How to add a 6 position switch to a Futaba 9C

[KK1W]

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Here';s a short, step by step video I did showing how I added a 6 position switch on my Futaba 9C transmitter. Special thanks to Gerry (pheasant plucker) for finding a source for the switches. They are still available on eBay. Any six position switch would work as long as you can fit it in the transmitter. The 9C is pretty crowded in the area where I put mine but it could be installed elsewhere too. Hey, it';s your transmitter - you can do what you want with it, right! 

Here';s the link to the Grayhill switch I used: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=330867536837

A few notes not in the video (actually it';s a slide show, I suck at videos  )

MODIFICATION NOTES

1. You will need five small resistors, 1/8 or 1/4 watt should fit. The value is one fifth the resistance of the pot the switch is replacing. In the case of the Futaba VR(A) is a 10K pot. Divide by five and you get 2000 ohms. This isn';t a standard value, but 1800 and 2200 ohms are OK too. I used 1800 ohm because I had them on hand. It isn';t critical, the most important factor is all five are about the same value.
2. The resistors go in series starting with terminal #1 and ending on terminal #6. It';s a small switch so take your time and it will come out all right.
3. Once the resistors are soldered on to the switch you also need to add three wires. One wire goes to the center terminal of the switch, one to terminal #1 and one to terminal #6.
4. If you use the Greyhill switch it is an 8 position switch. Included are pins to drop in holes on the switch to stop the rotation. See the instructions on the eBay page for more detail.
5. This modification IS NOT REVERSIBLE! Please be sure you';re comfortable with doing the work. It isn';t hard but you need decent soldering ability, a steady hand and a little bit of familiarity working on circuit boards. The photos show VR(A) removed from the circuit board before cutting. I did this to double check the traces. If I did it again I would just cut the board off next to VR(A) and be done with it - much quicker.
6. When soldering the wires to the circuit board the only important wire is the one from the center terminal (common) of the switch. It must go to the indicated trace. The other two wires can be swapped - if the switch works backward just reverse the channel in the TX. If you prefer to splice into the wires going to the circuit board here';s the color code:

Brown -> Center terminal of the switch
White -> Terminal #1 of the switch
Gray -> Terminal #6 of the switch

Setting up the transmitter

1. Assign VR(A) to channel 5
2. Connect your FC (I';m using an APM2.5) to Mission Planner
3. Go to the Config screen and choose Calibrate Radio.
4. Turn your new knob and watch Channel 5. If it is backwards to the way you want it to work reverse channel 5 in the TX
5. Turn the knob to position #1 and note the pulse width. It should be under 1230. If it isn';t change the endpoint until it is.
6. Turn the knob to position #6 and note the pulse width. It should be over 1750. If it isn';t change the endpoint until it is.
7. Now go to the Flight Mode screen and check that each numbered position of the switch lights the corresponding box. Make a note of the actual pulse width and if it is really close to either end of the recommended range you may want to tweak the endpoints a bit. Here';s where mine ended up:

Mode 1 = 1086
Mode 2 = 1257
Mode 3 = 1432
Mode 4 = 1524
Mode 5 = 1689
Mode 6 = 1914

Hey, you';re done!  Go out and celebrate your handiwork 

Here';s the video slideshow. I hope it is clear enough to follow. Please let me know any comments or what I could have done to make it easier to follow. This is my first (and maybe last  ::)) attempt at some type of instructional video. Hope you like it!

http://youtu.be/fJECMS9w4OE

[firey1]

another option im looking at for my TX

http://www.ebay.com/itm/UNIVERSAL-Mode-switch-6-POSITIONS-ArduCopter-ArduPilot-READYMADE-/110952477520?pt=US_Radio_Control_Control_Line&hash=item19d5487350

[KK1W]

Firey1,

That is a good solution too. I like the way the pots are pulled out on a cable so you can fit them most anywhere there is some empty space.  Having the ability to tweak the four intermediate settings is nice too. The only thing I would be cautious of is the size of the switch itself. Double checking your TX mounting possibilities first would be a good thing to do before ordering.

My biggest problem is I now have six flight modes but only have progressed to ';stable'; so far  - but the weather is getting better over here, finally ;D

[firey1]

cheers yeah i have the 9xr so should fit ok on that
ive goten to stab / alt hold / loiter and trying to get up the courage to try RTL

[stubtoe]

Hello KK1W

Preface:-
     I have a  Specktrum DX9 and have modded it to stop an intermittant  battery discharge problem - put a switch in battery lead - via RCG I';m told it is an FET fault but ';they'; won';t tell the location of it. As you may know Horizon Hobbys have pulled out of UK and are now located in Germany causing MEGGA prob';s with servicing Spektrum Tx';s, Rx';s etc 
     So I am raising from the dead my trusty FF9/9C Tx just in case the DX9 goes tits up   (am not going to sending it to Gernany)   and in doing so am in the process of fiitting the 6Pos sw.
   AH !?... you may ask why not get a Taranis, the latency is  much better, by far,  but at three score and ten + years I have got me own built in latency to start with and a little more aint gonna be a problem. But eventually may get one.

Any way after all the above bumf my Question is can the Taranis 6position encoder switch be used which has SMT resisters on a tiny PCB, see   https://www.youtube.com/watch?v=Ts0EzeJsoNc have ordered one from Banggood but will take a couple of weeks, damn...joe       

[KK1W]

Not knowing the resistance of the pots in the Taranis it';s difficult to answer the question. If it';s somewhere near what the Futaba 9C (10K Ohms) it should work but you may have to play around with end points and curves to get it where you need it. This article seems to suggest the Taranis pot is very similar in value to the 9C ]http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A428082&commentId=705844%3AComment%3A1126231]. Maybe someone with Taranis experience will comment on the value of the variable controls?

If the Taranis is way different, lik 5K 0r 20K Ohms you might need to brush up on your SMD soldering skills and swap out the resistors 

Good luck,

Jim

[pheasant_plucker]

Unfortunately I don';t think it will work. I believe the Taranis 6 position switch is a rotary encoder not a six position rotary switch in the nornal sense. it sends a binary code to the transmitter.

Gerry

[stubtoe]

Hi Fella';s
              On receipt of the Taranis switched resistance/encoder I will give it a good poking with my Fluke and report back - thanks...joe