So there I was, sitting around, when I deiced to do something. I hit the lab, and using some random parts sitting around the place, I was able to construct a crude (but working!) Mechanical TV!
Some pics (sorry bout the poor quality, my camera is a peice of junk, LITERALLY
)Here's a Pic: http://www.imageigloo.com/viewer.php?id ... %20001.jpg
Another view of it: http://www.imageigloo.com/viewer.php?id ... %20003.jpg
Closeup of the LED Assembly: http://www.imageigloo.com/viewer.php?id ... %20007.jpg
Here's and Overhead View: http://www.imageigloo.com/viewer.php?id ... 20002x.JPG
The operation is really simple, the spinning disk (known as a Nipkow disk) has holes in it, holes that go around the disk, and spiral inward about a half inch before stopping. These holes create the scan lines for the unit. The LED below it, provides the light. It creates a picture by taking various pulses of light energy, and when combined with the spining of the disk, is able to create a low-resolution picture.
This particular system of transmitting moving pics was patented way back in the mid 1880s (WOH! TV was around back THEN!?
) The design had two key flaws though. 1.) It required a lot of light to work.
2.) Even with a lot of light, it could only send the single on wire a short distance. As there were no radios or electrical amplifiers back then.
It wasn't until the early 1920s that electronics had caught up enough for a radio device and a signal booster be created, allowing for true television broadcasting. A lot of this work was pioneerd by a british fellow named John Logie Baird. He developed the first practical Televisor broadcasting and receiving equipment. He also developed a system he called "Phonovision". Which was really cool stuff -- Because the light pulses were of such a low frequency, they were acutally audible! (as in, you can hear them) and since they were audible, he came up with a method of storing the video information on a RECORD! Pretty cool!
Since the video can be stored as audio, I found a place where could downloaded a couple of test screen tracks. These tracks are REALLY annoying to listen to, but when the signal is played across the LED circuit, it makes the light flicker. When the wheel is spun at the right speed, you can make out a picture!
Pic of the wheel spinning: http://www.imageigloo.com/viewer.php?id ... %20009.jpg
Another pic of the spinning: http://www.imageigloo.com/viewer.php?id ... %20011.jpg
I'd have an image of the tv picture, but it can only be seen in the dark (LED isn't very bright), and my camera can't take pictures in the dark (any extra light would drown out the weak picture--so no flash = no picture
).The resolution of my "televisor" is about 32 lines at about 12.5 fps. In contrast, the first Tube-based TVs that followed this machine in the mid to late 30s were 405 lines at about 20 fps.
It's pretty interesting to see how things looked nearly a century ago. Look it up! There's a lot of intersting info out there, even a radio station that broadcasts 32 line Television (you gotta build your own reciever)!
I'm gonna try to build a better one in the future. One that uses a Metallic(a) disk with precisly drilled holes, and a way brighter light. As well as a device that can automatically sync the motor speed with the picture. Somewere along the line, I'm also gonna try to make a Camera, so I can send and recieve my own 32 line (or better) television!
its totally awesome and im amazed that things like this were possible in the 1880s
