second time by drilling slower.
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The two push-button cases were made out of MDF, which I glued, sanded, and painted black to match the other box. Making the casing was one thing in my project that went well, and I think they looked professional and attractive. It was durable and light as I had put on my specification. While I was making my product, I made some adjustments to my original idea. The first change from what I had intended was the push-button I used. The one I used was small compared to the ones I described on the research page; this was because there weren‚t any bigger ones in stock at any local component shops. I changed my box design to accommodate them and drilled the right size holes, so the push-buttons turned out fine.
The second adjustment came when I had planned to use signal lamps to show when each contestant pressed their button, but the wires broke on them, so I had to use some LED‚s. These were the best thing in the stock cupboard I could find to fit my casing. This was because I didn‚t have time to buy any more components; the circuit was to be handed in the next day. If I did it again, I would improve the quiz boxes by getting more quality components as one of the reasons why my circuit didn‚t work could have been my components weren‚t the right values or were broken. I would also redesign my circuit board – it could have been made smaller, and also I did the space for the thyristors wrong and one part of my track was unused.
Another improvement would be to use less wiring on my components. Some of the wires were too long, and they always got tangled up. If my quiz boxes were to be produced industrially, I would have cut down the wiring, as useless wiring would be a waste of materials. Making a prototype for an electronic product was tough and very time-consuming. I had to stay behind after school a few times to finish the soldering and testing. Although I didn‚t get my idea to work as I had planned, I did learn a lot about circuit design and I gained experience in making and designing electronic products.