GT5 channel 5 and 6 mod

[josh9mile]

Months ago I saw a post somewhere (probably Facebook but I'm not sure) about changing the ch 5 and 6 dials to 3 position switches. I scrolled right by it because it didn't interest me and I didn't have a gt5 anyway. Well now I have one and I would really like to convert to those switches. Does anyone know where I could find info on that?

 

[OnTheTrail]

Interested in this as well.

 

[heyok]

If no one is able to find a link on the process by tomorrow, remind me and I will try and document what is needed. I should be able to find the time then.
I can tell you that you will need a couple of resistors. Use 4K7 or 10K, and a single pole double throw switch that has a center off position.
Cheers,
Al

 

[josh9mile]

If no one is able to find a link on the process by tomorrow, remind me and I will try and document what is needed. I should be able to find the time then.
I can tell you that you will need a couple of resistors. Use 4K7 or 10K, and a single pole double throw switch that has a center off position.
Cheers,
Al

ok, im reminding you....lol

 

[heyok]

ok, im reminding you....lol

Thanks!

Here you go:



Let me try and explain what is happening. Keep in mind that I haven't seen the inside of the transmitter you are working with, so this is kind of a generic way to go about changing from an analog channel to a three-position channel.

At the top left is the potentiometer (call it a "pot" for short) which is the knob you turn on your transmitter. It has three connections to form what is called a voltage divider.
Usually, one wire is connected to +5 volts (sometimes it is more like +3 volts) and one is connected to ground. The third wire - the one in the middle - is mechanically driven by the knob to a resistive element that is fed by the first two wires I mentioned. As you rotate the knob, the center wire is more toward ground or toward the positive connection or it could be anywhere in between. Depending on how far you turn it determines the voltage on that wire.

Note that the color of the wires is not important. I just stole these pictures from some web page and reused them as they were.

We will be disconnecting that pot and replacing it with our own little circuit made with two resistors and a single pole double throw center off toggle switch (usually abbreviated to SPDT Center Off).

What we want to do is simulate that middle connection by creating our own voltage divider. That is what the two striped components are for. These are 10K ohm resistors. If you were to connect a volt meter from the bottom of the lower resistor with one lead and to the top of the resistor with the other lead, you would read some voltage. Now move one probe to the center connection and you would read one half of that voltage. In this way, we are simulating the pot being in the center of its travel. The toggle switch is going to connect that center wire to one end or the other of the two resistors, or to nothing which means the transmitter will see the 1/2 voltage measurement.

I've done this mod a few times for guys that had something like a DX6i stick transmitter. I did it a little differently though as I added a second toggle switch so that you could choose from unmodified operation (the stick) or the three-position switch.


I've probably left out some details, so if something doesn't make sense or you feel it could be described better, please let me know.

Cheers,
Al

 

[bryantjt]

I'm in the process of doing this right now. You will have to grind away some material from the switch mounting location in the radio case. The POTs are much thinner than the switch bodies.

 

[heyok]

I'm in the process of doing this right now. You will have to grind away some material from the switch mounting location in the radio case. The POTs are much thinner than the switch bodies.

Nice!
Show some pictures so we can know what is inside.

 

[Airmaxx23]

Here's my post from Facebook that you're trying to find on how to do the mod with 2 position switches.

https://www.facebook.com/groups/265365123944286/posts/1141293756351414/

 

[heyok]

Here's my post from Facebook that you're trying to find on how to do the mod with 2 position switches.

https://www.facebook.com/groups/265365123944286/posts/1141293756351414/

Nicely done!

 

[josh9mile]

Here's my post from Facebook that you're trying to find on how to do the mod with 2 position switches.

https://www.facebook.com/groups/265365123944286/posts/1141293756351414/[/QUOTE

Awesome! So those are just on/off switches? No center position? Was hoping to use as a winch controller since I'm already using the 3 position switch on my gt5 as a 3 position dig

 

[heyok]

I showed you how to do it with a center position!

 

[bryantjt]

I've got this wired up and can only get channels 5 and 6 to change position once looking the epa screen. I used 2.2k ohm resistors based on another post describing this setup. With a switch centered (B position) I measure from one side to the other (pins A B C) AB 1.13V BC 1.13V AC 2.26V. Switch moved to A position, AB 1.72V BC 0V AC 1.72V. Switch moved to C position, AB 0V, BC 1.72V, AC 1.72V.

Not sure what the issue is.

https://photos.app.goo.gl/DJcrGvNCKDDMCWAk6

https://photos.app.goo.gl/HpPueh9FGgfyz5Kq6

 

[heyok]

Please post a photo as that would help.

 

[bryantjt]

Photos in the links, they wouldn't embed.

 

[heyok]

I see them now. Thanks.

The way you posted the voltages makes me confused.
Put your meter probes on of the outer pins. That should show a voltage. Swap the probes around if you get a negative reading.
Now put the red probe on the center pin.
Move the switch to the three positions and write down the voltages.
From what you posted, I think this is what you get:
Bottom position = 0
Middle position = 1.13
Top position = 2.26

If that's the case, it should work.

If you temporarily put back the pot, you should get similar values on the voltmeter if you crank it to one end or the other or center it.

 

[bryantjt]

Outer pins 2.26 only if switch is in the middle
Following the rest, red probe centered, black probe on the end pin.
Bottom 1.72
Middle 1.13
Top 0

 

[heyok]

If you put the pot back, what are the minimum and maximum voltages when you rotate the pot?

 

[bryantjt]

Pot in place, always 2.37 across the outside pins.
Full lock one way 2.37 bottom to center
Centered 1.13 bottom to center
Full opposite lock 0 bottom to center.

 

[bryantjt]

It almost seems as if I need a diode so I can get full voltage at top and bottom switch positions.

 

[heyok]

"can only get channels 5 and 6 to change position once looking the epa screen"
I don't see anything that could explain that.