TK.

MIDIbox KB

182 posts in this topic

hi!
impossible to calibrate the joystick. my modwell-min: 50 max: 110.
there any solution flow min:

 

thank!

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It seems that your joystick has a very reduced range - are you sure that this isn't a mechanical issue?

Or maybe Vd/Vs (3.3V and Ground) are not connected properly?

 

Best Regards, Thorsten.

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hi!  thanks for the reply.

The joystick and new, bought as a spare Roland VA76.

it self there are joysticks that are good for this project tell me what they are.
I like this joystick roland, but itself is not good, I delete.

 

best regards, Silviu

Edited by folly

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It's still unknown, if you've connected the joystick wrongly or not.

 

Which voltages (against ground) do you measure at the wiper (middle pin) if the pot is in max and min position?

 

And do you know the resistance of the pot?

 

Best Regards, Thorsten.

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This is indeed a very reduced voltage range. Scaling over such a small range would result into jitter issues -> forget this joystick. :-(

Maybe Lars aka. rvlt can give you a hint for suitable pitch/modwheels

 

Best Regards, Thorsten.

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It is possible to scale and offset the signal from your pot wiper to the ADC input with a single opamp and some resistors.

There are cheap dual and quad op amps that output down to 0V. You would use +5V for the op amp supply.

I guess you would only bother going down this path if *really* like the particular modwheel/pitchbender/joystick and want to make it work with full resolution.

I can post more details if there is any interest.

(*not advised for total newbies, not too difficult though, if you've built electronic circuits on matrix board before)

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thanks Duggle. accept any information. there are no problems with the construction of various electronic, I have built many electronic circuits.

thank!

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I've put the description, info, and example in it'd own thread: 

(Folly, I've used your case in the examples, so lets us know of your success (or problems) if you try it!)

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I ripped my wheels off an old miditech-keyboard, and another one from a m-audio oxygen8 V1 (was the same wheel assembly on both). Other than that I only know Doepfer who sell wheel / joystick combos:

 

Doepfer - Accessories

 

I once repaired a CME keyboard which had a special potentiometer for the pitch/mod wheels, it was from "Alpha" and had 90° printed on it. With these you get the full potentiometer range by only turning it 90° (centered). You could only get it from CME support for 10,-  Euro / each. Pretty expensive. 

 

Cheers

Lars

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Ciao All!

I am building my own digital organ with three Fatar keyboards. I am looking at Midibox KB and it seems quite interesting (I already midified a pedalboard with the PIC core), but it seems it supports scanning only three keyboards. Are there any technical reasons on why I cannot scan more? I would like to try to modify it to support three, even if the scan times slow a bit I think it should not be a big deal (for me at least :) )

 

Thanks!

Rodolfo

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Hi Rodolfo,

 

one of the reason is, that with more keyboards the scan frequency decreases, which results into higher latencies.

And a practical reason is, that the EEPROM dump structure can only store two set of keyboard parameters - fixing this would result into a lot of incompatible changes.

 

However, you could try MIDIbox NG instead, which comes with the same keyboard driver.

In MBNG I could easily increase the number of keyboards (in one of the next versions), because parameters are stored in a configuration file on SD Card.

See also the kb_*.ngc examples under: http://svnmios.midibox.org/listing.php?repname=svn.mios32&path=%2Ftrunk%2Fapps%2Fcontrollers%2Fmidibox_ng_v1%2Fcfg%2Ftests%2F

 

The usage of MBNG has another advantage: you can easily add more control elements (like drawbars, etc.)

 

Best Regards, Thorsten.

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A new MIDIbox KB release is available:

 

MIDIbox KB V1.011
~~~~~~~~~~~~~~~~~

   o support for "ain_bandwidth_ms" which allows to reduce the number of generated events
     over time.

   o added "ain_pitchwheel_inverted", "ain_modwheel_inverted", "ain_sustain_inverted"

   o added "ain_sustain_switch", which allows to change between switch and pot behaviour

 

 

Best Regards, Thorsten.

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hello to everyone! does anyone know how you enable the MIDI IN 1 - 2 of MIDIBOXKB?
 

I do routing between MIDI IN 1 to 2 MIDIOUT.
I want to connect midibox64, with 20 potentiometers

Edited by folly

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Please install the new version first:

 

 

 

MIDIbox KB V1.012
~~~~~~~~~~~~~~~~~
 
   o MIDI router configuration now stored in EEPROM
 

 

thereafter enter following commands into the MIOS terminal:

 

set router 1 IN1 all OUT2 all
store 

 

 

Note that you could route IN1 to USB1 in addition with:

 

set router 2 IN1 all USB1 all
store

 

 

 

Up to 16 router nodes are available, you will get an oversight with:

 

 

router

 

 

 

 

Best Regards, Thorsten.

