Pots - linear or logarithmic?

[Padser]

~S~

I have finally got round to building my 'trim box' to supplement my CH set up with some rotary controllers for trim and prop pitch.

I used the circuit board and USB cable from an old MS Sidewinder Precision Pro with four new potentiometers (100k ohm logarithmic - about 50p a go), some knobs that fit the pot shaft (about 60p each) and a project box (I think

[JBaymore]

Padser,

Nice work there...... clean and professional looking.

I am guessing that you'd really want a linear taper on the pots.

[Padser]

John,

Thanks for this - I suspected that it might be the case. The response to the inputs is a little twitchy, though manageable (and in my current sim of choice it is easy to adjust for sensitivity, which mitigates this to some extent). Still, for someone of such little electronic knowledge as myself, I got a real buzz out of putting this thing together and getting it to work at all!

I will have to get hold of some linear pots and break out the soldering iron out again... they are pretty cheap anyway so it won't make for an expensive experiment and now that the box is ready with holes and what not drilled it shouldn't take more than a few minutes to fix. I'll post results when I've tried it.

Re the guy in the shop - he was busy and looked pretty hassled at the time and I think may have been working outside of his area of expertise.

To give Maplin's their due though, another fellow I had spoken to on a previous occasion was both (a) excited and enthusiastic about the project and (b) really did seem to know what he was talking about - he suggested bringing the original in but unfortunately wasn't around when I went back. Typical, eh?

[bubba3884]

here's a link to device which is basically the guts to a large joystick. the fellow has a good description of which pots to use (linear) about 3/4 of the way down.


http://www.lbodnar.dsl.pipex.com/joystick/index.html

[Padser]

Thanks -  I will remember 'linear taper B' when I go to the shop next time...

If I knew how to wire a 6 x 6 matrix I might even have a go at this... I understand the principle involved - connecting row 1 to column 1 creates switch 1 when the circuit is closed, etc, but how on earth would you wire 32 separate switches to such a small component?

Am sure I'm showing my ignorance here...

Cheers,

Pads

[TacitBlue]

32 switches? lol, try 101!

Looks like a mess doesn't it? This is a hacked keyboard controller that controls my switch panel. I do not reccomend hacking a keyboard.

The way I did it as you can see, was to attach each contact to a screw terminal. When I add a new switch, all I have to do is screw the leads in place and I'm ready to go. You can figure out what combination of contacts coresponds to which button pretty easily. Once you have all of them hooked up to the terminals, take a piece of wire and try all possible combinations. Do this with the joystick properties window (control panel>game controlers>[joystick name from list]>properties) open. watch and see which button lights up, and write down the combonation.

It isn't that easy with a keyboard, I had to use one of those monitoring programs that records keystrokes. Anyway, I hope that helps. ANd please don't hack a keyboard.

[JBaymore]

Padser,

Congrats on getting the electrical work done....... you are now an official "soldering iron jockey".

[JBaymore]

Tacitblue,

Thanks for the picture!  Nice hack job there.  It is about time you posted some pix down here.     So show us the rest of the stuff you are working on.   Like the other side of the keyboard hack.... what does it hook up to?

Oh....... and please watch the image filesize just a bit    ...... that one above is 105K....pushing the boundaries a hair.  And everyone remember ........this thread can only take about two more 100 K shots before we hit the 500 K limit in one thread.

best,

........john

[Padser]

I'll post results when I've tried it.

Just to confirm, the 10k linear pots are excellent and give a much smoother and more even range of inputs.

This has really become part of the way I fly now  very pleased with it. Am experimenting with Leo Bodnar's clever little joystick controller now to see about adding some switches to the equation.

Just what I needed, another obsession...  ::)

BTW - anyone found a way of sourcing those little plastic connectors and plugs for connecting to circuit boards like this? Had really trouble finding some today - the best I found were Futaba Servo Plug Kits - any other suggestions?

All the best,

Pads

[TacitBlue]

John,

I shrank my image a little. I didn't realize it was so big.

I'm pretty sure I posted pics of my setup once, but it would have been a long time ago, possibly a year or more. I'll try to post some more tomorrow, if anyone is really interested.

[JBaymore]

Tacitblue,

Of course we're interested.

[JBaymore]

BTW - anyone found a way of sourcing those little plastic connectors and plugs for connecting to circuit boards like this?

Padser,

Try PartsExpress ....it is listed in the "Resources" sticky at the top of the Forum.

best,

..................john