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Best type of wire to use

Started by Reco, June 19, 2020, 10:29:52 pm

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June 19, 2020, 10:29:52 pm Last Edit: June 19, 2020, 11:05:36 pm by Reco
Hi all

Just wondering what's the best type of wire to use when connecting potentiometer to leo bodnar board
I'm currently using 26awg and wondering if that's  causing some minor issues

Cheers Rhys

Joe Lavery

June 20, 2020, 01:42:22 am #1 Last Edit: June 20, 2020, 01:42:57 am by Joe Lavery
Leo recommends 20 -24 AWG, slightly heavier than you're using but I've used whatever wire I had at the time and have never had a problem. That's generally thin-ish wire anyway.

If you're having an issue I would look elsewhere.
Just :2cw:

'Life isn't about waiting for the storm to pass, it's about learning to dance in the rain!'


Just make sure you use stranded wire, not solid core which breaks often at the junction points
22-24 is perfect. Try also to keep the same color coding throughout the sim.



 For ultimately clean signal use shielded wires and ground the pot's case if it's metal.
I always wire analogue inputs this way.


 Gauge of wire at those diameters doesn't make any noticeable difference.  Use stranded for sure.  If you have any AC wire running close to your pot use shielded wire (attach to ground at one end only) or separate the analog lines from the power lines. Wire gauge is probably not the culprit. A cold solder joint or poor connection at a strew terminal is most likely.

Unregulated, unfiltered power supply like a wall transformer will also cause issues in the system.


Thanks for the advise really helpful. I'm using single wire from the pots to the board

Blue signal
Red 5v
Green earth

At this stage I have only just stripped the end of the wires and wound it round the small turrets. They will get soldered , I wanted to just get things working for a quick play. I though of running 3 wires in some heat shrink tube to keep them tidy. In all the control's are work just a little bit of noise. I'm using vishal 357 potentiometers.  I have the signal wire sorted it's the earth and 5v that I have had to swap around to get them work correctly
I am finding calibration frustrating especially with the x and y axis




Justin'case ...
You do not have to swap wires if they are inverted, FSUIPC can do it for you.



June 22, 2020, 04:43:31 am #7 Last Edit: June 22, 2020, 04:47:02 am by sagrada737
Jack is quite right about not using solid ware for this purpose.  Also, that FSUIPC is quite flexible in dealing with potentiometers (POT) that are "swapped".  But to be clear, the Bodnar card wants to see the correct connection to +5vdc; GND; and Signal (resistance value).

The problem usually is that the orientation of the POT causes the shaft rotation to be opposite of what you expected.   In this case, you can use the Reverse check box in FSUIPC to correct for this.

Another issue that can come up is finding the correct "Mid-Position", such that FSUIPC will read the resistance value correctly, depending on the function required.   For example...  Using a POT to sense Rudder position requires the POT to be mounted with its shaft in its mid-position.  If you do not determine the POT mid-position prior to mounting the POT, then you may encounter FSUIPC calibration issues, where it seems that it will not calibrate correctly. 

I have found that it is best to test the POT on the bench with an Ohm Meter, then mark its mid-position (in the case of the Rudder example), leaving the shaft in the mid-position while it is mounted and secured in place.   Now, while in FSUIPC, when you test the Rudder movement, you will clearly see that the Rudder neutral reading is close to zero value (it doesn't have to be perfect).  Now, you can easily see the effect of values changing by moving the Rudder left and right, and set these positions accordingly.   

For the central Rudder position, you will need to establish a "dead zone" in FSUIPC.   FSUIPC knows this and allows you to set a value to the left and to the right of the Rudder's neutral position.  Setting a good margin here will eliminate issues where you tried to set the value too small, causing the Rudder to be active when it's suppose to be neutral.  I find about 1,000 units either side to be a good margin.  The margin value used may need to be higher if your mechanical system has too much slop/play in it.

As another example that can be a source of confusion in calibration...   For Brakes, it is a good idea to place the POT in its mid-position prior to installation.  This way, when you press the Brakes it will come off its mid-position and register in FSUIPC from neutral to full value.  Again, if the movement is opposite of what you want, then use the Reverse box in FSUIPC to change direction.

