6 Pos 2 Pole Rotary Switch with LED's for Mode Selection

[LTMNO]

LTMNO, I looked into the switch and led thing and I'm curious why you used the six pole switch if you were going to use only five? Digikey carries this one too and it's only five position.

http://www.digikey.ca/scripts/dksearch/ ... CKN6046-ND

Hi JustinTime,
I actually had all intense purposes to use all 6 modes/switch positions....
but when i fitted the LEDs I was disappointed when I could only use 5. That being said, I rationalized and just worked with it.
I hope that answers your question.

Pino

[JustinTime]

Cool, LTMNO. You made such a strong case for the rational of using 5 positions instead of 6 that I wondered what's up.

[LTMNO]

Hi JustinTime, Its all good, the mod is for a 6 position switch originally. If I can swing something with the leds, i will. My digi-key order came yesterday... i will open it soon when I get a chance. After the weekend, i will fire everything up and solidify the solution. Have a great family weekend all. Its Family day in Canada and President's day in USA.

[LTMNO]

Okay, I was able to get away from the kids for an hour or so... here are the LED's that i just recieved. I think the Amber ones can work if i break them and stack them nicely.

The greens ones are worse(they looked good in the pictures).

Some More goodies...


This is a 5K Trim Pot that I am going to try to use to figure out the correct Ohms Resistance for each position

This is a set of LED Rings that can be used to cleanly cover the LEDs when i drill the hole in the Case

Another LED Array that could potentially work, I have 2 of them to i will just remove 2 from the bank of LEDs

Here is the Knob that someone asked about and it cost $1 from Electronics store called Sayal Electronics.

[DroneBuilder]

Ha ha - that was me asking about the knob, and I am following this thread closely, eager to find out the final solution!

I like that the model number of the knob is haha-111.

To follow-up on my prior question: I am still not clear - can your solution ultimately be used with six positions and six leds?

Thanks again for sharing your knowledge, and your journey! This is really fun for me!

Sincerely -

DroneBuilder

[ReSt]

I still believe, you should use an odd number of switch positions.
Sometime you will have to adjust your sticks.
And that means, you have to set the sticks - and the pots - to middle position, that will be assigned as pulse length of 1500 usec.
But with a 6 position switch that simulates a pot, you can either switch to pos 3 or 4. And this position will represent 1500usec afterwards. And all the other positions will be proportionally spaced between 1000 us to 1500 us and 1500 us and 2000 us.

They will no longer be spaced proportionally from 1000us to 2000 us.


Reinhard

[LTMNO]

@DroneBuilder... The answer to your question is YES. Thanks for following... I am almost done but I won't really be able to complete til tomorrow. I just snuck away check my email here at home.
You can totally do a six mode select, as that is the way it was done before I attempted to do 5 positions. I originally wanted 6 positions but when I found that i can't have all 6 LEDs on the radio where i wanted it, i rationalized to having 5 LEDs.
I think it was ment to be as to @ReST point. He is absolutely correct and truly I think 5 Positions looks better on the radio, more room to label the faceplate and the knob can turn those 5 positions at 30degrees a position with enough space to actually have the white line point to the LED. Like I said, my trial and tribulation was with meaning.

You can add another Resistor and another LED and have your 6 positions. Check out the DIY threads or perhaps there is one here to in 9xForums.

Just to note, it was the 6 Position Mode Selection solution that mine was based on.

Thanks.

[JustinTime]

Unless I'm totally wrong about how the pot is wired to the system, all you need is four 1.25K resistors connected between the five positions you are going to use. If you are going to use six positions than the value should be 1K. Is that not how it should be?

I'll go over to the other forum you referred to and see if I can find the thread.

EDIT: I read the blog of ARHEXA here http://diydrones.com/profiles/blogs/6-pos-mode-switch and he recommends using the resistors like this, starting at ground going to +5.0v, 3k9, 1k3, 1k3, 1k3, 2k2. It seem that there are some resistors internally (before or after the pot) that affect the values.

EDIT 2: After looking at all the option I have to agree that 5pos is the best solution all around. I'll wait for you to measure the four resistor values and then I'll order the stuff from DigiKey.

[DroneBuilder]

@DroneBuilder... The answer to your question is YES. Thanks for following... I am almost done but I won't really be able to complete til tomorrow. I just snuck away check my email here at home.
You can totally do a six mode select, as that is the way it was done before I attempted to do 5 positions. I originally wanted 6 positions but when I found that i can't have all 6 LEDs on the radio where i wanted it, i rationalized to having 5 LEDs.
I think it was ment to be as to @ReST point. He is absolutely correct and truly I think 5 Positions looks better on the radio, more room to label the faceplate and the knob can turn those 5 positions at 30degrees a position with enough space to actually have the white line point to the LED. Like I said, my trial and tribulation was with meaning.

