Of course, lots of fun in electronics comes from other types of componets- light dependent resistors, magnetically activated reed relays, potentiometers, rotary encoders, pushbuttons, dip switches, and many others. We created a couple of those components for various circuits- we have some ideas for others. Below find some pictures and details of things related to these other components.
 |  |
The photoresistor is a good example of just how quickly, easily, and cheaply a component can be made. This one was made out of three styrofoam plates fished out of the trash in the 10 minutes before people started showing up at our Minne-faire. It's not perfect but it is a fairly accurate representation of the component, and it WORKS! | Unpainted dip switch bank. As the switches slide back and forth, copper foil on the underside of the top plate connects with foil on the switch, making the connection. Jon and Karin put this together in perhaps an hour with scrap wood and cardboard from around the shop. |
 |  |
A nice view of the switches before they went under the cover plate. The copper foil on the crossbar of the "T" is clearly visible. Aluminum foil or cut up cans would be probable substitutes; we happened to have the copper foil on hand. | Pushbutton made by team members Jon and Karin. This one is charming in its simplicity as well- it's a cardboard box and a condiment cup. They get bonus points for reusing a box from Sparkfun! |
 |  |
The innards of the pushbutton. The wires are pressed against copper foil; steel wool forms a fairly compliant contact. The spring force comes from some coiled solid core wire and the bridging contact is more copper foil folded around the rim of the cup. | Rotary encoder in process. The shaft is a piece of the plastic tubing we used elsewhere for capacitor bodies; the end plugs are foam core that has been hotglued in. The shaft of the encoder is hotglued in as well. This will be placed in a box in much the same fashion as the pushbutton. |
I will update this post if additional parts are completed in time- however, I think this shows a nice cross-section of what can be done cheaply and easily.
A few other things that might be fun to implement:
- 7 segment display
- buzzers (we do have a buzzer but it's fairly small)
- relays (a large homebrew that allows students to see how the switching mechanism works would be particularly appropriate)
- potentiometers (similar to the rotary encoder; may be a bit harder owing to the added torque that can be placed on it when it hits the limit)
- large toggle switches or push buttons (NKK SmartSwitches would be fun but expensive to use here)