Our goal was to design do-it-yourself science equipment for use in a science lab at Kepler University in Rwanda. We decided to make lasers using the red lasers from a DVD burner. The students at Kepler could make them, and then do experiments with the speed of light, as well as wavelengths of light. In the end we used purple lasers from MIT, but the students at Kepler may be using the DVD lasers instead.
The circuit for our laser pointer took up most of the time in the two week period. In order to use a laser, one needs to create a driver circuit to ensure that the lasers receives a constant current and voltage. We used a solderless breadboard and a potentiometer to start, but soon realized that a resistor and solder breadboard could be used instead. Our final circuit is soldered to a small breadboard and velcroed to the project enclosure. The circuit provides a constant voltage and amperage, giving the laser just enough power for it to light up. Because the circuit and battery do not provide that much power, out laser is not very bright but that could easily be fixed if we had more time.
The enclosure was originally thought to be a sheet metal box. We realized that it would be hard to make that, so we decided on using a project enclosure from Radioshack. The box is composed of a plastic box and lid, with an aluminium plate on top. There is a hole drilled into the front for the laser diode to go through, as well as a slot for the switch. Our enclosure makes the laser pointer into a perfectly sized handheld device that can be easily opened for repairs, and battery replacements. The electronics are attached to the box using velcro, making them easily removable. While this box helps to make the laser complete, there are some problems with it. The main part of the project box is thin plastic, making the whole product feel cheap and slightly flimsy. Because the box is so small, we also had a hard time getting the electronics to fit in it. Now the electronics are in the box, but the wires are bent in weird ways in order to fit that could result in a short circuit. If we had more time we would work on making a new box from scratch, but for now this works pretty well.
Our final product is a laser pointer enclosed in a modified project box. There is toggle switch located on the left side which turns the laser pointer on and off, and the laser beam comes out of the front. The enclosure is a project box from Radioshack with holes in it. The box is composed of a plastic box and lid, with an aluminium plate on top. Our final laser pointer is creates purple light, but it is not very strong. Because of this we would have tried to make a red laser pointer so that we would have a more intense laser pointer if we had more time. All in all our final laser pointer is great for the amount of time we had to work on it, but it could be better.