Cheap String Pots

[tmcnam]

Hi All,
This is probably old hat to most of you and seems pretty obvious once I made it but I am converting my 737-300 TQ for my sim and needed some string pots. After falling out of my chair when I saw the price ($180+!!) I decided to build my own.

As you can see from the pics, I machined a small, 2 groove "pulley" from a bolt I had laying around. I used my lathe but you could easily rig up something similar from washers and nuts on a bolt through which you would have to drill for the pot to fit in. I used a retractable badge reel which you can get from Ebay for about a $1.50. I bent up a piece of aluminum and hot glued the badge reel to it. I used a wood spacer to align with the small pulley. The pics are pretty explanatory.

You can make the grooves different sizes to get the exact range you need depending on of your using a 1 turn, 5 turn or 10 turn pot. For example, if you make the retractable reel groove .5" in diameter it has 1.57"/turn (diameter x pi) so a 10 turn pot has a range of 15.7". Or you could make a 2" diameter pulley size and have a 6.3"/turn pot which would be useful with a 1 turn pot.

62736274627562766277

[tmcnam]

More pics of the cheap string pot.

6278627962806281

Also here is a youtube link of a video of it:

http://www.youtube.com/watch?v=rGB2NAki0PI&context=C313ddc4ADOEgsToPDskLrnf2vnUfP1zKwj5xJ62iL

[tmcnam]

Another youtube link to better illustrate:

http://www.youtube.com/watch?v=GnQHJV7R4UI&feature=youtu.be

[Tom_G_2010]

Hi All,
This is probably old hat to most of you and seems pretty obvious once I made it but I am converting my 737-300 TQ for my sim and needed some string pots. After falling out of my chair when I saw the price ($180+!!) I decided to build my own.

As you can see from the pics, I machined a small, 2 groove "pulley" from a bolt I had laying around. I used my lathe but you could easily rig up something similar from washers and nuts on a bolt through which you would have to drill for the pot to fit in. I used a retractable badge reel which you can get from Ebay for about a $1.50. I bent up a piece of aluminum and hot glued the badge reel to it. I used a wood spacer to align with the small pulley. The pics are pretty explanatory.

You can make the grooves different sizes to get the exact range you need depending on of your using a 1 turn, 5 turn or 10 turn pot. For example, if you make the retractable reel groove .5" in diameter it has 1.57"/turn (diameter x pi) so a 10 turn pot has a range of 15.7". Or you could make a 2" diameter pulley size and have a 6.3"/turn pot which would be useful with a 1 turn pot.

62736274627562766277

Very nice! Any chance you could add a couple pic's showing how the retractable badge reel integrates with this?

[tmcnam]

Hi, Those posts had to be cleared by the moderator so it didn't make much sense until you see the rest of the posts. Sorry about that. They are there now. I had to divide the posts because of the 5 picture limit. Also check out the first youtube video; it shows how it works.
Thanks,
Tim

[Tom_G_2010]

This is great stuff!!! I wish I had seen this before building the slide pots into my throttles and breaks. Well, now I know what to replace them with when the slide pots wear out. :idea: And, this may just be the perfect solution for my rudder and elevator sensors that I am still working on. I priced precision position sensors for them several months back and at $180 + I tossed that idea. This looks like the perfect DIY solution.

THANKS FOR POSTING!!!!!!

[sully1071]

Does it take a lot of knowledge of electronics to build this system? i like the idea but only have a very basic knowledge of electronics.

[tmcnam]

Hi Sully,
No, not at all. This is just hardware stuff. The potentiometer itself is just a standard pot that is typically used hooked to 5v and Ground with the wiper going to an analog input to your favorite io card (OpenCockpits, Leo Bodnar, PoKeys, Epic, FDS, Arduino, Phidgets etc)!

Best Regards,
Tim Mc

[sully1071]

Thats good, just wonderin if it would be possible to connect this to labview, i presume it would be. THanks

[tmcnam]

Labview is absolutely made for just such hardware. I'm not sure how easy it would be to integrate into FSX or other as I'm not very familiar with LabView but I'm sure it could be done without too much trouble. LabView is known for its ease of connection to just about everything.

Best of luck.
Best Regards,
Tim