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DIY Collective - some questions?


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Hello

 

I am considering building myself a small-sih collective controller, because I'm fed up with using my X52 Pro's throttle as one because it just doesn't seem right moving a slider forward/backwards, nor does it seem accurate enough.

 

I have a Leo Bodnar BU0836A board, which is currently in a box and hooked up to 3 10k ohm 10 turn pots attached to knobs that I use for trimming air plane axis. Thus I am confident I can make a stick that connects to a pot that is in turn wired into the bodnar board, and probably wiring in buttons at the end of the stick.

 

However I'm having a bit of a problem getting my head around a few things that seem vital in making a collective work as a collective...

 

1. What sort of pot would I use and how would I go about attaching the stick itself to the pot? Could I instead of using a pot use a Hall Effect sensor which I presume would make my next question redundant?

 

2. How would I accomodate in windows control panel or DCS for the relatively short travel in degrees of the collective - as I understand it from flat down to it's uppermost point it would only move something like 30-45� degrees up, thus in the game/windows a pot wouldn't be registering a full turn. So how would I go about resolving that?

 

3. I'm planning on using a piece of PVC pipe (probably 2" OD) but how would I go about adding friction so the stick doesn't move up/down unless I make it? I'm thinking that one solution would be to fit an RC suspension damper minus the spring and filled with oil (or a couple of them) to the back of the pipe (or somewhere to the front end) so they move up and down as the pipe moves up and down but stop the pipe falling, but I'm not sure about that?

 

 

 

Thanks in advance.


Edited by Raven Morpheus
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Yeah that's what inspired me.

 

It doesn't really answer the specific questions I have though. It actually leaves me wanting to ask more questions...

 

Although the brake idea seems a good one, but I can't quite work out how he implemented it. So I'll give the RC dampers idea a go first for friction to stop the pipe falling down by itself. From the measurements I've mapped out in a photoshop pic I only need a 95mm long damper arm for a 12" long collective stick pole...

 

With regards to hall effect sensors I've seen this - http://www.mycockpit.org/forums/content.php?r=88-Hall-Effects-Sensors-to-make-a-joystick

 

So by my understanding of that, I could put a bolt through the end of the pipe I will use as the collective stick to act as the pivot, and on the end of that bolt I could attach a hall effect sensor and have it point directly at a stationery neodymium magnet, so that when the hall effect sensor rotates as I'm pulling the collective up or pushing it down it registers an axis. Would that be correct?


Edited by Raven Morpheus
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I have a Leo Bodnar BU0836A board, which is currently in a box and hooked up to 3 10k ohm 10 turn pots a...

 

1. What sort of pot would I use and how would I go about attaching the stick itself to the pot? Could I instead of using a pot use a Hall Effect sensor which I presume would make my next question redundant?

 

You can use the same pot' as these already used for trim.

The "problem" is:

As you say your collective will turn ~30-45 degrees.

The ordinary pot's that you buy in electronic stores turn around 270 degrees*.

That's mean that you are not using all resolution possible for this axis.

 

*The (pot) manufacturers produce versions with different travel turn, but generally under order, like for example for joystick industry, that use ones

with ~60 degree.

 

Leo Bodnar controller is 12 bit device, that allow 4096 resolution points on axis.

Turning the pot 30 degree you are using ~11% of this resolution, or ~450 points, a bit low for today standards (unless for CH sticks, they still using 8 bits = 256 points). ;)

 

For Windows Control Panel/Game Controls after you do the calibration, this pot 30 degree turn is see as full axis course, or the the virtual collective in game travel is 0 a 100% you you move your DIY collective from 0 to 30 degrees. Only with less precision that is possible achieve. :thumbup:

 

What you can do to improve this?

Use gears (or pulley) to turn the pot - the ideal radio is ~9:1 (270/30)

 

Or use HALL sensor. With these you achieve major resolution with less turn.

Some do this in around 40~60 degrees turn - relative to magnets.

Other on 180~degrees... check the datasheet.

 

The major downsize in use HALL sensor is the difficult to set then properly, due his big sensitivity, the smallest offset is detected.

 

Note that you dont need use all 4096 resolution points, ideally 1000-2000.

 

Sokol1

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Thanks guys. I've ordered an Allegro 1302 hall sensor from Leo Bodnar and I have some neodymium magnets that I can try using so I'll have a play around with it when the hall sensor arrives.

 

Will have to put the main build on hold for a week or two though as I've hit a bit of a stumbling block in my design due to lack of tools - I need a 40mm hole saw, and I don't have the funds to buy one for another week or two. Ho hum...

 

I've got the plan for how the collective will be all ready in my head, just a matter of getting all the bits together and building it and hoping it works.

 

Should work great though and be seriously inexpensive, I am only spending =< £50 on it!!

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