I dug this out of the shed yesterday!
It is the first mechanical TV I built when I was 12-13 years old. Honestly it was a terrible design. I made the Nipkow disk out of an old scratched up LP which was belt driven using a rubber band with home made pulleys. The "bearing" was a wooden hub with a nail through it. I am actually really surprised I was able to get a picture at all. At the time I thought it was the coolest thing ever though. It was also one of the first things I ever uploaded to Youtube.
Here is a short video of the disk spinning I took yesterday. Wobbling and all:
youtu.be/nHeHiwPH47g
Unsurprisingly there was no real sync. I powered the motor off of a wallwart through a wirewound resistor I made myself which would cause the disk to run at slightly below the sync speed and I had a momentary switch that would bypass the resistor. So I could alternately press and unpress the button to somewhat synchronize it.
And the first video I published of it working:
youtu.be/YL-Gz9tAkX0
Notice the lack of sync and poor Nipkow hole alignment.
The LED driver was just about as technically sound as the mechanics. I designed it myself without following any plans as I was just learning the basics of using transistors.
The first incarnations was just two yellow Radioshack LEDS, a resistor, 2 AA batteries and a transistor. The audio signal from the computer was just connected directly between the base and the emitter without any bias. The computer I was using was designed to drive unamplified speakers from sound card so it was able to put out over the 0.6V to turn the transistor on during the peaks of the NBTV signal.
I later improved about the circuit a little by upgrading to an array of 5 or 6 brighter red LEDs. I only used one 100 ohm resistor for all of them so the current is shared unequally (bad) and I also added a potentiometer to set the bias point for the base of the transistor (this worked kinda like a contrast control) as well as a coupling capacitor between the computer and the base. So it turned out to be almost a traditional transistor amplifier circuit. I think the addition of the bias was out of necessity because I used a different computer which couldn't output enough voltage to turn the transistor on. I didn't really have a good concept of bias and why it was necessary.
Yeah looking at it seems terrible now but hey I built it on my own based on internet research and actually got a picture. 12-13 year old me was proud of that.