Is anybody succed using a software trick to use AIN with another value than 0 - 5V ?
i want to use 1.2V to 4.7V instead of classical 0-5V …
in fact i want to use some pots but without using the full rotation …
Any idea ?
Either some software solution (you best ask for that @ MIOS topic or directly to TK - who isn´t here @moment).
Or a hardware solution:
With some OPAmps you can change any voltage to some other voltage (e.g. get the voltage with one OPAmp down by 1.2 Volt and with a second OPAmp factorize it to fit the 5V maximum).
Greetz!
thanks pay_c … but i’ll prefer a soft solution for my double MB64e … i’m tired to solder wires and wires and wires and wires and wires and wires and wires and wires .. 
maybe you can change the vref of the pic adc (don’t know if it’s possible).
What is it for?
I have a similar Question,
I have some Alps 200k pots and wondered how I get them to work on the ain.
Maybe its just a question of adding resistors? so that when the 200k pot is on full deflection the resistance=10k not 200k
Or is it a Mios trick?
Any feedback greatly appreciated!! ;))
i’m making a new control glove .. using 10k pot but without the full course ( i mean nothe full rotation …)
the midi values are from 05 to 119 instead of 01 to 127 …
so i need a software trick to have the full 127 values …
i’m looking in the mios code .. without any result from now …
for mark420 i think you can cheat with different voltage … ( resistor .. post edited … )
MIOS need 0 to 5v … put another voltage ( instead of 5V) and check what you can have on thepot pins … but DO NOT PUT more than 5V on AIN !!
It doesn´t matter what the max resistance is so much, cause you use those pots as voltage dividers. You use them to go from 0 Volt up to 5 Volt.
So the only thing what could happen is jittering. As in 10 k Pots there is a current of appr. 0,5 mA running, there won´t be so much jitter anyhow. But with 200 k´s you only got 0,025 mA (25 uA!!). That´s a little low, this will only work with a very good shielding (which the ALPS faders perhaps have).
I would give it a try, but if it jitters, you got problems…
Greetz!
Ok guys I understand a bit better now.
Well I have to wait a couple of weeks before I can try this out (waiting for parts;(() but I will cross my fingers and hope the noise isnt too bad..
On a related point…The midibox I am making is going to be made from a converted audio mixer u see (hence the good quality pots and faders) and the pots and buttons on the mixer are mounted onto a pcb then mounted with pillars under the face plate.Theres soo much room inside the mixer to fit a core and modules.
I dont want to destroy the audio mixer so i was thinking…if I wire the core’s PSU to the mixers pcb and then take only one wire per pot back to the Ain module by soldering on the pcb cos +5 and 0v would be from the board, and its got a great ground plane!.
Same with the switches on the mixer-its got i think 6 mometry switches and i think 6 latch switches wich i hope i can make into layer buttons to add more switches.
Like the pots i hope to be able to solder the switch wires from the back of the mixers pcb.
I think this would help stop “jitters” thro ground problems?
And also maybe when I get it all working I “maybe” get it to work both as a midibox and then with a throw of a switch it goes back to being a standard (very high quality) audio mixer.
Well, if the pots are from an audio mixer, they are probably logarthmic, and mios should have linear pots.
I think log pots will work but the values you get will not be equally spaced. as for swapping between audio mixer and midibox, i am not sure that this is possible, and if it is it is probably not easy. I think I would keep your very high quality audio mixer as is, and build a seperate MidiBox. If I had a very high quality audio mixer, I wouldn’t go mucking around inside and adding things to its pristine circuitry, but I have never had the pleasure of owning such a mixer. Maybe you could look for a broken mixer on ebay.
Just my thoughts, anyone else got a comment?
oki Gilles it seems to be a very intersting project!! 
I wanted to make some Virtual Reality stuff some times ago, a glove is a good start 
I still plan to make something in opengl… (and I want to build a hemlet too hehe).
Well, the adc of the pic is 10bits max, so you can scale the pot easily I think, need to make some pic asm (or C code ;))
well im kinda lucky…its surplus to requirements (i have two of the same model u see) and very easy to take apart and theres soo much room inside for midibox circuits.
Its also has rackmount brackets so I can make a nice flight case solution so that I can lug it around to clubs etc..
I have found out the model number etc of the pots and heres a link to the data sheets.
http://www3.alps.co.jp/pdf/2004pdf/pdf_e/Potentiometer/Insulated/14_insulated.pdf
I cant see anywhere if they are Log or Lin pots and the part number doesnt suggest anything.
I know for sure that the faders are 10k Linear cos I have crossref them with the Alps site and i can see them there.
I am using it only for Traktor (normally I use the mixer like a traditional mixer with Traktor coming in on two line in channs, I would much preffer to use the mixer as a midi controller because then i can cut down a LOT of mouse and kb activity and you can get a more precise control of parameters with a pot than a kb key..Also its going to help a lot when i am recording demo mixes for promoters/clubs etc.
Mark;)
So? Just measure it out! ;)
Just use some Ohmmeter and put it to the lower end and to the middle pin. If you now move your fader to appr. the middle it should show 100 k (half of 200 k). If it does not and shows something like 60 k or so (less) it´s logarithmic (you can also recognize that if you move the fader - at the beginning the increments are very low and to the end it will be something like 20k or more per millimeter).
Greetz!
TK ? did you experiment some code about non full course faders ?