The Black World Of Solitude.

Saturday, 3 April 2010

Done!

Finally, after a few hours, I'm done with my own blogskin.

Actually, it isn't my own. Rather, I edited a current one very drastically such that it looks completely different from the original. Still, I left the credits there. The picture was taken in Malacca during my Overseas Education Programme, and I uploaded it on imageshack for the picture to show up. The link under the credits should show you the author.

=D

Yesterday was a weird day. My friends and I had to do an electronics project, and so we sent to Sim Lim Square to buy the solid-state electronics (transistors and all those crap). We ran around in circles trying to look for a suitable shop until a kind soul told us that we could find what we're looking for at Sim Lim TOWER.

Damn, all the trouble. We went across the streets to access the tower, and bought the parts. Bought the wrong thing (I mistaken the positive and negative voltage regulator for a transistor) and we forgot to buy resistors with the proper values (we needed 3.6 megaOhm; we bought a 2.2 ohm one). We needed a capacitor as well, but we didn't buy it.

So when we went to one of my friend's house to assemble the parts, we were stuck. We bought piezoelectric transducers to convert sound waves to electricity, though there must be a coupler (like a cone) to make the piezoelectric transducers react to sound, otherwise they can only detect vibrations. So we were doomed, because it means that my plan has failed.

Anyway, the plan was to have a mini microphone that takes in sound from the surroundings and sends it to a vibrator. This vibrator will alert people of sudden loud sounds (normally indicating imminent danger) through vibration, and this vibrator is attached to the skin. So loud sounds will make the vibrator vibrate like mad, while ambient sounds would still make the thing vibrate, albeit of a lower intensity. To prevent any vibrations at all for ambient sounds, a resistor can be added to attenuate the signal received.

My 2nd design consists of a piezoelectric microphone that is attached to a piezoelectric speaker (all speakers vibrate to create sound, just attach that cone to you and you will feel the vibration). However, piezoelectric microphones have high impedance, and for some reason which might be due to the circuit itself being of low impedance, no current was generated when I smashed the piezoelectric disc. And the speaker needs alternating current between 4 to 7 kHz otherwise a sine-wave generator must be connected. And the crystals do not vibrate with great intensity. So ultimately, piezoelectrics cannot be used -.-

My original design consists of a dynamic microphone that is attached to a dynamic speaker (the normal ones you have at home). But they were large and bulky, therefore I went with the piezo, but then it did not work.
I could have used a headset that has microphones in it and extract them (obviously they are tiny; you wouldn't want to attach them to your body if they were the size of the ones people use on stages). We could extract the stuff from a telephone too, just remove the duplex coil and they will work. Since the dynamic mic and speaker are of low impedance, the circuit needn't contain high value resistors.

And finally, my third design shall be used if the speaker fails to get anyone's attention. Instead of a vibration, heat can be used to alert the person, but that's a different story altogether.

And what about those piezos my friends and I bought? I'll just use them for my amplifier ^_^

Labels: Mohenjo-Daro

人之命，若无意，何生乎？10:25