Have you ever wondered how we are able to send information across long distances to satellites or over oceans to other continents Laser communication systems encode information in the laser light by modulating its intensity. When the light hits the receiver, the changes in intensity are converted into an electrical signal and the information is recovered. The principle is used in Bluetooth, the internet, and cellphone communication.
In this activity, students will use the audio output from a cell phone, and transmit the signal via laser light to a solar cell receiver.
Converts digital electrical signal to laser light through amplitude modulation:
Accomplish amplitude modulation through a transformer:
Converts signal from laser light to digital electrical signal using a solar cell:
Jumper Wires
Twist-on Wire Connectors
Audio cable, 3.5mm, cut end: DigiKey P/N CA-2207
Audio transformer: Amazon, CynKen P/N EI14
Laser diode: Amazon, GeeBat P/N 80-141-10
Battery pack, AA, 3 cells: DigiKey P/N BH3AA-W
Jumper wires, female to female: Amazon SUNKEE 100pcs
Solar cell: Amazon 5V, 160mA 80x80mm
PVC pipe: McMASTER-CARR, P/N 4880K74
Audio cable, 3.5mm, cut end: DigiKey P/N CA-2207
Twist-on wire connectors, No. 22-14 gauge: Amazon 1,000pcs
Amplified speaker, example: RadioShack P/N 2771008