Sinclair ZX80 / ZX81 / Z88 Forums

Hi,

A new project from the "Haut-Parleur" magazine (1989).
It read a picture from an analog signal, to a ZX81/SPECTRUM analog card.

Article: (French)
http://zx81.ordi5.free.fr/brico/scanner/




Scanner's head , motor card and computer's card:

Electronic switch (Alispeed link)

PWM DC MOTOR CONTROL (Alispeed link)

Kicad v6:


PCB Thickness= 1.6mm
(estimate price 2$ + Shipping for 5 PCB)

Hi,

In this project, the IR gate is located on the head, not in the cylender right side.
Just fixe a reflective aluminium stripe to get the picture start synchronization.
Keep in mind that the signal is a positive value, not a 0v value.
Tip:
If you had to buy several white crystal LEDs, you can cut the LED and retrieve its lent.
Take a heat-shrinkable sleeve to assemble them on the photoresistor.

Kicad v6:

- 4 PCBs (2 for the right side, 2 for the left side), PINs 1mm to join both PCB.
- color black
- PCB Thickness= 1.6mm
(estimate price 9.4$ + Shipping for 5 PCB)

Note:
This device can be wired directly on the sound ZX81/SPECTRUM's input...
Hight sound level = white & low=black.

Exemple: (french) "Donnez des oreilles à votre ZX"
http://zx81.ordi5.free.fr/n3/download/O ... _03_36.png
http://zx81.ordi5.free.fr/n3/download/O ... _03_37.png

Any claver ideas to get the acknowledge signal ? a key pressed, a specific voltage ?

I may be wrong, but it looks a similar concept to the light pen for the Spectrum, it was for the main part a software trick

Hi Stephano,

Yes, but the light pen was powered by a photodiode, not a photoresistor.
photoresistor=256 colors.
photodiode=2 colors.

The photoresistor was used on old gaming pads for guns. On a screen, the light pen need to get the line screen syncho on the bright colors.
But, we can use the BPW42 diode to get B&W colors on this scanner!

CPC light pen: (Photodiode)
http://zx81.ordi5.free.fr/cpc/

ZX81 light pen MAGECO:
http://zx81.ordi5.free.fr/vtr/download/ ... AGECO].pdf

Spectrum light pen MAGECO: (Photodiode)
http://zx81.ordi5.free.fr/vtr/download/ ... AGECO].pdf

More infos:

Search "belinograf" ("Bélinographe")

Wikipedia

Youtube video:
https://youtu.be/8J9izchM9C0

When the TV brightness passed a threshold, the raster picture was generating a buzzing noise which was received by a software loop.
The software was changing the brightness of video portions to find the right spot you were pointing at
A scanner requires an audio oscillator I think?

Exact, some light-pen only use the software to localize the light spot.
DATEL is a simple electronic card how use this process in the Light-Writer solution.

http://abandon.pcbs.free.fr/datel.htm

http://zx81.ordi5.free.fr/CartesZx81/Da ... ghtWriter/