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Wilba

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Posts posted by Wilba

  1. SPDT switch for velocity measurement

    in Parts Questions

    Posted

    I haven't found SPDT switches like you describe, and I've looked very hard.

    They must exist, because some controllers like the Axis-64 use them, I think.

    "Piano" type keyboards that have velocity sensitivity typically use two discrete switches... sometimes this is as simple as two rubber membrane switches that will close at different times of the keystroke, with different length actuators above it which are connected to the key.

    The Axis-49 uses an interesting method of a rubber membrane with two conductive rings at different heights:

    http://a2.vox.com/6a00cd972aa36b4cd5011015f5dc82860b-pi

    http://musicscienceguy.vox.com/library/post/the-axis-49-reveled.html

    I'm using a very time-consuming method to add extra contacts to Cherry MX keyswitches:

  5. MBBLM schematics and PCB discussions

    in MIDIbox BLM

    Posted

    That's the LED I was looking at. There is another one: http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=280516196821 but I don't know the brightness.

    BTW Don't forget to add the price of switch caps for the E-switch tactile switches, which are only available from Digikey AFAIK (part 401-1152-ND), another 48.12 USD for 289.

    This is why I stopped working on a design using E-switch, it's still a lot to pay for switches/caps and they wouldn't be illuminated. TK's DIY approach is better if you want to make it cheaply, and have illuminated buttons. The Livid pads aren't ideal, they're quite tall compared to the ones used on monome, making the overall height of the box at least 45mm, but the 0.8125" spacing keeps things smaller than the Sparkfun button pads, which means saving a bit on PCBs, panels, etc. It's still going to cost a lot just to make one set of prototype PCBs, but in a mini bulk order (20 orders) it should work out at under 100 USD for all the PCBs required, including driver boards... I'm guessing though... my mini bulk order of SEQ PCBs came to 32 AUD each, and this is over four times the board area.... but with a design using 3 pcs 16x4+4, 1 pcs 16x4+4+16, 5 pcs driver boards, that might bring the board cost down.

  6. MBBLM schematics and PCB discussions

    in MIDIbox BLM

    Posted

    I was already planning to use 3mm LEDs. It also would require some slight twisting of the leads so the lead spacing is smaller, 3mm bicolor LEDs typically have 0.1" spacing, meaning the outer leads are 0.2" apart, plus width of leads, this is too close to the inner edge of the conductive rubber ring. My current LED footprint has 0.0625" spacing, so outer leads are 0.125" apart. Pads are 36mil x 56mil round. No conflict with plated contacts on PCB which has inner diameter of 0.2" (same as conductive rubber ring on the button pad).

    While I haven't proved this yet, I think you would need some ultrabright waterclear bicolor 3mm LEDs, like found on eBay... and not the weak diffused kind like you find at Mouser (and what I used on my MB-SEQ). SMD LEDs might work but it's too hard to find them with good brightness and low cost, plus they might not illuminate the cap as well as a 3mm LED which is more in the middle of the hole. 3mm LEDs are cheap and available from many suppliers so that's good. It's bad enough to lock into one design/supplier of the rubber button pads.

    Even with 3mm LEDs, I still needed to do some tricks with the layout... like taking off the top layer pads, because 3mm bicolor LEDs are typically not soldered so close to the PCB, as the leads are so close together and have stupid right angle bends in them, the outer leads would touch a top layer pad around the middle lead. But when you think of the history of 3mm LEDs, they came from a time when single layer PCBs with wire jumpers everywhere were the norm... :wink:

  7. MB 6582 Power LED

    in MIDIbox SID

    Posted

    I didn't like any of the bezels and LED holders available at the time of designing the back panel, and I wanted the LED to look the same as the LEDs on the top panel, i.e. just poking through a hole in the panel. So I just made the hole 3mm diameter and glued the LED from the back using superglue. In case it's not obvious, header J2 (next to power switch) is where you connect the LED directly, resistor R81 does the current limiting.

