Need Help with Controll-Device for Finetuning

  • Q&A Forum
  • Need Help with Controll-Device for Finetuning

I think this is a challenge for Bome MT…


I want to built a big Touchcontroller for Light and sound…

One site is to Calibrate my Movingheads to the current Location…..

So with the Button I call the Vallue to Calibrate and then the slider shows me the actuall used value….

this is very coarse and so i want to use the Jog wheel to remote the slider for fine tuning

the Jog Wheel is sending Controller from 0-127 and then it beginns on 0 again


one turn of the Jog shold be +1  or -1 on the slider value….

can you give me a tip what’s the best way to do this

Marked as spam
Posted by (Q&A Forum: 2, Answers: 6)
February 2, 2019 10:09 am

My Lightsoftware is Lightjams and there I have a value 255DMX mapped to 127 MIDI

thats coarse …..

but internal Lightjams is working in % 100,00 so I am a little bit confused how to bring a linear mapping with using fractional digits also to lightjams

( at February 2, 2019 10:42 am)

Hi, let me make sure I understand what you are asking.

1) You have a touch control surface that you have created. The values might be a random value.
2) You want to press a button and move the slider. When the button is pressed you want to track the slider value and capture that value as a global variable (for future use).
3) You want to use a jog wheel to fine tune the slider value even further.
4) You want the value you track with your slider to be 0-255 instead of 0-127

My questions are:
1) Is the slider currently only 0-127 (which is the standard for MIDI)?
2) At some point I assume you will send the slider value to some other device. What other device and how do you intend to send it? If MIDI CC again 0-127 is the best you will get unless the destination can receive 14 bit MIDI CC value (0-16383) or pitch bend of -8192 to 8191.

In summary, we can scale the value of the stored value of the slider but if the slider only has 128 step values, you will not be able to use it for finer granularity than that.

What we could do is use the slider or knob to send only increment/decrement values so that internally you can store things at higher granularity, but when you knob reaches the end of it’s range, we would need to device a way to disable the value capture so you can move it to the other end of it’s range and continue moving it.

( at February 2, 2019 5:19 pm)
Private answer

Here is a tutorial that shows how to map an absolute MIDI value to relative. This is the technique you would use for your jog wheel to output relative values (like most jog wheels do).


The below tutorial shows you how to scale a value. By scaling I mean change the MIDI range of incoming vs outgoing. This is the technique you would use to set up outgoing range of 256 (however you would not get better precision than a 128 MIDI controller would have. However if you lighting application supports pitch bend or 14 bit controller input, we could easily scale down for 16384 to 256.


Marked as spam
Posted by (Q&A Forum: 36, Answers: 3116)
February 2, 2019 5:37 pm
Thanks for your help….because I am not a Math.-Professional What I think after long reading, learning and testing and Headache….. It’s a simple thing when I see what means 14 bit … the last 7bits only represents 128 Values not more ….so I only have to switch the slidervalue +1 when Jogwheel goes 128>>>0 and -1 when 0 >>>> 128…… will test it. For Use the slider values in Lightjams I have got a crazy formula from the Lightjams-GOD Mathieu that directly brings the two values to a 100,00% Value….I can do this directly in Lightjams. Cheers Jürgen
( at February 2, 2019 7:34 pm)

Yes, however values in Bome MIDI Translator are 32 bit integer so a -1 is really represented in as FFFFFFFF in Hex. If you want to represent -1 in 7 bit signed values it would be 7F in Hex.
To represent -1 in a 14 bit signed integer it would be 3FFF Hex.
These other representations are only important to any device you are sending numerical information to and the way they interpret the values. Internally everything is 32 bit signed integer.

In summary, if the external device understand 7 bit, you send 7F as a -1. If the external device understands 14 bit then you send 3FFF to represent -1.

It is entirely possible that this may be difficult for you so let me know if you get stuck by showing your current project file and where you are stuck.

Steve Caldwell
Bome Q and A Moderator and
Independent Bome Consultant/Specialist

( at February 2, 2019 7:47 pm)