Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: Commanderbob on January 31, 2010, 04:54:23 PM
-
I'm looking for a slide potentiometer that has a travel of at least 6". The longest one I've found was 100mm (about 4"). We need it to be able to tell where a pneumatic piston is.
-
Hi,
You could get lucky searching among professional stage lightning sites, but be ready to pay through your nose if you do.
Alternatively, you could use a system like what's used on old radio scales, with a string where one point is moving with the piston and then driving a rotary pot with a pulley with a diameter made to match the length of travel to the around 270° travel of the pot.
There are other methods as well, but how precise do the readout need to be?
-
+1 for sting and pulley. I've never seen a 6" linear pot before.
-
Hi,
Here's one for those with deep pockets (http://www.omega.com/pptst/LP802.html)
And here's a PDF with some (http://www.intertechnology.com/Celesco/pdfs/MLP.pdf)
-
why don't you just use a lever action with a smaller linear pot.? you have one end on a pivot and the other on the moving object and the shorter linear pot. in the middle.
-
Yea these are used in industry like what Soeren said, but you pay a heavy price for reliability and ruggedness.
You can also make you own from a straight or spiral length of electric heater wire/etc.
I'm looking for a slide potentiometer that has a travel of at least 6". The longest one I've found was 100mm (about 4"). We need it to be able to tell where a pneumatic piston is.
-
I found one on this site that has 5 inch travel. It's motor driven though, but if you don't need the motor you can just remove it.
http://www.alltronics.com/cgi-bin/category.cgi?item=28P006 (http://www.alltronics.com/cgi-bin/category.cgi?item=28P006)