Tempo fader encoder design

[djkrugger]

Hi guys, i'm still working on my project, i've been working mainly in the arduino code which is not that interesting, but i have the base for the code worked up i'll be using 26 rotary encoders 80 buttons &64 leds, split in 2 identical units to sit to each side of the mixer. One particular design obstacle i've seen in most of the DIY controllers is the tempo control, since it varies automatically when you use the "sync" feature so using an analog potentiometer with "soft takeover" seems to be the most popular solution, but trying to correct the tempo "on the fly" with "soft takeover" on leads to disaster. So i got the idea of using an encoder but, i found different problems, rotary encoders for tempo are awful, linear encoders have finite motion (end are expensive as hell!) touch strips give an absolute value (if tempo is in -1 position and you touch +6, it will jump up to +6!) and lack tactile feedback.
So i came with this design, please fell free to make any suggestion and use it for you project.
The rotary encoder would be one without detents and the belt is a geared belt.


pulleys

Pulleys

Belts

Frame

[zestoi]

touch strips give an absolute value (if tempo is in -1 position and you touch +6, it will jump up to +6!) and lack tactile feedback.

you could convert the absolute value into a relative message too in the same way the (awesome imho) scs.3d does. in that mode i dont see the lack of tactile feedback an issue at all.

[Mudo]

I have 2 units of this. Do you find it useful or interesting? Let's talk...

http://www.youtube.com/watch?v=WHaSLoNxfBY

Guy on yellow tshirt not included (but I could get sold if the $$$ is generous lol)

[djkrugger]

That's very cool, but the problem i see is what i said before, if you have the tempo set, let's say, in -5 % and you touch the strip in the +8% position, the tempo will jump instantly, not very "mix friendly", IMHO.

[djkrugger]

Look at 02:01, see what i mean?

[zestoi]

That's very cool, but the problem i see is what i said before, if you have the tempo set, let's say, in -5 % and you touch the strip in the +8% position, the tempo will jump instantly, not very "mix friendly", IMHO.

that's not true at all. if your firmware (or other middleware app) converts the absolute midi message into a relative encoder-style one based one based on previous movements and timestamps etc.

e.g: the scs.3d will send out a note on when you touch the strip, then an absolute cc (0-127) as you move *and* a relative cc (63 or 64 (ish, depends on how fast u move)) like an encoder before sending out a note off when you release the touch strip.

[zestoi]

Look at 02:01, see what i mean?

at 2:01 in the video he's demonstrating the circular area using the absolute midi messages. each strip sends out an absolute *and* relative message and its up to you (or traktor) which of those you want to use.

for what you want to do, adjusting pitch, you'd ignore the absolute message and just map the relative one.

edit: u posted the vid while i was writing my 1st reply - hence this 2nd one.

[zestoi]

have a look at that video at 3:20, there he demonstrates the pitch slider thats working in relative mode. in reality all the sliders send out absolute and relative messages for each motion, he's using darouter there (that i dont use) that does some extra translation of own on top.

[kostis12345]

Have you considered motorized faders? Yeah they are expensive but they could work.
Another thing you could try is to replicate the faders of the V7. When switching from one deck to the other the tempo fader stops working until you get it to the position of Deck 2.
If the fader of Deck A is below the one of Deck B an arrow pointing up lights up and the other way around. You would need however to find a way to send the BPM/+- pitch from Traktor to your Controller

[djkrugger]

have a look at that video at 3:20, there he demonstrates the pitch slider thats working in relative mode

Yeah, that's cool but rotary encoders are easier to implement, although the mechanical disadvantages counterweight that, i might give the resistive strips a try.