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latigid on

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Posts posted by latigid on

  1. Open drain mode for STM32 gates

    in MIDIbox SEQ

    Posted

    Yes, this makes sense. Apologies, I did see this note but wanted to avoid the 74HC541 because I am already buffering the gates with my break out board:

     

     

    I wonder what is the best way to proceed while still using the board that I have. Do you think the buffers here would offer sufficient protection to simply use pull up resistors like I thought? Or would it be better to make use of a trimmer pot to have more control over the gain?

     

  8. Some questions about building a SeqV4

    in MIDIbox SEQ

    Posted

    Hello, and welcome to the forum.

     

    You have some good ideas for expansion of the SEQ concept but I am not sure exactly how you would go about implementing them.

     

    The parts kit for the Quad IIC is not as extensive for the SEQ, and there is no waiting list for this or the SEQ PCB as far as I know. LCDs can range from cheap and generic to quite expensive; you should check the backlight polarity and interface type (Hitachi HD44780) before ordering.

     

    It should be no trouble to build a simple control surface expansion on veroboard or even a custom PCB. There is a chain connection for additional shift registers on the main board which you can connect DIN and DOUT modules to in order to scan extra buttons or LEDs. Keep in mind that without (semi-complicated) matrix wiring the maximum number of inputs/outputs is 32 per module, you have 34 buttons in your design.

     

    The panel could be easily remodelled for the extra functions. The case is always more work than the panel, it is worth trying to locate this part first.

     

    The software side is where it gets tricky. I wouldn't expect anyone (TK) to program these changes for you as it is a single use-case feature set. It is also unlikely that everything can be run on the same core module due to memory considerations; additional routines may affect the timing performance. In my opinion, your best bet would be to use a keyboard program running on a separate core, even an 8-bit one. Then you can forward the MIDI into the SEQ for note editing.

     

    The SEQ does have a step-edit (303ish) mode, but I think what you are describing is a different application, and one which you would have to program yourself. The current interface is very powerful and there are many layers for accents and so on. Notes can be added with a standard MIDI keyboard.

     

    It is great that you are thinking about something different and applicable to you, but if you say that this is your first project I suggest that you start with a basic SEQ build and see how that goes first. It would be possible to build an expansion later if you found the current interface too limiting.

     

     

     

     

     

     

     

     

  17. PCB prototype service?

    in Parts Questions

    Posted

    There was a thread a few years back discussing PCB proto services, perhaps it is time to revisit.

     

    I would like to hear about any user experiences, including things like price, quality, turn-around time, shipping costs and so on. I have found a few so far:

     

     

     

    http://oshpark.com/

     

    * USD5 per square inch, for 3 copies. Flat mailer is USD8 worldwide, shipping from US. Directly parses EAGLE files and quality looks high (ENIG).

     

     

     

    http://www.elecrow.com/

     

    * 5cm * 5cm USD9.9 / 5cm * 10cm  USD23.9 / 10cm * 10cm USD23.9, 10 copies. ENIG more expensive, but you can choose a PCB colour for free.

     

     

     

    http://imall.iteadstudio.com/open-pcb/pcb-prototyping.html

     

    * Basically the same pricing structure as above, more for colours

     

     

     

    http://www.seeedstudio.com/depot/fusion-pcb-service-2-layers-p-835.html?cPath=185

     

    * Again, similar pricing structure (5*5 cm USD10, 10*10 cm USD25). Free shipping is available for orders over $50, you can combine with components or Arduino etc.

     

     

     

  18. MB6582 with Mean Well RPT-60B Switching PSU

    in MIDIbox SID

    Posted · Edited by latigid on

    You can buy triple output PSU modules from Mouser but then you will need to enclose them. I bought the MeanWell P25A14E for +5/+15/-15, I haven't hooked up the 15V rails yet but I hope to power the AOUT_NG inside my SEQ at some point. 

     

    Regulators have a certain voltage drop to contend with, which makes using a LM805 with a +5 V regulator edit: switching power supply impossible. Okay if your voltage is slightly higher.

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