Show me voltage divider with real pictures. So, I can see real comonents. Those black and white pictures that most of people find it in Google does not tell me a lot.
polymorph:
I don't understand what that schematic is supposed to do. The top rotary encoder will short the 5V to ground, burning something up. Any rotary encoder contact connected will cause a zero, disabling input from any other rotary encoder contact. All open will cause 5V.Are you trying to connect those as a voltage divider?
I mentioned that I will use ONE!!! rotary encoder at each time. NOT several together.
Or do I really need 40 analog inputs ? Therefore, WHERE TO FIND ?
Here's the explaination you should understanding: Can you use TWO different computers together as ONE person in two ROOMS ?
I suggest you marshal your thoughts, think about what you are trying to do. Write that down in a clear description in one message and post it in a new thread.
Please resize your schematics. They don't need to be that large, it makes it difficult to look at them.
I will do that! Thank you for the compliment.
It will be ALOT of wiring, but sure, I will do.
Well... I am not compentent to expressing in words.
1.
I am will use ONE rotary encoder each time.
2.
They shall just use ONE PWM port to share with. If I use many pins, which is unnecessary, that I will need ALOT of chips to have pins with which waste pins when I can use many rotary encoders to share with.
3.
So I need to set up many resistors, that's what I am always trying to do.
4.
That should be fine. Otherwise, why ?
That's what I want to build such prototype.
Similar as the keyboard port that share just one pin but!!! not use more than one key each time. A keyboard can combine many keys each time which I will not use this method but just one key each time.
Search after "analogue keypad" such as: Redirect Notice
If I'm guessing right, it seems that you want to connect 20 rotary encoder switches in a series configuration (not matrix configuration) to an Arduino, where only one encoder will be used at a time.
It looks like the information at this web page has mostly everything you've been trying to describe, except that you're not interested in the matrix layout.
I think using multiplexor or analog switch ICs would be very useful.
These are the through-hole types available at Digi-Key.
Now I am looking after this explanation. Thank you.
Hmm... First, I will trying with four rotary encoders that I have mentioned as a prototype.
I studied at the images in Google search, now I understood what the voltage divider is. Now I am trying to make schematic.
Now I have uploaded the screen dump; thus, is the schematic correct ?
The bottom of the resistor ladder is connected to 5V. You have the top end connected to A0. The top should go to gnd. The 4 switches should go to A0. Depending on the voltage, you can determine which switch is closed.
Hi, are we talking about 20 rotary switches OR a 20 position rotary switch?
It looks like you want to detect the position of the switch using a resistor divider, fair enough, but if you want 20 rotary switches, you can't just series them all together and still use one input to read them individually.
The basic lack of electronics ohms, volts, watts and amps, along with the reaction from a request to your uncle seems to me that you may be out of your depth, electronic theory wise.
The OP seems to be drawning only one input application, do we have a basic language failure to communicate.
Qwseyvnd can I ask you what is your native language?
(Lets make google translate work here guys.)
Tom...... 
I do not understand this.
A normal incremental rotary encoder have non, one or the other or both switches closed.
The circuit described looks as it needs only a momentary puls when rotated.
Look at the truth tabel attached.
If you turn encoder 1-19 so both switches are closed, encoder 20 looks as it is no 1 ???
pelle
TomGeorge:
Hi, are we talking about 20 rotary switches OR a 20 position rotary switch?
Qwseyvnd can I ask you what is your native language?
(Lets make google translate work here guys.)Tom......
20 rotary switches.
When I am using my third language english, the words and sentences makes very little sense to my nerves; for example, if some write that something weird happens, I do not react.
OK, now I am writing my native language in Norwegian.
Først, 10 forskjellige koordinatpunkt for hver punkt der fly skal passere i rekkefølge fra #1 til #10 med X og Y koordinat i SID or STAR som dere ser i moderne fly system. For å spare antall I/O, ingen vits å bruke mer enn èn rotasjon av 10 stk X og 10 stk Y fordi jeg har kun to hender å bruke med eller en mus og for å spare antall I/O pinner. Denne hjemme cockpit (Iljushin 62) som jeg vil lage er basert fra seksti tallet da flyet ble helt ferdig i 1967. Så jeg vil lage 10 stk koordinatkart, da blir det 20 stk X og Y rotasjon encoder. En Koordinatpunkt har maks 200 km radius fra origo fra flyplass, eller f.eks en sted for GO-KR panel i navigasjonspanel. Hvis du prøver PT Il-62M addon for Microsoft Flight Simulator 2004, da forstår dere hva jeg mener. Jeg har ikke tenkt å bruke flere rotasjon encoder samtidig til å lese dataverdi.
Det jeg prøver er å programmere sånn at X-Plane simulator leser inn kilometer verdi per gang X eller Y av 10 stk koordinatpunkt. Forestill dere at jeg har bare èn datamus å velge 20 stk. Lignende forklaring: èn pekefinger å velge av 20 stk knapper. La oss si jeg bruker 20 stk spørsmåler å stille men har bare en valg per gang. Det jeg vil gjøre er at Arduino kort skal vite hvilken rotasjon encoder jeg har rotert og hvilken vei. Derfor jeg har prøvd å forklare dere dette. Datamaskiner fra seksti tallet er simpel når det gjelder antall stykker inn og ut pinner i forhold til idag som bruker kanskje 2000 pins.
Forestill dere at en datamaskin som kjører kanskje på 4-bits 4 MHz, så sånne datamaskiner sløser ikke bort med mange inn og utganger.
That is this I am looking for
http://forum.arduino.cc/index.php/topic,8558.0.html
but with rotary encoders.
Imagine a microcontroller has just one ground pin, one 5v pin, 1-2 I/O pins and I have eight rotary encoders to connect; then, programming it to read which rotary encoder that I have rotated in clock or opposite. Try that.
Now, do you understood what I am trying to explaining ?
I answer qwseyvnd i Swedish.
Från ditt grannland svarar jag på svenska.
Jag såg den tråd du hänvisar till MEN det är skillnad på momentana knappar och rotationsencoders.
De vanliga enkodrarna kan ha båda switcharna öppna, den ena eller den andra sluten eller båda slutna.
Man kan lämna enkoder i 3 av 4 lägen och den kommer att ge ut signal
Vad jag förstår så behöver du en enkoder som bara ger en kort puls som trycknapparna du länkar till och då fungerar din koppling att känna av en spänning.
Det kanske finns sådana enkodrar men inget jag hört talas om. Om du har enkodrar så lägg en länk så får vi andra titta på databladet.
Pelle
http://www.segor.de/#Q%3DPEC11-4215K-S0024%26M%3D1
I have this.
Here's datasheet
Now, do you understood what I am trying to explaining ?
I took a quick look - it seems like an approach that doubles the resistance value at each node so that the voltage reading for each button will be spaced more equally. Note that here, the resistor required for button20 (encoder20) would be greater than 100 megohm. You're limited to using fewer buttons (encoders) and the signal would be sensitive to noise and have poor stability.
I wonder if you used a straight voltage divider approach, where 20 X 220 ohm resistors are connected in series giving 4.4K total and 20 equal voltage steps, connected as suggested here.
You could test for button presses (encoder signal) by using small ranges in your code with gaps in between. Also, the signal would be strong and more stable.
I'm not sure at this point how to adapt rotary encoder switches to this. I think you would need to monitor both outputs of the encoders (using 2 Arduino input pins) and use 2 separate resistive voltage dividers (one divider for each encoder bit). Then determining the encoder# and decoding the 2 signals could be done in software (Arduino).