adding potentiometers for scanning size (how to ? )

[laserjohnn]

was searching for this and found this forum on google so decided to join and ask it here
i am a laser hobbyist for a few years now and like to adjust my projectors.

currently i have a projector but that does not have a size adjustment.
on the inside i have the following signals:
X+ GND X-
Y+ GND Y-

i assume it is possible to put a potmeter between these lines to adjust the scan angle?
if yes what value should i have and how to connect it ?
i think i need 2 potentiometers, one for each channel ?

is the following correct? what do i do with the X- ?

[megaton]

You need two 10K ohm double pots for do this.

One for + one for -
like this.
Pin 25 is GND

[Steve Milani]

I apologyze if I'm jumping inside discussion...

What kind of 10kOhm double-pots have to be: Linears or logarithmics?

[megaton]

I apologyze if I'm jumping inside discussion...

What kind of 10kOhm double-pots have to be: Linears or logarithmics?

Linears, I think is best but not mandatory

[Steve Milani]

Linears, I think is best but not mandatory

Ok... Thanks Mega!

[megaton]

Ok... Thanks Mega!

Glad to help.

Cheers,

[laserjohnn]

Thanks megaton!
but how do you decide the resistance value?
as i also heard 50K or even 100K would do the trick.

for the color modulation channel i could use single potmeters right ?

[megaton]

Thanks megaton!
but how do you decide the resistance value?
as i also heard 50K or even 100K would do the trick.

for the color modulation channel i could use single potmeters right ?

I also try 50k and 100k and work, but I have better results with 10k, mostly for the
Color modulation, In my application 50k and 100k don't work properly,
and YES I put single pots for this.

I hope this is clear. My English is not my first language.

[laserjohnn]

perfectly clear, thank you! works very good now