You can add another Resistor and another LED and have your 6 positions. Check out the DIY threads or perhaps there is one here to in 9xForums.

Just to note, it was the 6 Position Mode Selection solution that mine was based on.

Thanks.

I see! I did not think about how nice it would be to have the line on the knob actually point to the lit led! I don't really even know why I want six leds - I don't even plan on using this for Ardu-projects -- at least not right out of the gate! So I guess I thought "more is better" (After all, I AM an American )

So that leads to two questions, one of which is already asked --
1) Now I am confused why we would not use a 5-position switch (edit -- now I read your answer above! So I assume when I do the mod, I can use the 5-position switch, right?)
2) Why not use the variable trim-pots between each position on the switch, which would allow you to more accurately (and maybe more easily) establish the pwm values actual output at each setting. (That is, I see that this is the solution employed by the eBay seller, and it seems like a reasonable solution.)

I apologize for all the questions. I know very little about this stuff, and so if my questions seem rude, please know that it is only from my own lack of knowledge!

Thank you very much for posting your work! I am looking forward to adding this mod to my tx, and it is especially nice to know that you are pioneering the way so that it will be easy for the rest of us!

Thanks again --

DroneBuilder

[jhsa]

You can use 6 positions as long as one of the positions matches 1.5ms which is the channel value when the pot was at center. About the variable resistors, the problem when you connect them between pins is that when you adjust the second trimmer you will mess up the first. On the third you'll mess up the other 2 because they are in series.

[sgofferj]

I think he meant, when you re-calibrate after installing the switch.

[LTMNO]

@DroneBuilder - firstly, this is a forum, so ask all questions, as there are no wrong ones.... I always make mistakes, I will always need help... I hope that all forum topic threads are helpful to you as they are to me.

secondly, regarding...

"So that leads to two questions, one of which is already asked --
1) Now I am confused why we would not use a 5-position switch (edit -- now I read your answer above! So I assume when I do the mod, I can use the 5-position switch, right?)
<ANSWER> I have stumbled on this 5 position mode select, like you I have read everything else and just assumed that the 6 position was the thing. i am not sure on the follow up on the other solutions and if people are commenting on recalibration etc. JHSA and others have brought up good points about center position etc and the recalibration problem. The APM has a 6 mode select option. I have not investigated whether or not, i can modify that to just have 5 instead of 6 so that it is not looking for a 6th position. The goal for me is to have my 1st or 5th position to cover the spread of 2 positions in the APM.</ANSWER>
2) Why not use the variable trim-pots between each position on the switch, which would allow you to more accurately (and maybe more easily) establish the pwm values actual output at each setting. (That is, I see that this is the solution employed by the eBay seller, and it seems like a reasonable solution.)"
<ANSWER>My answer to this question is simple... someone has already figured that out, I have not tested it but I am positive it is working as people are buying it and the Gentlemen that who created it is doing something right. I like the idea of having a resistor there that is static and constant. I don't want to leave room/margins for movement, vibration, error. If I get the perfect value settings and am able to just have a resistor in place of a variable pot(which is what we replaced essentially) then that would be a repeatable solution that I would like to exemplify.</ANSWER>

Keep the questions coming, I will do my best along with others here to answer them. Today I hope to have this solved. I just need to get the day started here.

[MikeB]

I'll look into changing the calibration. For the sticks, the centre position is important, but for the pots it isn't. I've seen that Bertrand has a change for the pots where centre position for the pots is simply calculated from the two end positions. This seems a better way of handling the pots, and would solve the 'centre' position for this switch.
I'm not sure when I'll get this done, working on other things at present.

Mike.

[LTMNO]

Hi Mike, that would be fantastic... truly! Thanks for your input.

[MikeB]

I've slipped the code change in, but need to test it and finish the other changes I'm doing before it is released.

Mike.

[LTMNO]

Hello All,
I did finally get my APM up and running and was able to monitor the PWM from the Radio Receiver to the APM as I was adjusting my inputs.

It is important to note that the way that it is now, that when I do a calibration on the radio and set the midpoint to the middle switch. Nothing Changes....
Everything works and the mode selects are not affected. This is good news.

I think instead of everyone buying trim pots and adjusting them to their radios... that a resistor solution on a small pcb that connects to the switch and LEDs is the right solution. At a minimum, just through-hole resistors connected in a certain fashion would be good to.

I have calculated the resistive values for the divider solution of 2 resistors per pole/switch position and am just going to solder a test bed now. The breadboard was a bit loose and the numbers jump a little as my apparatus is not so good.

I will have an update tomorrow... Or late tonight

[JustinTime]

LTMNO, did you decide to go with 6pos switch or is the 'skipped' an dummy position and you'll go with 5pos and five resistors?

