A laser audio transmitter is a useful project for students to introduce themselves to the fundamentals of electronic design. The goal of the project is to transmit analog audio signal over the beam of a laser pointer into a receiver, which in this case is a small photovoltaic cell. Since this is an introductory level project, take the time to explain all necessary materials and assembly processes to the students. The parts required for this project are a laser pointer, a small solar cell, a battery power pack with room for three AA batteries in series, an audio output transformer, a small amplifier, and a radio, as well as some inexpensive earphones that you can salvage audio wire and jacks from. The total power supply should provide for a half volt of electricity. You'll also need two jumper cables to connect the laser pointer to the rest of the circuit. Next create an in-line connection from the audio output transformer to the laser pointer's power supply. It can be helpful to create a quick reference diagram for your students. Attach an input cable to the audio amplifier and the stripped ends of the cable to the solar cell. This will allow the device to receive a basic analog signal. The audio input on the sending end of the device can use a microphone or portable music player, attached with the audio jacks.
Building on the principles of the aforementioned project, a laser data transmitter takes the complexity one step further; instead of simply transmitting analog audio data, students will need to either devise a complex array of lasers to take the place of each cable in a wired connection, or they will need to devise a software-based solution for turning a single laser apparatus into an appropriate digital data transfer device. This activity can be supported by locating diagrams of standards relating to ethernet cabling for the students, which will be one of the easier to complete methods of data transmission. Students will have to contend with laser arrays per transmission and will also have to consider the fact that a signal needs to travel in both directions, meaning a receiver and transmitter on each computer. Rather than outline the exact materials and steps required, organize students into groups and allow them to brainstorm their own approach to the problem. Encourage them to ask questions when necessary and allow the most successful group to demonstrate their design to the class.
Once students have successfully completed an intermediate level project such as that of a laser data transmitter, they will be well-equipped to choose from a series of advanced level projects. Advanced level projects often require a greater level of circuit board understanding, which will require supporting textbook study. A possible project for advanced level students is building their own functional USB card. Individual students and student groups who were able to complete a functional USB card can compete to see who can store the most data while operating at a relatively low fixed budget. Other students may wish to experiment with Bluetooth technology, which simply put, is short range radio communication. Students with an aptitude for optical technology may wish to consider a project in network control lighting devices or even optical 3-D scanning. A more challenging project available at the advanced level is that of mechanized home control. Costs can be prohibitive for obvious reasons; however, this may present a very challenging project for the entire class to confront as a whole. Rather than use a full-sized house for the project, consider limiting the space used to that of a few conjoined garden sheds which can then be used by the school, auctioned off or disassembled and saved for next year's class.