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Thanks TK. now I can start drawing my keyboard.

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As mentioned in a thread (MB_NG) I've tried to connect my expression pedal to the analog ins of the LPC.

 

It seems to work, but I've got jittering values (about cc-value 122 in one direction, 6/7 in the other) . I tried to connect a resistor between 3.3V and the pin on the exp-pedal. Same here. I saw, that there is a "calibration" function in the menu. When I try to calibrate, the monitor gives me a LOT of informations. But I can see no change if I pull down the exp-pedal. At this point the application (or MIOS Studio) hangs and the only thing I can do, is plug off the USB from the computer and restart the application.

Is there a way to manually calibrate the pedal? Because now the monitor says, the min_value of the analog_in is 0 and the max_value is 255.

Edited by FantomXR

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You won't be able to get rid of the jitter, it's caused by the bad analog supply of the LPCXPRESSO.

Since you are using a second core with a MBNG as well, you could use a AINSER8 or AINSER64 based analog input instead -> much better results!

 

Best Regards, Thorsten.

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Hey thorsten, That makes sense. But is there a way to calibrate the exp pedal without a crashing software? :) I want the pedal to go from 0 to 127. Thanks!

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Hey!

Here I've got an old Yamaha DX11 Keyboard. I disassambled the keyboard from the housing and the electronics. I've got the schematics too.

The keyboard is equipped with aftertouch. The aftertouch-strip is connected to two pots. The first one says Gain, the second Offset. These should be there to configure the aftertouch. After that there is a four-pole connector. These pins are described in the schematic with +15, -15, GND, signal.

Am I'm able to use the aftertouch function with this keyboard? I'm not sure, if NG is fast enough to scan the keyboard without a huge latency (like in my P80). How to connect the aftertouch to the core?

 

Thank you very much!

Chris

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Okay, I think, the best way is not to use the ICs on the PCB in my DX11 keyboard.

 

Instead I connected the aftertouch stripe directly to the core. The strip has round about 150Ohm depressed. Pressed it goes to 20-30Ohm. I put J5.A0 of the core on one side of the strip and J5.VS on the other one. I put a 1k resistor between 3.3V and A0. 

 

To get values I can work with, I assigned J5.A0 to a cc-event. I set MIOS in debug mode and set the pinrange in the ngc-file.

 

Now I get jittering values. Depressed I get values between 114-125, by pressing a key it jitters between 0-15. Is the jittering a problem of the AINs of the core? What do you recommend? I don't wanted to build in a AINSER64 just for one controller ;) So if there is another solution, I'd be happy to hear it.

 

//edit: I saw there is a AINSER8. Is this available? Can't find it at AVIShowtech...

Edited by FantomXR

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Instead I connected the aftertouch stripe directly to the core. The strip has round about 150Ohm depressed. Pressed it goes to 20-30Ohm. I put J5.A0 of the core on one side of the strip and J5.VS on the other one. I put a 1k resistor between 3.3V and A0. 

 

To get values I can work with, I assigned J5.A0 to a cc-event. I set MIOS in debug mode and set the pinrange in the ngc-file.

 

Now I get jittering values. Depressed I get values between 114-125, by pressing a key it jitters between 0-15. Is the jittering a problem of the AINs of the core? 

I recommend making sure the analog signal at A0 is right before making any bold decisions.

Can you make a voltage measurement with a multimeter on A0 (and 0V)?

What are the voltage readings when:

  1. not pressed
  2. pressed at the top
  3. pressed in the middle
  4. pressed at the other end

This will provide information to determine the correct value of bias resistor (currently 1k) to give the best voltage range for the ADC.

 

I use the Core ADC for my pitchbender and Mod wheel and it works fine.

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I have no probs with Pitch and Mod too! I use also the core ADC for them... but with aftertouch it's more difficult... I will try, what you suggest.

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I measured:

 

not pressed: 0,43V

top: 0,30-0,33V

middle: 0,13-0,15V

other end: 0,05-0,07V

 

Thank you!

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You'll want the voltage range at A0 to cover approx. 0V to 3.3V to get the best performance (which will be a lot better than what you have now).

Before I suggest specifics:  is there a current or power or voltage limitation on this device (i.e do you have any data or absolute maximum parameters etc)?

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