Usually I would take a break from intense studying by doing some non technical related activity such as cooking, baking etc. But in the office environment, en-suit kitchen is consider a luxury and way out of my reach. Instead, I make little toys (electronics) /handicraft (mastering the art of folding roses) to kill off the gloomy mood from studying non stop.
I wanted to make a Amplitude Modulated Laser Transmitter for Audio. There are many examples (successful ones) plastered all over the Internet.It originates from here ...
What you will need
1. 1x laser pointer S$1.9 from $2shop.
2. 4.5v battery
3. Audio output transformer (8ohm and 1k ohm impedance)S$1, S$3. This is the tricky one, i shall elaborate later.
5. Speaker, USB powered preferred over passive ones.
Connect them up accordingly. The schematics are available from the link above. From left the laser pointer, the battery pack, the audio output transformer and audio out from the laptop.
Now, hook up the receiver part. The USB powered speaker, LDR.
I guess there will be another round of parts hunting, AFTER I finish my exam.
During the 30minutes of playing with the above mentioned toy, i noticed something.
When I am holding the LDR+USB powered speaker's mini stereo jack on my RHS and the laser pointer + messy wires at my LHS. The speaker output some music even though I DID NOT press the "on" button on the laser pointer. Which it should not be the case. When I DID press the "on" button, the music is cut off! For a moment, I thought it is a very strange phenomena that doesn't make sense. But...after 2 seconds... HAHA.....
The first correct answer to that "strange" phenomena and why I press on the button of the laser pointer the music is off, shall get 1x muesli bar from me. Leave your answer on my post as a comment~
Nonetheless, it is still COOL to be the human conductor by touching both the receiver end and the transceiver end to produce some sound without using a physical wire. TRY IT AT YOUR OWN RISK!!! IF you or any parts thereof Got FRIED, I shall bear no liability nor responsibility.
Below is a video of it, still can WOW some crowd if it is packaged in a magic show. E.g, asking an audience come up to the stage to touch an exposed end (eg the receiver side), while holding at the magician's hand. The magician shall strut his/her stuff with the physics behind it.
now... back to the books..........