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GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
Daniel Pfeffer27-Jun-23 2:36
professionalDaniel Pfeffer27-Jun-23 2:36 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
CodeWraith27-Jun-23 3:12
CodeWraith27-Jun-23 3:12 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
  Forogar  27-Jun-23 3:24
professional  Forogar  27-Jun-23 3:24 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
Daniel Pfeffer27-Jun-23 3:55
professionalDaniel Pfeffer27-Jun-23 3:55 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
jmaida27-Jun-23 9:31
jmaida27-Jun-23 9:31 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
OriginalGriff27-Jun-23 3:55
mveOriginalGriff27-Jun-23 3:55 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
honey the codewitch27-Jun-23 5:20
mvahoney the codewitch27-Jun-23 5:20 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
DerekT-P27-Jun-23 11:12
professionalDerekT-P27-Jun-23 11:12 
Not racing the beam as such, but spotting the beam, yes.

In around 1981 I built myself a UK101 kit computer; 6502 CPU, (originally) 4k memory and RF output to a monochrome television of 32 (originally 16) rows and 64 columns. Complete with full logic diagram. I'd made various mods to the system, but decided it would be cool to be able to "draw" directly on the screen. This in the days before mouse pointers, tablets, touch-screens etc. I knew the image on the CRT was a bright dot racing across the screen and figured if I had a light-sensitive diode, I could trigger a signal in response to the dot passing under it. That signal was connected to an interrupt and the interrupt processing code accessed what was effectively a hardware tick counter, that was synchronised to the clock for the video driver. Based on the value of that tick counter I could tell where the electron beam would be, and therefore I could calculate a character row and column.

So long as there were some pixels in the character, and a little adjustment to the TV brightness controls, it could detect the position of the light-sensitive diode pretty accurately. Fit the diode in the end of a "wand" and, hey presto, I could draw lines on the screen.

As you can see my grasp of it all was a little tenuous, but the excitement and joy when it actually worked was amazing... especially at the total cost of a few pennies and a couple of dozen lines of assembler code.
Telegraph marker posts ... nothing to do with IT
Phasmid email discussion group ... also nothing to do with IT
Beekeeping and honey site ... still nothing to do with IT

GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
CodeWraith27-Jun-23 13:35
CodeWraith27-Jun-23 13:35 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
jochance28-Jun-23 5:43
jochance28-Jun-23 5:43 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
CodeWraith2-Jul-23 22:28
CodeWraith2-Jul-23 22:28 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
Member 1194113128-Jun-23 6:03
Member 1194113128-Jun-23 6:03 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
CodeWraith2-Jul-23 22:12
CodeWraith2-Jul-23 22:12 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
Member 119411313-Jul-23 10:25
Member 119411313-Jul-23 10:25 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
Juan Pablo Reyes Altamirano28-Jun-23 6:41
Juan Pablo Reyes Altamirano28-Jun-23 6:41 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
CodeWraith2-Jul-23 21:59
CodeWraith2-Jul-23 21:59 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
Matthew Barnett28-Jun-23 6:49
Matthew Barnett28-Jun-23 6:49 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
Member 119411313-Jul-23 9:50
Member 119411313-Jul-23 9:50 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
Peter Shaw28-Jun-23 10:14
professionalPeter Shaw28-Jun-23 10:14 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
CodeWraith2-Jul-23 21:42
CodeWraith2-Jul-23 21:42 
GeneralRe: Did anyone here ever race the electron beam? And did you win the race? Pin
Peter Shaw3-Jul-23 1:32
professionalPeter Shaw3-Jul-23 1:32 
GeneralCCC 27-06-2023 Pin
pkfox26-Jun-23 21:37
professionalpkfox26-Jun-23 21:37 
GeneralRe: CCC 27-06-2023 Pin
OriginalGriff26-Jun-23 21:41
mveOriginalGriff26-Jun-23 21:41 
GeneralRe: CCC 27-06-2023 Pin
pkfox26-Jun-23 21:55
professionalpkfox26-Jun-23 21:55 
GeneralRe: CCC 27-06-2023 Pin
OriginalGriff26-Jun-23 22:02
mveOriginalGriff26-Jun-23 22:02 

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