Recommended rotary and linear potmeters for control column

[andrewarles]

Hi everyone,

Can anyone recommend some good quality rotary and linear potmeters (that can be bought in Europe) to use for a 737 control column conversion?

Thanks very much

Andrew

[Biggles2010]

Hi Andrew,

Rather slow replying to this, but a good source for components in Europe is Conrad Electronics. Very efficient. They have German, UK and French websites.

The resistance you need might be determined by the interface cards you are using, but will usually be 10K up to about 25K. The important thing for rotary and slide potentiometers is that they must have a Linear scale, not logarithmic.

I use these for the control column, and they give smooth operation:
http://www.conrad-electronic.co.uk/ce/en/product/453006/TT-Electronics-AB-4113803545-Rotary-Potentiometer?ref=list

The mechanical range is 295 degrees, but the electrical range is 265 degrees, so I have them geared to use about 260 degrees.

Another possibility with a good reputation is:
http://www.conrad-electronic.co.uk/ce/en/product/424170/Vishay-249-10K-Precision-Potentiometer?ref=list

For throttles, speedbrake etc I use 10K linear slide pots with 60mm range of movement, of which I use 55mm. This gives good sensitivity and leaves a safety margin at each end. The weak point on a slide pot is the vertical blade on the slider. It can break if controls are able to push the slider right to the end of its movement.

The exact sliders I use are not listed now, but these are similar:
http://www.conrad-electronic.co.uk/ce/en/product/441817/ALPS-402125-K-Slide-Potentiometer-RS6011SY-10KD-mono-Lin?ref=list

Hope this helps
jbee

[andrewarles]

Hi jbee,

Thanks very much for your reply.

What control board do you use for the control column. I’ve been hesitating between the Pokeys 56U and the LeoBodnar BU0836X (http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=94&products_id=180).

Is there a difference between the two (for the control column use)?

Do both give the same smoothness/sensibility?

Thanks

Andrew

[Biggles2010]

Hi Andrew,
I've used the Leo Bodnar boards and found them to be faultless. I'm using one BU0836X and a BU0836A in the pedestal and five BBI-32 boards for the MIP and overhead. I've no experience of the Pokeys boards, so I can't compare them.

For the control column I use a BU0836A as a dedicated interface for ailerons, elevator and a number of pushbuttons on the yoke.
It's a 12bit board so has very high resolution.

The smoothness and sensitivity of the controls will depend on several things other than the interface board. Like quality and range of movement of the potentiometers, the ranges of movement of the yoke and control column, and the type of bearings used for their pivot points.

jbee.

[tiburon]

Hi,

For a far more reliable and spike-free experience I suggest you take a look at Hall Effect sensors. They do the same as potmeters but without moving parts so no spiking or wear. A few hardware manufacturers already use them and I saw several articles on how to implement them. Very interesting.

Martin

[andrewarles]

Thanks Martin,

I'll take a look at them.

Are you suggesting that even with good quality rotary potmeters spiking will occur?

Andrew

[tiburon]

Euhm, not necessarily, but it remains susceptible to dirt and wear so the chances of spiking are always there.

[Zlatko]

Sorry to interfere, but I believe my question is well within the topic of the discussion.
What i would like to ask is - is there a way to connect only one hall effect sensor per axis ( since all ready made cards - Leo Bodnar's , OC's , etc,. utilise one axis per analogue input) and to achieve good level of accuracy.
I have a reason to believe , most manufacturers who utilise hall effect sensors, use more than one ( 3-4-5 ) per axis and tie them to multiple analogue inputs of a micro-controller . Or alternatively - they use ready made contact-less pot's based on hall effect sensors with some pre-processing of the signal before feeding it in an analogue input.
Is there proven and working schematics how to position and read those sensors in order to read one particular axis?
I myself am on a crossroad which way to go.
Regards
Zlatko

[tiburon]

Hello Zlatko, I'm sorry but I can't help you there. I didn't know manufacturers used more than one on the same axis and I have no experience in using them myself. But since they are dirt cheap I certainly am going to experiment with them.

Martin

[Zlatko]

There are some ready-made hall-effect potentiometers.
Like this: http://www.potentiometers.com/select_hall.cfm

I don't know their internals ( never had one of them ), but as you say Martin, it is worth trying. The best of all - they are with endless rotation and only 3 terminals pop out of them ( as what we are used to see on a standard pot).

[tiburon]

It's just a chip that reads the angle of an external permanent magnet rotating around it. You connect them the same way as you would a potmeter. Those ready made solutions look very interesting indeed !