Can I use this actual aircraft potentiometer?

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Kaellis991
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Re: Can I use this actual aircraft potentiometer?

#61 Post by Kaellis991 »

Joe,

Well, I finally have the switch panel put together with the new CTS pots. Those worked out perfectly.
On this switch panel I have 7 toggle switches (bat, alt, fuel pump, 3 for lighting, pitot) along with the two light dimmer pots, one of which has the on/off switch. There are 10 total pins to be used on my Arduino.

So I have a couple of questions to get clarified.
1. Did you say I should add a 220 ohm resistor between each of the 10 wires and the 10 pins on the Arduino?
2. Just to clarify the connections for the pots, I’ve forgotten. will those be set up as voltage dividers with the two side pins on the pots connected to GND and 5V with the center / wiper connected to an analog pin? So in total I will be using 8 digital and two analog I think…

Sometimes I just can’t remember what I did/ saw / read a month ago.

Kirk

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jph
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Re: Can I use this actual aircraft potentiometer?

#62 Post by jph »

Hi Kirk,
Yes, exactly. Use a safety 220 ohm on all inputs including the Analog. And as you say, the analog portion is a potential divider with the pot outer pins just as you describe and the wiper to the analog input pin (via the 220 ohm.)
What was the panel that had the electro magnetic actuator/hold on the switch ? - or was that another project I am thinking of ?
Cheers
Joe
Joe. CISSP, MSc.

Kaellis991
Posts: 581
Joined: Mon Sep 07, 2020 8:49 am

Re: Can I use this actual aircraft potentiometer?

#63 Post by Kaellis991 »

jph wrote: Sun Jul 03, 2022 12:52 pm Hi Kirk,
Yes, exactly. Use a safety 220 ohm on all inputs including the Analog. And as you say, the analog portion is a potential divider with the pot outer pins just as you describe and the wiper to the analog input pin (via the 220 ohm.)
What was the panel that had the electro magnetic actuator/hold on the switch ? - or was that another project I am thinking of ?
Cheers
Joe
Hey Joe,

Thanks for the reply. So I did have it correct. I just have to find an elegant way to incorporate those resistors. I’ll probably make a small PCB with Input and output connectors and place all the resistors on it. Not sure yet, but I want to incorporate all the resistors on a board.
Edit: After looking at my setup, maybe splicing the resistors inline with the wire and adding shrink wrap over the soldered connections and the resistors will be a better way.

The magnet switches are with the autopilot module which, because they use the ULN2803 and my 15V power supply, will be integrated with my landing gear lighting and gear switch. I’m still working on getting the power supply for the magnets and gear lights connected to the ULN2803.

I probably knew this back some months ago, but I assume I should add the 220 resistor to the gear toggle since it is connected to the Arduino. Also the two autopilot switches (A/P and heading mode) should also each have one since they also connect to the Arduino with a digital pin. When the autopilot switch pins go high they activate the darkington to close the ground side of the magnet circuit coming off the power supply and then energizing the magnets to hold the toggle switches closed.

If I understand this correctly, the gear lever switch will activate datarefs in Xplane which the AM script reads and then sends either a high or low to the corresponding pins for the (3) gear lights plus the intransit light to make those pins go high or low and thus activate the darlington to turn on or off the power to the lights.

Am I on the right airway?

Kirk

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jph
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Re: Can I use this actual aircraft potentiometer?

#64 Post by jph »

Hi Kirk, yes that's all more or less spot on.
It is always the best practice to put a 200 ohm resistor on ANY input - analog or digital. Outputs not an issue depending on what it is driving. In almost all cases no issues on output.
Yes wrt the gear. Basically the arduino reads the position of your gear switch and AM sends this to the X-Plane. AM Also is monitoring for the state of the Indicator lights for the gear and will drive the Arduino pins accordingly.
I do remember the AP thing now :D
All coming together mate ! Nice.
British F1 GP just about to restart so back to the F1 live stream ;)
Joe
Joe. CISSP, MSc.

Kaellis991
Posts: 581
Joined: Mon Sep 07, 2020 8:49 am

Re: Can I use this actual aircraft potentiometer?

#65 Post by Kaellis991 »

Joe,

At least the white flag is not so far away now.

Kirk

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