As for the Bodnar card "push-in" connections...   I have found that using Bread Board Jumper wires to be a good solution.  The straight Pin on these jumper wires is easy to use with these kind of push-in connections.  Simply cut the jumper wire and solder/shrinkwrap it to your POT cable assembly.

Everyone has their own ideas of how to do stuff like this.   These are a few comments on what has worked for me.

P3d v3.x with Sim-Avionics (two computers), FDS MIP, 3-Optoma HD GT180 projection display driven by a single nvidia GTX980.


For general wiring I have been acquiring lengths of this:

Not expensive. Decent current capability. Clear colours. Ribbon cable allows many wires to be routed tidily. 6-pin can be stripped down to same colour code as 5-pin or 4-pin. Insulation doesn't melt too badly when soldered.


Thanks Mike great reading
I have small cheap ohm meter but must confess not up to the play when it comes to using them, silly question the leads on the meter do they go on signal and volt terminals




Hello Rhys,

There are no silly questions...   Only the ones that are not asked!

Regarding the Volt/Ohm Meter (Multi-Meter)...   Cheap or expensive, a Volt/Ohm Meter is a very useful tool when it comes to building a Sim.  A common use is to check "continuity" of a circuit.   That simply means to check whether or not current is flowing through wires, and how much resistance there is to the flow of current. 

A simple way to see this, is to connect your Volt/Ohm Meter probes to each end of a single length of wire.  The Black probe connects to the "COM" plug on your Volt/Ohm Meter (typically color coded black), and the Red probe connects to the "VOmA" plug on your Volt/Ohm Meter (typically Red). 

When you check continuity, you are checking "resistance" in a wire.  To do this, set your Volt/Ohm Meter Selector for a low resistance value, typically "X1" setting.  When you connect your probes to each end of a short length of wire, you will see the needle move on your Volt/Ohm Meter to a zero or very low resistance value.   Some Volt/Ohm Meters have an audible signal to let you hear if a circuit has continuity.  Perhaps your meter has that feature.

In the case of a potentiometer, there are typically three (3) connections.  A potentiometer is simply a variable resistor of a given value, eg. 10,000 ohms (10K).   This value of potentiometer (POT) is commonly used in our Sims for reading position values.  Typically (but not always), the two outside POT connections are the end points of the total resistance, with the central connection the "wiper" that allows for a reduced resistance value to be obtained.

So...   Connect one probe to either outside connectors, and the other probe to the central connection.  Set your Volt/Ohm Meter for the correct resistance range setting, then turn the POT shaft and see the resistance value change.  This way, you can easily find the POT's central or mid-position.

Thus, when a POT is connected to a game controller, like the Bodnar card, the resistance value is read by the game controller and can be presented and recognized by FSUIPC as a Value, typically -16,380 units to +16,380 units.   For something like a Rudder application, it is within this range somewhere that you set in FSUIPC the limits of Rudder movement, with a value close to 0 units for the Rudder's neutral position.

Anyway... There are much better explanations on using FSUIPC and how to use a Volt/Ohm Meter.   Google these areas for more detail to better understand how to use your Volt/Ohm Meter and how to configure FSUIPC for your Sim.  Below are a couple of links:




P3d v3.x with Sim-Avionics (two computers), FDS MIP, 3-Optoma HD GT180 projection display driven by a single nvidia GTX980.


Thanks Mike

Had a play before your post and got it working, your post is a big help and confirmed I'm on the right track thank you.
It will make things easier to set up the vishay potentiometers to get them centered and that will make calibration easier as well.
Need to work out how to post some pics to
Show sim progress




Quick question does FSUIPC do a better job calibrating than the simple window calibration



Joe Lavery

Yes it does, although you need to read the FSUIPC documents to use it correctly.
Jack Pilot wrote a detailed set of instructions for setting up a TQ, it clearly explains the process, I've converted it to PDF and attached it for you.
I hope Jack doesn't mind?
'Life isn't about waiting for the storm to pass, it's about learning to dance in the rain!'




Here's the results so far. The potentiometer is reading 10.92. I connect the wires to the meter turn the meter to 20k  to check for centre move the potentiometer one direction and get close about 005, mark that on the potentiometer and move the potentiometer the other direction.
This is for the cyclic x and x axis so does it sound like I'm on the right track


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