High School Engineering Competition
Christian Brothers University
3:30 PM on April 14, 2011
Sponsored by the IEEE Student Branch
Crystal Radio
A crystal radio receiver is a very simple radio receiver, popular in the early days of radio. It needs no battery or power source and runs on the power received from radio waves by a long wire antenna. It gets its name from its most important component, known as a crystal detector, now called a diode. (http://en.wikipedia.org/wiki/Crystal_radio)
The Department of Electrical and Computer Engineering challenges you to design, construct and assemble a “crystal radio” using a diode, piezoelectric (ceramic) earphone, cardboard, toilet paper tubes, aluminum foil, glue, tape, metal thumbtacks, wire, coke can and paper.
Rules
1. The only materials that can be used to construct the crystal radio are as follows:
• One germanium diode - 1N34A (D1)
• Piezoelectric (ceramic) earphone (E1)
• Cardboard and paper
• Toilet paper tubes and round Quaker Oats container
• Aluminum foil
• Glue
• Tape – scotch, electrical, or masking
• Metal thumbtacks, alligator clips or fahnestock clips
• Wire – insulated or magnetic of 20 to 30 gauge
• Coke can
• One wooden board of a thickness of less than 0.80 inches
• S1, L1, C1 and C2 will be constructed using the items listed above
2. An electrical ground will be provided by CBU.
3. An antenna will be provided by CBU with a length of 50 feet to 100 feet.
4. The radio must be designed so that connections can be made for the electrical ground and antennae with alligator clips that will be supplied by CBU.
5. The crystal radio project, not including the ground and antennae provided by CBU, must fit in a 30 cm by 30 cm by 30 cm box. The project must be designed so that the earphone and C2 are connected with thumbtacks, alligator clips or fahnestock clips.
6. The design of each radio must show significant contribution by the contestant.
7. The crystal radio must be capable of receiving radio broadcast in the frequency range of from 540 kHz to 1600 kHz.
8. A winner will be declared based on the power output to the earphones of the crystal radio at particular frequency to be provided at the competition. The contestants can determine the power output by tuning the radio using the coil and capacitors for maximum volume.
9. Answering questions, interpreting rules, settling unexpected problems and making the final decision rests with the judging panel.