  8. MBBLM schematics and PCB discussions

    in MIDIbox BLM

    Posted

    BTW don't get confused by the 0.813" spacing dimension in the 8x8 button layout: http://www.lividinstruments.com/media/64griddimensions.jpg

    Everywhere else in the Livid documentation, it's defined as 0.8125"

    I'm going to do a layout just for fun... matrix layouts are pretty easy and lots of copypasta anyway.

    Don't count on me to finish before anyone else or do bulk orders next week etc. :tongue:

    After layout of the button contact footprints, using a rough sketch of a circular contact, there seems to be enough room to route it all with two layers, it's a little bit easier since there's not so many through-hole pads getting in the way of the bottom layer tracks. The only thing I'm worried about now is whether the wider spacing of the bicolor LEDs would mean the outer pads might make contact with the conductive rubber of the button.

    e.g. look at this:

    BYOB64.jpg

    Does that dotted ring area around the LED represent the inner hole and the conductive rubber is outside that?

    If so, maybe even 5mm LEDs would fit in the hole.

    It looks like phunk used double the normal gap between button caps (0.250") so spacing between centers of the first row/column of buttons and centers of the extra left/bottom buttons is 0.8125" + 0.250" = 1.0625" I'll use that for now (unless phunk wants to correct me? :wink:)

  10. MBBLM schematics and PCB discussions

    in MIDIbox BLM

    Posted

    Looks like SMD LED will fit - here's a screenshot of a comparison between a few different layouts/button options on a 19mmx19mm spacing grid. The rectangle inside the Livid pad footprint on the left is the dimensions of an SMD LED.

    Wouldn't it be better if the pad contacts were circular like the SparkFun ones? Surely there would be enough room for a 3mm bicolor LED.

    The Livid ones are my current favourite.

    If I ever get time to build my own BLM16x16, I would probably do a sort of "modular" PCB using the Livid pads, 8x8 plus extra 8+8+1


    
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[/code]
    

    
then chop off the extra buttons on three of the boards, join together to extend it up to 16x16. Maybe each board has mounts along all four edges, so after chopping, you'd still have mount points for the top/right edges of the joined PCBs.
    

    
It might need a bit of extra wiring here and there to make it work, and something like the "stitching" method on my SEQ CS PCB proto.
    

    
[i][color=#FF0000]* Wilba scratches beard[/color][/i]
    

    
hmm....

  13. My sammichSID is complete and 100% working at first boot

    in MIDIbox SID

    Posted

    That happens to me too, with some LCD/PSU combinations. Unfortunately, sammichSID design is a compromise between overall size, heatsink size, overall current draw, LCD current draw (brightness), PSU voltage/max current, parts cost, etc. Powering the LCD from the (potentially) unregulated input voltage is a big hack, but it doesn't generate more heat out of the voltage regulators and heatsink.

    If SIDs didn't need dual voltage, it would be a lot simpler *sigh*

  16. mb-6582 firmware upload problem

    in MIDIbox SID

    Posted

    If you want to reproduce this same sound in a patch (after startup), this is what the patch is... converted from the registers being set:

    Volume set to 15

    Filters off.

    OSC 1 Pulse waveform, Attack 0, Decay 0, Sustain 8, Release 8, Pulse Width 800, everything else zero/off.

    OSC 2 and OSC 3 are off.

    This is almost identical to the init Lead patch... looks like only Sustain and Release are different.

    It would be interesting if you could reproduce the click in a patch, or not, and then know if it's a startup-only issue or your SIDs being clicky.

    So the 2x 6582A that came with the sammichSID don't make this clicky sound?

  19. My sammichSID is complete and 100% working at first boot

    in MIDIbox SID

    Posted

    MY LCD gets occasional flicker and dimming. It's slight, but noticeable. Is this normal or is there something I should start looking at as the cause?

    Flicker/dimming is not normal.

    It could be a bad solder joint in the backlight circuit.

