Using Griffin Powermate as a scratch controller

[Colonel_Moutarde]

I am looking for a simple way to use a rotary encoder to scratch thru a looping audio file. I have a Powermate and a Shuttle contour in hands, but both are only emulating clics or mouse movements, resulting in shattered audio playouts. I need a nice and clean output as if I were rotating a turntable by hand, both directions. Does anybody succeeded in such a project ? Or do I have to look to DJ turntable interfaces as Numark or Pioneer ? Anybody had success with this kind of device interfaced with Izzy ?

Thanks,

Marc

[Fred]

You can use arduino and a rotary encoder if you want a clean interface. I also have a novation nocturn, this has rotary encoders that can be reconfigured as continuous.

[Skulpture]

I have a power-mate and it's pretty cool - but a bit awkward to interpret the MIDI messages. I need to look at it again to see what is possible.

[gavspav]

I used a DJ Hero Controller + Arduino. Cheap and cheerful.

[m_theater]

hi marc,

i would try to convert the sound into a movie and fiddle around with the speed setting

this shall give you a much smoother playback then selecting the position

interfacing the devices is the second step

i could imagine a counter in a short timer

count modifications(rotation of your knob) modify this to speed

reset speed after xxx seconds

good luck

best clemens

[Colonel_Moutarde]

Thanks for all your suggestions. The thing will be buried deep into a museum exhibit, so no need to have a nice and neat look. The speed control of a movie seems to be the best option for smooth playback. I haven't set any hardware yet to make some tests, but I will very soon. As the installation must last about 6 month unmanned, it has to be as simple and sturdy as possible, with no manual config to do on daily startup.

[Colonel_Moutarde]

Just thought: Using a DC motor to generate voltage proportional to the rotation speed, and turn it to data to be read by Izzy. I just need something to catch direction of rotation, or offset the output voltage with a bunch of transistors.

[Skulpture]

Had a little test... edad00-power-mate.izz

[eight]

https://www.youtube.com/watch?v=HQuLZHsGZdI

--8

[m_theater]

sculptures test motivated me to try how the speed approach could sound like

so here it is

without the power mate aded two buttons for left and right turn

and a toogle to switch between the position and speed way

b0f295-power-mate_2.izz

[Colonel_Moutarde]

I think I will forget the Powermate approach, mainly for mechanical reasons. I need a really sturdy and reliable setup.

I've made some tests with an Arduino sending me MIDI pitch messages according to the speed of a DC motor and two different velocity according to the direction (actually, I simulate it with a pot and a toggle switch). Hardware side is fine and everything is OK when playing forward, from 0 to around 300% which is the max speed I want to achieve. But backward play out has hiccups. So I created a backward file which I sync to the other file and switch from one to the other according to the direction. But sending direct position makes my ears bleed ! 

So I've added a lookup when direction is changed and feed the actual position to the muted player only at this time. 

It works fine but as I am quite a rookie with Izzy, advises for better programming are welcome !

b21488-ko-scratch.izz