Fietspomp

'Seventeen' a 17 button midicontroller with LDR / light sensors

9 posts in this topic

I have designed a very simple midi controller with 17 inputs some of which are LDR. It's use would be as a controller for VJ software. It features 15 pots and an lcd screen with two buttons, to view and change the current preset. As this is my first midibox project, I would appreciate any design comments or suggestions!

midi-controller-design.jpg

I recon I need:

1 x 32-bit core module or 8-bit not sure

2 x AIN module (for 12 x 2 = 24 analogue inputs)

1 x 16x2 LCD module

1 x Bankstick

1 x power adapter

2 x push button

1 x power button

All at 10kOhm

5 x slide pot (50mm travel)

5 x turn pot

5 x ldr light sensor

UPDATE: corrected usb symbol to match usb-b on the core32 module

Edited by Fietspomp

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Perhaps trivially, you've drawn the USB as a host connection.

How do you plan to use the LDR's in the context of VJ'ing? (can think of interesting feedback setups with Midi controlled lights!)

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As a host? I thought I just drew USB as it looks in the real world I guess it looks like a sata connection (if that's what you're referring to) too. Incidentally it is the wrong type anyway, I need to change it to usb connector type B which is what core32 module has.

The plan for the ldr's was to have a more organic way too change values, by 'feel' rather than pin point precision dial. It also allows to control many different parameters at once and quickly consecutively. Beyond this I want to implement a gesture system in the future. Since I am building my VJ software from scratch (in OF/c++) I can accommodate this kind of input.

The feedback idea hadn't crossed my mind but it is nice idea, mounting an led 'belt' or similar on top of the controller with delayed ldr data lighting them up would indeed yield some sweet results.

Fietspomp

Edited by Fietspomp

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As a host? I thought I just drew USB as it looks in the real world I guess it looks like a sata connection (if that's what you're referring to) too. Incidentally it is the wrong type anyway, I need to change it to usb connector type B which is what core32 module has.

Indeed, you seem to understand that you wont be able to plug your camera or smartphone into the midibox via USB (..yet!)

Actually a bank of LDR's as a straight up controller is a fantastic idea. Especially for simultaneous control of multiple params, as you say. I have a novation keyboard with a touchpad like a notebook PC. You can assign 2 CC parameters per axis (they crossfade in opposite directions, but also respond to multiple touches, a bit like mutlitouch) for both X and Y directions. It works really,really well. Explore all sorts of modulations just by moving the finger in a 2D "map". An arrangement of LDRs has even less limitations, but could be set up in a similar way.

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Actually a bank of LDR's as a straight up controller is a fantastic idea. Especially for simultaneous control of multiple params, as you say. I have a novation keyboard with a touchpad like a notebook PC. You can assign 2 CC parameters per axis (they crossfade in opposite directions, but also respond to multiple touches, a bit like mutlitouch) for both X and Y directions. It works really,really well. Explore all sorts of modulations just by moving the finger in a 2D "map". An arrangement of LDRs has even less limitations, but could be set up in a similar way.

Well I am glad someone like my idea! I think I get what you're suggesting I can use it as a crossfader with an extra property for light intensity (adding a third mixing element), right?

Edited by Fietspomp

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I have been reading in to midibox a bit more, and a question popped up, would I need a 32bit module or will 8bit do? I'm leaning towards 8-bit as I think my midicontroller is simple enough not to warrant 32bit, however how do I attach both usb and midi ports to this bare looking module?

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I think I get what you're suggesting I can use it as a crossfader with an extra property for light intensity (adding a third mixing element), right?

Well no, but that could be good too!

It could be something simple like a square array of 4 LDR's (say 5cm apart) each mapped to a different CC, so that different kinds of hand movement simultaneously control the 4 CC in relation to each other. This was how I interpreted your concept.

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I have been reading in to midibox a bit more, and a question popped up, would I need a 32bit module or will 8bit do? I'm leaning towards 8-bit as I think my midicontroller is simple enough not to warrant 32bit, however how do I attach both usb and midi ports to this bare looking module?

The very small extra cost of the STM32 core is very worth while to say the least.

There are many, many advantages of this as a platform especially, if you're developing and adapting application code for yourself, etc.

It may seem like overkill right now, but this turns into flexibility, and room-to-grow, not to mention amazing real time performance.

It has built in USB and many peripheral interfaces and options. (Forgive me for the going on about this, but the choice is clear, I reckon!)

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It could be something simple like a square array of 4 LDR's (say 5cm apart) each mapped to a different CC, so that different kinds of hand movement simultaneously control the 4 CC in relation to each other. This was how I interpreted your concept.

So that hand angle/shape dictates different relations between each parameter, right? That was indeed one of my thoughts, but since I'm using my own software anyway so I can explore many possibilities : ). Can't wait to get building.

Thanks for the tip on the STM32, I guess I'll buy that than. After this project I might build a bigger version anyway and the extra spec might come to good use.

Edited by Fietspomp

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