scratchcontroller
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scratchcontroller [2010/04/14 10:48] nils |
scratchcontroller [2016/07/04 01:44] psykhaze [Assembly] |
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| - | Hi. I'm making a MIDI scratch controller. | + | ======MB-Scratch Controller====== |
| - | ====== The problem ====== | + | |
| + | //By Rasteri// | ||
| + | |||
| + | {{ ::neonking:scratchcontroller.jpg?direct&600 |}} | ||
| + | ===== Introduction : DJ Controllers Issue ===== | ||
| MIDI DJ controllers generally come with "JOG" wheels, designed to allow the user to move through the track in a similar fashion to vinyl. These wheels are unfortunately nowhere near sensitive enough for scratching. In addition, the crossfaders included in such controllers are usually of low quality and/or too stiff to allow quick cutting. | MIDI DJ controllers generally come with "JOG" wheels, designed to allow the user to move through the track in a similar fashion to vinyl. These wheels are unfortunately nowhere near sensitive enough for scratching. In addition, the crossfaders included in such controllers are usually of low quality and/or too stiff to allow quick cutting. | ||
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| * A smooth, reliable, high quality crossfader with curve control. | * A smooth, reliable, high quality crossfader with curve control. | ||
| + | **[[http://midibox.org/forums/topic/10400-scratch-wheel/|Original Forum thread]]** | ||
| + | ===== Design ===== | ||
| - | ====== The solution ====== | + | ==== Crossfader ==== |
| - | ===== Crossfader ===== | + | The crossfader is the simplest part of the project. |
| - | The crossfader is the simplest part of the project. There are a number of faders on the market specifically designed for scratch DJs. For example : | + | For example : **[[http://www.innofader.com/whichinno.php|Audio Innovate Innofader]]** |
| - | * [[http://www.eclecticbreaks.com/proxfade/|Eclectic Breaks Pro-X-Fade]] | ||
| - | * [[http://www.infiniumtechnologies.com/|Infinium Technologies digital fader]] | ||
| - | * [[http://www.audioinnovate.com/|Audio Innovate Innofader]] | ||
| - | * [[http://www.vestax.com/|Vestax CF-CC]] or CF-PCV | ||
| - | The analogue ins of the PIC mean the fader can be used with no additional circuitry. Hooray! | + | ==== Jog Wheel ==== |
| - | + | ||
| - | + | ||
| - | ===== Jog Wheel ===== | + | |
| The jog wheel is slightly more complicated. After considering a number of options, I settled on an optical quadrature wheel design. This consists of two photodiodes spaced slightly apart, and a wheel with a pattern of slits round the circumference. By watching the slits go past the photodiodes, you can determine the speed and direction of the turning wheel. Wikipedia has a [[http://en.wikipedia.org/wiki/Rotary_encoder#Incremental_rotary_encoder|good page]] on this. | The jog wheel is slightly more complicated. After considering a number of options, I settled on an optical quadrature wheel design. This consists of two photodiodes spaced slightly apart, and a wheel with a pattern of slits round the circumference. By watching the slits go past the photodiodes, you can determine the speed and direction of the turning wheel. Wikipedia has a [[http://en.wikipedia.org/wiki/Rotary_encoder#Incremental_rotary_encoder|good page]] on this. | ||
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| I put the two photodiodes into two voltage dividers and wired them into pins 4 and 5 of the PIC. The comparators of a PIC18F4620 (or 4685) can be used to avoid extra circuitry. | I put the two photodiodes into two voltage dividers and wired them into pins 4 and 5 of the PIC. The comparators of a PIC18F4620 (or 4685) can be used to avoid extra circuitry. | ||
| - | ===== Software ===== | + | |
| + | |||
| + | ==== Software ==== | ||
| The MIOS code tracks the encoder wheel, and counts the number of forward and backward steps. Then every couple of milliseconds it sends the relative position as a CC event. The value of the CC is equal to 64 (0x40)plus/minus the number of steps, for example for 10 steps back the value would be 54 (0x36). | The MIOS code tracks the encoder wheel, and counts the number of forward and backward steps. Then every couple of milliseconds it sends the relative position as a CC event. The value of the CC is equal to 64 (0x40)plus/minus the number of steps, for example for 10 steps back the value would be 54 (0x36). | ||
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| - | ====== How To Build ====== | + | |
| + | |||
| + | ===== How To Build ===== | ||
| This is how to build the device the way *I* did it. It's not pretty (see photos) but works acceptably. It could be improved upon immensely if you have any actual construction skills, metalwork experience, access to a CNC mill, etc. | This is how to build the device the way *I* did it. It's not pretty (see photos) but works acceptably. It could be improved upon immensely if you have any actual construction skills, metalwork experience, access to a CNC mill, etc. | ||
| + | ==== Schematic ==== | ||
| + | |||
| + | {{ ::neonking:scratch-schem.png?direct&800 |}} | ||
| + | |||
| + | ==== Parts ==== | ||
| - | ===== Ingredients ===== | ||
| - | You will need : | ||
| === Electronics === | === Electronics === | ||
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| - | ===== Assembly ===== | + | ==== Assembly ==== |
| - | [[http://picasaweb.google.co.uk/rasteri/Scratchtroller/photo#5216080813603959586|Here is the assembly diagram]]. | + | {{ ::neonking:scratchtroller7.png?direct&600 |}} |
| - | Notes/Hints : | + | **Notes/Hints :** |
| * There should be washers between the nuts and the scratch wheel. | * There should be washers between the nuts and the scratch wheel. | ||
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| - | ====== Good Stuff ====== | ||
| - | |||
| - | ===== Code ===== | ||
| - | |||
| - | Code can be found in [[http://www.midibox.org/forum/index.php/topic,11167.msg94756.html#msg94756|this forum post]]. | ||
| - | ===== Schematics ===== | + | ===== Firmware ===== |
| - | [[http://picasaweb.google.co.uk/rasteri/Scratchtroller/photo#5216080810302030418|This schematic]] shows how to wire everything up to the PIC. Should be trivially adaptable to work with a "real" midibox core module. | + | Code can be found in <del>[[http://www.midibox.org/forum/index.php/topic,11167.msg94756.html#msg94756|this forum post]].</del><sup>dead link</sup> |
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| - | ===== Photos ===== | + | ===== Original Photos ===== |
| http://picasaweb.google.com/rasteri/Scratchtroller | http://picasaweb.google.com/rasteri/Scratchtroller | ||
scratchcontroller.txt · Last modified: 2016/07/04 01:46 by psykhaze
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