Timing Devices Essay, Research Paper

The construction of the timing device was very simpleThe circuit was constructed,

as any other circuit would be involving a lot of minuet

soldering. However there was a size limit that I had to work to. The circuit

itself with all the components including a nine-volt battery had to fit into

the waterproof box earlier acquired. This meant that the PCB for the circuit

was created in the shape of the box to give maximal room for the components. I

firstly photocopied the layout of the box and then created the PCB based on

this shape. However the box only measured a height of 25mm, length of 55mm and

width of 48mm. This created the problem of running the tracks of the PCB very

closely together resulting in the breaking of them the first time around.

However a second attempt and a lot of effort later resulted in a successful

circuit.The first problem I had with the box was that the mounting

heads and inner walls in the box had to be removed to create as large an area

inside as possible. With this done I then had to drill holes of the appropriate

size and placing for the LED?s and two switches.With the circuit completed the components were all sealed

in their places and the last thing to do before the box could be closed was to

interface the stopwatch. This was a very detailed job. On the opening of the

stopwatch I found that there were two connecters upon where I needed to solder

the wires. They were the original connectors for the activation of the

stopwatch and needed bending back and exposing before they could be soldered.

However this was done and so the wires were slid down the plastic tubing and

into the electronic box.The box was finally closed and screwed down tight into its

waterproof seal by four extra long screws that were part of the mounting design.

With the screws exposed I cut out two cross beams measuring; 52mm by 100mm by

1mm. These crossbars then helped install the box to the chosen position behind

the brake lever under the handlebars. It was Held in place by some wing nuts,

which help in the removal and adjustment of the whole fitting. The watch was

last to find its way onto the handlebars having only to be attached like it

would on that of a wrist.?