Manual scanner

[andyf97]

Anyone know a way to control the position of scanners using Variable resisitors and two PP3s.

I need to make a small simple unit for setting scanner possitions without a laptop or DAC.

I am thinking we can do this with some pots but not sure where to start and maybe somebody already did it.

+5v -5V X
+5v -5V Y

[mixedgas]

PP9 battery to a lm7805 for regulated 5 V, then a DPDT switch to flip polarity, followed by a 10K pot. Float the battery ground from the ilda connector.

Steve

[andyf97]

Hi Steve

I was thinking in a cleaner switchless way and have differencial.

Did you eversee any LPT1 Dac schematics? I did a long time ago and if I remember it was based on two 0-5V DAC chips and some op-amp circuit to get the differencial.

I suppose what I need is the final stage of LPT DAC circuit and instead of the DAC chips I use pots for X and Y.

[mixedgas]

i'll draw up something this evening

the 8 norms dacs are single ended.

I have one here someplace

[andyf97]

That will be just great of you Steve.

From what I have been looking up in the past 30 minutes I see I need something very simple like:

Battery powered ( Maybe 2 x PP3 ) to get + 0 and -
Opp amp for the + and - swing
variable resistors for X & Y to give the full scan angles.
and a sexy little box with a db25 female.

I suppose we could have a little competition, who does the best one i will send a ..... I must think.

Ahhh, the winner gets a surpize...

[drlava]

Here's one that requires no op amps, so it would be rather static insensitive.



you could use these pots:
ebay item 360140501329
with built-in switch to open the battery circuit for shut-off, but you might just want to use a separate power switch so you can turn it off when the galvos are at the middle

[andyf97]

That is ok but I need to use only 1 pot per axis as eventually i might want to use an analog joystick instead of the pots.

[trwalters001]

Hi All,

I've used ICL7660 Voltaage Converters quite a bit. They work great and they're cheap ($1.37 from Digikey).

Here's links to the data sheet and Digikey:

http://www.intersil.com/data/an/an051.pdf
http://search.digikey.com/scripts/Dk...ICL7660CPAZ-ND

Also, a block diagram of the device andyf97 asked for...

If you need details, let me know.

Tim

[andyf97]

Tim,

Thats looking excellent, can you expand the detail.

Also I have a feeling I have some ICL7660 some place, the part sounds very familiar.

I go to search my box of bits.

[drlava]

That is ok but I need to use only 1 pot per axis as eventually i might want to use an analog joystick instead of the pots.

That uses 2 pots per axis to create differential outputs with a total differential swing of +/- 10V (the way scanners typically are intended to be driven)

If you don't need differential, such as trwalters diagram, then only one pot per axis is needed.