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rasteri

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Posts posted by rasteri

  4. Scratch wheel

    in MIDIbox User Projects

    Posted

    Sorry I haven't been around much, but I'm not really using midibox anymore. Just a quick update though, I figure ya'll might be interested.

    The standalone scratch code has been ported to the dsPIC, largely because I was attracted to its DSP instructions and builtin audio DAC. I'm now beginning to regret this decision, partly due to the proprietary toolchain, but mostly because none of the models with a DAC have USB support :/

    I guess I'm either gunna port the code to MIOS32, or move to another PIC (24f series perhaps?) and use an external DAC (the TI PCM1770 looks rather tasty, for example).

    Are presoldered STM32 boards available yet? I guess that might sway my decision...

  7. Scratch wheel

    in MIDIbox User Projects

    Posted

    I'm just drawing them in Inkscape. There are probably a million more elegant ways to make one, but the method I've been using is -

    1) Draw a line the diameter of your encoder wheel.

    2) SELECT ALL, then copy and paste in place.

    3) Rotate the copy 90 degrees (forming a cross).

    Repeat steps 2-3 over and over again, halving the rotation angle each time (so 45deg next, then 22.5, then 11.25, etc) until you have no space left between the lines to paste.

    Remember - it's a quadrature encoder, so each line actually adds 4 steps per revolution. If you have 360 lines, that's 1440 steps. I really wouldn't go any less than 1048 steps per revolution TBH - that's about the minimum I could get away with without it starting to feel weird.

    I really gotta start putting all this on a website somewhere.

  11. Scratch wheel

    in MIDIbox User Projects

    Posted

    I forgot to mention that the diagram is all drawn to scale with the containing box representing the inside dimensions of the flight case. Actually found a cheap enough flight case on ebay which is the one i am doing my measurements on. The cool thing about this case is that you can whip off the lid completely as its a guitar effects rig case. This means the lid won't get in the way when you are dj'in!

    Sweeeet.

    so if the cost of building the scratch wheel is less that say £25 in total (each) then i think this setup would be much cooler and better value than the numark total control priced at £155 (amazon.co.uk)

    Well the cost of each scratch wheel is probably a bit more like £50 by the time you add buttons and shit. But you can't scratch with the numark total control.

    p.s do you think the xsessions crossfader will be good enough for mixing?

    Yup. Faders don't need to be very good for mixing.

  12. Scratch wheel

    in MIDIbox User Projects

    Posted

    That's an unbelievably cool idea, I especially like the second picture. I was going to say that the x-session's crossfader sucks for scratching, but as long as you keep the crossfaders builtin to the scratch devices, that won't matter at all.

    I think I'll build myself one now :)

  13. Scratch wheel

    in MIDIbox User Projects

    Posted

    Do I need (sould I use) an external soundcard? The one on my laptop has four outs, but two are digital signal only.  Could I just buy a USB surround sound card and get Traktor to assign one deck to the front and the other deck to the rear outputs?

    You don't NEED an external soundcard - I use my laptop's internal soundcard all the time. Get hold of a program called ASIO4ALL, and set traktor to use it for output instead of directsound or whatever.

    External soundcards are a good idea in general though. I wouldn't get a surround card, they're mostly for home cinemas and stuff and might not come with ASIO drivers. I suggest you get one with four discreet outputs that you're sure will come with ASIO drivers. M-audio make some pretty good ones.

    Instead on gutting my Vestax PCV-275, I think I'll order 45mm Infinium fader.  I know the Rodec Scratchbox uses a beefed up version of the Infinium fader.  I think they'll work, they have analog outputs.

    The infinium looks like a GREAT option, I encourage you to try it out - I haven't had a chance yet. The only problem is it wants a 3.3v power supply, so you'll need to add a 3.3v regulator. Also the code will need to be modified slightly, but that's an easy job (I'll do it for you if you give me some ADC readings). In the long term I'll look at interfacing with the infinium's SPI port.

    Also infinium make a retrofit version of the product, which costs slightly more but should just drop straight in without a new regulator or code modification. http://www.infiniumtechnologies.com/downloads/20070330_3/download - maybe give that a go?

  15. Scratch wheel

    in MIDIbox User Projects

    Posted

    I have a laptop, hence, no MIDI card.  Do I need a USB to MIDI or Firewire to MIDI adapter if I want to connect this device to my PC?

    Yup. They're not too expensive, I got my USB->MIDI adapter on ebay for under £10.

    I have no background in programing (but I'm not a fool!).  How difficult would it be for me to get a device like this working

    You won't need to do any programming. All you need is a midibox core module kit (buy from smashtv, get one with a preprogrammed PIC18F4620) and a soldering iron.

    For rasteri: is this device connected to a more sophisticated piece of hardware, like FinalScratch or Native Instruments Traktor Scratch, or is it fully independent?

    It's connected to a PC running Traktor. I have built a prototype version that is completely standalone and is powered by batteries, but I'm in the middle of porting it to a dsPIC (for lower power consumption and cost) and that will take another month at least. Rest assured I will make details available (including source code) when I'm done.

  16. Scratch wheel

    in MIDIbox User Projects

    Posted

    Yeah I saw that story. There are a few problems involved in using an HDD motor for this project -

    1) They have a much lower resolution than we need - something like 400 steps per resolution, which isn't really enough IMHO.

    2) The signal they produce is different - it uses 3 lines instead of 2. Coding around this would be pretty easy, but *I'm* not going to do it because of reason 1. Feel free to have a go yourself.

    3) Related to point 2, the PIC only has 2 comparators. They can be multiplexed, or you could just use external comparators like that guy you linked to did.

    In all honestly, you're better off with an optical encoder. Those HD motors make great bearings though - you could attach an encoder wheel to it perhaps?

  18. dspics

    in Design Concepts

    Posted

    well I figured since it's only like £25 I didn't have much to lose. Except perhaps my soul to microchip (It feels really strange using the official PIC dev tools, I've only ever used homemade programmers for ~8 years)

    Microchip supply schematics for it, and people have designed PCBs so you can make your own pickit. I believe there is linux support for it, too. (but not for dsPICs...)

    And I'll be sure to post details of the project when it's semi-working.

  20. dspics

    in Design Concepts

    Posted

    I wanna experiment with the dspic33f series, but I can't find any good DIY programmer schematics (let alone software). Does anyone know about any I might have missed?

    I was thinking, since I'll be going with the official Microchip toolchain (C30) and MPLAB IDE, I might just get a PICKIT2. Does anyone have any experience with these programmers? They seem very handy, especially as I have no serial or parallel ports on my new comp...

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