USA Part Number for flight control switches?

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drigotti
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USA Part Number for flight control switches?

Post by drigotti »

I'm seriously considering building from parts a 6 channel reed system using Phil's encoder stuff. I've sourced a 7" by 5" by 3" aluminum case (Bud CU-3008-A) for it.
I'm looking for a USA supplied part number for the flight control switches. I "assume" these are momentary contact types? I see some discussion on guitar switches....BUT these don't seem to be self centering?
Help me understand and source these.
Thank You
Dave Rigotti
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Martin
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Re: USA Part Number for flight control switches?

Post by Martin »

The guitar switches are self centering, once modified. Modifying them doesn't need any special tools or equipment - you just undo the fasteners to take them apart, bend/straighten some of the wafers slightly, and then reassemble in a different order - it's fairly obvious when you've got the parts in front of you, and after doing the first two or three and getting the knack, the others will only take a couple of minutes each to modify.
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ozrs
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Re: USA Part Number for flight control switches?

Post by ozrs »

The original switches were mostly the "Switchcraft" brand - still available on ebay, but expensive:

https://www.ebay.com/sch/i.html?_from=R ... itleDesc=0

cheap Chinese versions are readily available:

https://www.ebay.com/sch/i.html?_from=R ... itleDesc=0
Richard
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tiptipflyer
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Re: USA Part Number for flight control switches?

Post by tiptipflyer »

These chinese switches are real cheap:

https://de.aliexpress.com/wholesale?cat ... tar+switch

They come in different colors and are suitable for conversion. I use them in various reed transmitters.
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drigotti
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Re: USA Part Number for flight control switches?

Post by drigotti »

Thanks for all the great feedback. I know a bit more now.....making me dangerous!
Another question please.......
Do the "long" switches have a "softer" feel compared to the short ones?
Anybody have experience on this?

Dave Rigotti
Dave Rigotti
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drigotti
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Re: USA Part Number for flight control switches?

Post by drigotti »

Shall I also assume these guitar switches are "3 way"?
Like this:
https://www.ebay.com/itm/Switchcraft-St ... 1438.l2649
Dave Rigotti
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PaulJ
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Re: USA Part Number for flight control switches?

Post by PaulJ »

Dave, yes the long switches have a softer feel and the one you show in your link will be fine. However as Martin pointed out, you have to modify them......... The switches are simply a sandwich of leaves and insulating spacers held together by the two bolts at the bottom. As supplied, guitar switches are "3-way" and "latch" when operated so having disassembled the whole caboodle, you have to straighten out the two bent leaves so it won't latch and then re-assemble in what will be an obvious order.

My understanding of these things is somewhat limited but as I understand it, Phil's "Reeduino" works by emulating the stick pots on a propo unit. So when you operate the switch, instead of going progessively from it's centre position, the servo goes instanly to full travel. To do this you put a fixed value resistor both sides between the centre contact and the and the "make" contact (no doubt Phil will correct me if this is wrong). My switches are a different pattern to the ones you showed but the principle is the same, hopefully this pic will clarify things.......
Guitar switch.jpg
Paul
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drigotti
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Re: USA Part Number for flight control switches?

Post by drigotti »

Thanks Paul! The description and photo helps a lot!

Dave Rigotti
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Phil_G
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Re: USA Part Number for flight control switches?

Post by Phil_G »

PaulJ wrote: 02 Nov 2018, 09:11My understanding of these things is somewhat limited but as I understand it, Phil's "Reeduino" works by emulating the stick pots on a propo unit. So when you operate the switch, instead of going progressively from it's centre position, the servo goes instantly to full travel.
Absolutely not Paul, sorry I dont want to come across all stern and finger-waggy but thats not at all how its done and I hope you dont mind if I 'nip this in the bud' :D
The only reason for using analogue inputs with the resistors centre-biasing is to enable 3 'digital' positions to be read from one input pin. It makes the cabling easier and its more economical on processor input pins. The toggle positions are not in any way linked to servo outputs, or to the resistor values.
Each input is quantised to 3 states: 'left toggle', 'right toggle' or 'neither'. To do this I use just the 2 most-significant bits of the ADC, which are translated as:

00=toggle thrown one way, signal line less than 1/4 rail, typically at ground 0v
01 or 10 =toggle at neutral, signal line is between a quarter to three-quarters rail, typically around half (2.5v)
11=toggle thrown the other way, signal line above 3/4 rail, typically the full 5v

Anything from 1/4 to 3/4 rail is seen as the toggle at neutral, this completely eliminates any resistor tolerances.

All the servo positioning is done from subsequent processing of 'target values' derived from several sources - the current position, servo-slow, trims, ATV and the various mixes - its nothing to do with the precise voltages read on the analogue inputs as it would be with a propo stick pot.
The old PIC Reeds encoders (the 12 & Tiny6) use exactly the same technique. Its important to me because replacing sticks pots with fixed resistors on a propo encoder would a very simple but poor way of emulating reeds, and I dont want people to think the Reeduino or PICs use such a cheap & nasty option :D

All this can be demonstrated by using unequal resistors - normally they are equal but unimportant in value, say 4k7, 5k6, 10k, etc. Try deliberately biassing the toggle slightly one way, replacing the two 10k's with an 11k and a 9k. That would offset the neutral, right? No, it doesnt, nothing changes because the resulting bias still falls within the 'neutral toggle' band of 1/4 to 3/4 rail - neutral toggle is a digital switch status, and neutral servo is the result of lots of unrelated calculations Image

Hope we're all ok with this, bit of a rant, sorry again! :D

Re toggles, here you go Dave:

http://mode-zero.uk/viewtopic.php?f=26&t=126&p=302

Cheers
Phil
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PaulJ
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Re: USA Part Number for flight control switches?

Post by PaulJ »

Oops! Sorry Phil :oops: Well, I did say my understanding of these things was somewhat limited! :roll: However it shows how foolproof your instructions are because even though I misunderstood the reasoning behind what I was doing, it still works and hopefully my picture will have helped! ;)

Paul
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