[LTMNO]

To All, The solution testing is finalized. I was able to get the right positions I desired with 6 Resistors. In essense, I am replacing the Trim-Pots with Resistors and I am receiving very accurate results. These Resistors are acting as Voltage Dividers and I have increased the values of the Resistors to ratio as to not put excessive Load on the Radio Regulator( credit goes to JHSA for increasing Resistors Values by Ratio ).

Here are the results and I think you will be happy...

Results and Wiring Diagram

Important to note: When you calibrate the your radio with this solution. You need to make sure that you have set your Mid Point to the Center Position. This way the Configuration of your Mode Selections is not affected. Ever!!!

Now that I got this all working on my Testing Board, I am going to solder it up and put it back in the radio. I will in time work on a PCB and perhaps with SMD resistors. I think that would be cool so that it could fit right on top of the Switch with lots of room to add your LED Solution.

Enjoy.

[jhsa]

HEY BEER TIME!!!
You can make a little pcb and also solder the switch on it..
Guys, believe me, this guy didn't rest until he nailed this.. Hands up..

João

[LTMNO]

Ha... Thanks Jhsa....
Just finished the polished Wire Diagram.... Will update the PDF and 1st post.

[JustinTime]

LTMNO, isn't the 1k for the leds kind of high? Especially if you use the 5v? I made a back-light mod for my DX6i transmitter and the resistor that comes with the back-light kit, the one we also use for the Turnigy tx, is 470r or so. I had to put another one in parallel to lower the value because the light was too dim. I brought it down to about 270r and it was much better. The DX6i uses about 6v depending if you use NiCads or Alkaline.

[LTMNO]

Hi. Nope. It's just right. It's very bright.

[jhsa]

It depends on the type of LEDs you use.. different voltages.

[LTMNO]

Okay, I have finally, finally finalized the PCB Design and layout.
Not that anyone is really following this and or will try to do this... But I am building mine today.
This should work just fine. I will post my results later today or tomorrow.

The PCB

The Placements of Resistors

The Mirrored PCB in case you do the Iron-On-Way

Don't forget when you print this image out to make sure you set your Scale to 100% in your printer preview screen.

Stay tuned...

Pino

[JustinTime]

Great, LTMNO, tomorrow I'll be ordering the switch and the resistors. I'll be using leds with 2.2V Voltage - Forward (Vf). Will the 1k resistor be OK for it? Also, can you please mark which resistor goes where on you PCB layout?

[LTMNO]

Ignore this post.

[Helle]

Hy

i think there is a much simpler solution for the Resistor, Volt, %, us calkulation
for 5 or 6 Steps for a Poti replacement.

Helle

[LTMNO]

Hy

i think there is a much simpler solution for the Resistor, Volt, %, us calkulation
for 5 or 6 Steps for a Poti replacement.

Helle

Hi. Could you translate?

[Helle]

Hy,

well,
now I set a later Version of this German Example

but there are only the last 2 or 3 Sentences important to generate symmetric 5 or 6 steps-switch for Poti-replacement
look at Zusammenfassung:

Helle

[LTMNO]

Here is the Document Translated....

Translated Document.pdf

(66.04 KiB) Downloaded 250 times

Thanks for your post... very interesting read... actually the voltage components are something I found out be measuring voltage at increment steps in the Pot at -100/-50/0/+50/+100. I have that captured in a previous post.

I continue to believe the 5 POS is the better option for calibration reasons of the radio as you have a Mid-Point to calibrate with at 1500us.

I am not an electrical engineer but a hack at best... but I have smart friends like JHSA and from my understanding the reason we would want to increase the Resistance from lower values is the load it will put on the Voltage Regulator in the Radio. I think it is only 100ma and the lower Resistance could strain the circuit.

Also, from others that have researched this that the logical values off each gate/step is not the actual for some specific reason on how the radio handles the POT. That is why a Variable TrimPot or calculated Resistor Values is what is needed. Here is a QUOTE from another who has that reason...

[tab=30]Mathematically it's easy to calculate the needed resistors, because these are steady steps, and could use the same value resistors.
BUT IN PRACTICE my testing have shown that the resistance scale is not totally linear with the pwm values.
the reason is quite simple - the radio seem to use some resistor on the incoming +5v rail to the voltage divider (the pot trim) - to limit the current going to the ADC reading chip when the pot is set to full 5v side.
thus the center of the pot (or other resistor) won't give the center of the ADC reading needed.
at least that is what i found with the Turnigy 9x which is very popular. i believe other radios are behaving similar.

I have perfected the values for my T9X radio to be right on if not very close by (-/+) 5us. That is pretty good from my standards.

I guess I am not understanding what the simpler solution is from your post. Could you clarify?

Thanks in advance,

Pino (LTMNO)