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laser_transceiver [2014/11/11 13:30]
cwh0009 created
laser_transceiver [2014/11/11 15:34] (current)
cwh0009 [Experiments/Demonstrations]
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 ====== Overview ====== ====== Overview ======
-The laser transceiver is a free space optical communication device that encodes audio on a laser beam using pulse width modulation (PWM). A single transmitter and receiver unit can be built for about $15-$20 in parts. We used to use this for a demonstration in ELEC 3030 (RF Systems Lab), but aligning the lasers took quite a bit of time to setup.+{{:​transmitter_1.jpg?​direct&​200 |}}The laser transceiver is a free space optical communication device that encodes audio on a laser beam using pulse width modulation (PWM). A single transmitter and receiver unit can be built for about $15-$20 in parts. We used to use this for a demonstration in ELEC 3030 (RF Systems Lab), but aligning the lasers took quite a bit of time to setup.
  
 ====== Design ======= ====== Design =======
-This uses a laser pointer communicator designed by Ron Jones (K7RJ). We made no changes to it. +This uses a laser pointer communicator designed by Ron Jones (K7RJ). We made no changes to it other than adding an on/off switch
- +  * [[http://​ka7oei.blogspot.com/​2012/​09/​voice-on-laser-beam.html|Blog post with K7RJ's laser transceiver]] 
-====== ​Bill of Materials ======+====== Materials ​List ======
 Here's a list of the stuff you'll need to buy to build one. It runs off two 9V batteries, so you'll need to buy parts that are rated above 9V. Stuff in the 15V-20V range is good, but if you can find stuff for cheap that's rated higher than thats fine. The diodes we used were rated to 100V and the electrolytic capacitor was rated to 35V. Here's a list of the stuff you'll need to buy to build one. It runs off two 9V batteries, so you'll need to buy parts that are rated above 9V. Stuff in the 15V-20V range is good, but if you can find stuff for cheap that's rated higher than thats fine. The diodes we used were rated to 100V and the electrolytic capacitor was rated to 35V.
  
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 ^ Item                                   ^ Quantity ^ Manufacturer Part Number ^ ^ Item                                   ^ Quantity ^ Manufacturer Part Number ^
-| photo diode sensitive to 650nm         | 1        | | +| photo diode sensitive to 650nm         | 1        | SFH 229                  ​
-| 100k ohm resistor ​                     | 1        | | +| 100k ohm resistor ​                     | 1        |                          
-| 0.01 uF ceramic capacitor ​             | 1        | | +| 0.01 uF ceramic capacitor ​             | 1        |                          
-| 0.1 uF ceramic capacitor ​              | 2        | | +| 0.1 uF ceramic capacitor ​              | 2        |                          
-| 10 uF electrolytic capacitor ​          | 2        | | +| 10 uF electrolytic capacitor ​          | 2        |                          
-| LM386 opamp                            | 1        | | +| LM386 opamp                            | 1        | LM386N-1/​NOPB ​           ​
-| 3.5mm audio jack                       | 2        | | +| 3.5mm audio jack                       | 2        | ACJS-MV35-3 ​             ​
-| 1N914 diode                            | 1        | | +| 1N914 diode                            | 1        |                          
-| 0.001 uF ceramic capacitor ​            | 1        | | +| 0.001 uF ceramic capacitor ​            | 1        |                          
-| 100k ohm resistor ​                     | 2        | | +| 100k ohm resistor ​                     | 2        |                          
-| 15k ohm resistor ​                      | 4        | | +| 15k ohm resistor ​                      | 4        |                          
-| 240 ohm resistor ​                      | 1        | | +| 240 ohm resistor ​                      | 1        |                          
-| 4V zener diode                         | 1        | | +| 4V zener diode                         | 1        | TZX3V9C-TAP ​             ​
-| LM311 opamp                            | 1        | | +| LM311 opamp                            | 1        | LM311N ​                  
-| 741 opamp                              | 1        | | +| 741 opamp                              | 1        | LM741CN/​NOPB ​            
-7555 555 timer (CMOS 555 rated to 15V| 1        | | +| 555 timer rated to at least 15V        | 1        | NE555N ​                  
-| prototyping board                      | 2        | | +| prototyping board                      | 2        |                          
-| red laser                              | 1        | | +| red laser                              | 1        |                          
-| 10k ohm potentiomter ​                  | 1        | | +| 10k ohm potentiomter ​                  | 1        |                          
-| 9V battery clip                        | 2        | | +| 9V battery clip                        | 2        |                          
-| SPST switch ​                           | 2        | |+| SPST switch ​                           | 2        |                          | 
 + 
 +===== Other Materials ===== 
 +You will also need: 
 +  * A microphone 
 +  * Speakers 
 +  * Cables to connect the microphone and speakers 
 +  * Two 9V batteries 
 + 
 +====== Photos ====== 
 +===== Transmitter ===== 
 +{{:​transmitter_2.jpg?​direct&​400|}} {{:​transmitter_4.jpg?​direct&​400|}} 
 + 
 +===== Receiver ===== 
 +{{:​transmitter_5.jpg?​direct&​400|}} {{:​transmitter_3.jpg?​direct&​400|}} 
 +====== Experiments/​Demonstrations ====== 
 +  * Place a fan in between the transmitter and receiver, breaking the laser. The fan will generate a tone as it spins. 
 +  * Use the receiver to listen to light and see if anything else generates sound. Fluorescent lights should. 
 +  * Shake power or dust through the laser, or transmit through a stream of water. It should interrupt the audio.
laser_transceiver.1415734246.txt.gz · Last modified: 2014/11/11 13:30 by cwh0009