    Check solder joints in that area. i.e. J16 pins 15,16 (or equivalent on LCD), T1, JR4, R4, P1, JBL.

    Maybe the P1 pot wiper is making poor contact. Try turning it a little. Also JR4's shunt might be making poor contact.

    It could also be a current supply issue, but I think you posted a link to a good PSU so it's probably not that. Check if it still happens when P1 set to 1/3rd brightness (instead of 1/2).... or if you remove the SIDs.... or if it happens when sammichSID isn't doing anything (i.e. take out the PIC).

  22. Sammich Issues

    in Testing/Troubleshooting

    Posted

    I think you may have multiple issues.

    You will need to sort out either the control surface issues, OR the SID issues. Both might be related to the same problem.

    I would probably say the SID issues are easier to resolve, because there's less things to check, only one PCB where there might be a problem.

    You can try the testtone app with the SIDs removed. This helps identify if there's a problem with the audio buffers (i.e. the noise comes from them). Take out the SIDs and put a 1K (or similar) resistor between socket pin #8 and #27. Make sure you connect it in the right pins! Pin #27 will NOT have 9V! Connecting 9V to pin #8 is BAD

    You should get 1kHz out of the audio outputs, this will probably be at max volume level too. If you don't, there's a break between pin #8 and the PIC, OR the audio buffer is the problem. You can narrow this down by connecting pin #8 from the left SID socket to pin #27 of the right SID socket (and vice versa).

    BTW are you sure your audio is working? You are using a stereo plug?

    The interconnection test is supposed to validate that the PIC->SID connections are correct, as well as connections to the two 74HC595 ICs below the SIDs. If you're not getting the right voltages when you send the Mod wheel message to change which pin is high (for the pins connected to the 74HC595), then there's some issue with the three serial data lines between the PIC and the 74HC595.

    Check for bad solder joints, shorts, breaks, etc. between the PIC and the SID sockets, 74HC595 sockets.

    AFAIK a high noise floor might result from either the audio input not being grounded (some issue with the audio input socket, or tracks between there and the SID pins)... OR if setting the volume registers in the SIDs isn't working, because the data lines aren't working. So until you get the interconnection test working properly, I would say not worry about high noise floor, that might be fixed by fixing the interconnections. Also, if you are still observing high noise floor when SIDs are removed, then it obviously has nothing to do with SIDs or the interconnections... some issue with voltages like the 9V supply, or ground, or the audio buffers. Try to identify if the noise is on one or both channels perhaps.

  23. Sammich Issues

    in Testing/Troubleshooting

    Posted

    Take off the control surface PCB. You say pressing buttons has some audible effect, this shouldn't happen.

    There are two test apps you can use.

    http://www.ucapps.de/mios/mbsid_interconnection_test_v2.zip

    Testprogram for the interconnections between Core and SID module of MIDIbox SID (read the README.txt file for the usage)

    http://www.ucapps.de/mios/mbsid_testtone_v3c.zip

    Just plays a 1kHz triangle wave on the SID - nice for testing the audio output without the need for a MIDI sequencer or keyboard. With the new v2 version, both MBHP_SID modules connected to a core are initialised.

    In addition, a 1kHz square wave will be generated on the CS pin (#8) - see xxx for additional informations.

  24. mb-6582 firmware upload problem

    in MIDIbox SID

    Posted

    You need to troubleshoot the MIDI.

    http://www.ucapps.de/howto_debug_midi.html

    You can't tell yet whether it's MIDI In or MIDI Out that is the problem.

    i.e. MIOS Studio sends SysEx and expects SysEx response. If MIDI In doesn't work, the PIC won't respond. If MIDI In works, but MIDI Out doesn't, the PIC responds but it's not received by MIOS Studio.

    Do the loopback tests etc. The how-to is for Core8 module, but you can use the MB-6582 base PCB diagram to match things. Don't forget that J11 controls which PIC Tx pin connects to the MIDI Out (via the 220 ohm res).

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