mid-term project

So, for my mid term project, I took this 1970's (???) portable television set...

...and added variable resistors to the electromagnetic yoke-controls.  TV yokes determine the positioning of the image on the screen.  The modifications limited the yoke positioning signals for the horizontal and vertical positioning, I crossed the x--y axis controls (creating circular and semi-3D imaging).  I also connected one of the yolk input voltages to the TV's  audio amplifier input, I then connected the audio output to the video input on the device.  Here is the initial modification: 

I wanted to automate these controls somehow, so I decided to cut gears out of wood and attach them to the pots like control knobs.  I printed the gear outlines off of this website:

http://woodgears.ca/gear_cutting/template.html

...which is a great site!  You can test different gear settings, then animate them to approximate the transference of degree of turn.  I had to change the 180 degree turn of a servo motor to (approximately) a 270 degree turn of the potentiometers.  After printing the gear outlines, I glued them onto wood, and cut them out using a band saw, as well as a scroll saw.

here is a video of the first test...  two gears = one motorized and one attached to a pot:

this seemed to work just fine, so I printed and cut out two more pot-gears and wired it up.

at this point, the modified TV had inexplicably changed.  Im pretty sure I accidentally fried a diode, or resistor somewhere within the circuitry from over use.  But no matter, it still worked, only differently... and actually for the better!

Because the TV's parameters had changed, I had to adjust my project accordingly.  I decided to have my gear box not only automate images on the portable TV, but also automate parameters of the video-noise generator I had built over christmas break.

I first finished building the gear box, then figured out what parameters I wanted automated for the noise-generator, and which parameters I wanted to leave manually controllable.

pictures of the nearly completed gear box:

and here is video of it hooked up to both the portable TV, as well as the video-noise generator:

The three smaller gears on the front of the gear-box are hooked up to the video-noise generator, the gears on top control the small portable TV yoke.  There is a potentiometer on the front of the box that allows one to control the speed of the gear sweep, and a switch which turns the front motor off.  This is nice inorder to set the manual controls of the noise-generator.

The audio heard is an interesting point to note---most video signals are of much too high of a frequency for us to hear, so i coupled the video signals with the grounding-hum.  This results in one being able to hear the changes in frequency against the harmonics of the ground hum.

So it's all hooked up, Im pretty happy with it so far.  I plan to add more gears to the box which will be connected to a color generating circuit which I will send the video-noise signal through, perhaps to an additional TV to retain the initial noise signal images.

For a long term plan, I hope to just keep adding control modules and additional screens to this thing, until it is very large with many many differing visual elements on different screens.

the end.