VC-mini building desciption

Started by sixeight, October 26, 2019, 07:46:01 AM

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sixeight

Here is how you can build a VC-mini:



Find the building guide here:
https://github.com/sixeight7/VController_v3/blob/master/VC-mini%20hardware/VC-mini%20MINI%20building%20guide%20-%20production%20model.pdf

For more information on the VC-mini check out the following links:
https://github.com/sixeight7/VController_v3

You can find the Teensy loader here:
https://www.pjrc.com/teensy/loader.html

And here is how you can get the components:

mooncaine

Thanks very much for that! It's encouraging to see it done and hear your explanation. Makes me think it might be possible, after all, for a doofus like me to assemble one.

sixeight

#2
This is interesting. Buydisplay finally sells RGB backlight displays.

EDIT: tried them, but the display uses transistors for switching the backlight and does not work with the WS2811 chip!!!!

https://www.buydisplay.com/default/rgb-backlight-positive-lcd-16x2-character-display-module



https://www.buydisplay.com/default/rgb-backlight-negative-16x2-lcd-character-display-module


wespac

#3



VC Mini installed in a Hammond 1455N1202 case...because it's what I had laying around. The board fits perfectly in the case, connectors fit flush on the sides.

sixeight

Quote from: wespac on November 20, 2019, 09:27:43 AM



VC Mini installed in a Hammond 1455N1202 case...because it's what I had laying around. The board fits perfectly in the case, connectors fit flush on the sides.

Wes, that looks awesome! I love it.

sixeight

#5
Have uploaded a new version of the STL's for the enclosure of the VC-mini to the github repository.

In this version of the enclosure the following issues have been solved:
* The hole for the middle switch was a little bit smaller than the other two - FIXED
* The enclosure would have a small gap at the front when it was closed - FIXED
* There was a small bit sticking out of the top part of the enclosure, that did not print well, because the filament did not have sufficient time to cool. FIXED




sixeight

#6
Received the RGB displays from BuyDisplay today, but unfortunately they are common anode, so they do not work with the WS2811 chip. So they cannot be used on the VC-mini, which needs a display with a common kathode backlight.

EDIT: VC-mini does use common anode backlight display, but the Buydisplay RGB displays have switching transistors on them, therefore they do not work with the WS2811 chip.

sixeight

Quote from: sixeight on January 08, 2020, 10:07:36 AM
Received the RGB displays from BuyDisplay today, but unfortunately they are common anode, so they do not work with the WS2811 chip. So they cannot be used on the VC-mini, which needs a display with a common kathode backlight.

Actually the displays are common cathode, even though the datasheet says they are common anode. Yet they need a high level to work:


This is how I understand it:


So am I correct saying there is an error in the datasheet?

sixeight

#8
Quote from: sixeight on January 09, 2020, 03:41:01 AM
Actually the displays are common cathode, even though the datasheet says they are common anode. Yet they need a high level to work:


Turns out the datasheet is correct. There are transistors on the PCB of the display that control the backlight. So they are common anode and share the ground pin with control side of the display board.

So it still does not work with WS2811 chip. Probably could pull off the transistors and connect them directly to get it to work, but it does not make life easy.

Elantric

Quote from: sixeight on January 09, 2020, 09:00:04 AM
Turns out the datasheet is correct. There are transistors on the PCB that control the backlight. So they are common anode and share the ground pin with control side of the display board.

So it still does not work with WS2811 chip. Probably could pull off the transistors and connect them directly to get it to work...

Some ideas
https://www.google.com/search?q=use+common+cathode+display+with+common+anode+design?&source=lmns&bih=510&biw=809&rlz=1C1GCEU_enUS868US869&hl=en&ved=2ahUKEwjnw5SVgffmAhUNmp4KHZLEAOsQ_AUoAHoECAEQAA

sixeight

Just to keep things clear for those that want to build a VC-MINI: the Adafruit RGB displays work fine. But they are more expensive than the Buydisplay RGB displays. I had hoped to find a cheaper in place alternative, but so far it does not work.

I will try to modify the Buydisplay PCB board to get it to work with the VC-mini. It looks like I can pull off some smd resistors and make some modifications to connect the led backlight directly to the pins of the display. That way the WS2811 chip on the VC-mini can control the backlight.


sixeight

#11
Quote from:  philjynx on January 09, 2020, 10:05:34 AM
Is that one chip to 'colour' all the displays the same, or one chip per display?

I dismantled a 1602 LCD a couple of days ago (the smoke had leaked out of the backlight diode - seems it didn't have a taste for 12 accidental volts). You could consider replacing the backlight diodes with the addressable type - bit of a chore but looks doable if you get small enough ones.

I paid under £2 each for IIC 1602s for my controller (monochrome).

The VC-mini only has one display. The full VController has 12 RGB displays and 12 WS2811 chips.  Each display can have its own colour.


billbax

Jaw dropping v-guitar/v-synth patch control, and impressive 'follow through' work sixeight!  8)

sixeight

#13
The Buydisplay RGB displays can be modified to work with the VC-mini. I have removed three smd resistors and added three wire bridges and now it works!


mooncaine

Isn't one lead supposed to be longer than the other?

sixeight

Quote from:  philjynx on January 11, 2020, 02:10:56 PM
I've always had difficulty remembering which end of a diode is which, till I read this "the symbol for a diode resembles a capital K" so this equates to the Kathode being where the K starts. I doubt I'll forget now. Perhaps that's why the backlight pads for a 1602 are marked A & K, Anode & Kathode.

Haha, yes I  know this stuff. Just wasn't thinking straight. Because the backlight didn't come on I concluded too quickly the LEDs had to be the wrong way around. It was later after I had posted that I realized I  was using a common anode RGB backlight in the VC-mini and then I found the switching diodes.

sixeight

Quote from: mooncaine on January 11, 2020, 08:14:25 PM
Isn't one lead supposed to be longer than the other?

On a new RGB led that is often the case. But on the display the LED is already assembled and all pins are cut to the same length.

sixeight

Did a comparison of both the positive and the neagative RGB backlight display from BuyDisplay. The negative one is almost unreadable when viewed from an angle. I will not use it on any VC-mini's I will sell. The Adafruit one is OK though.


sixeight

#18
A lot of people have been ordering PCB boards lately. Seems a lot of you guys are looking for some new challenges. Do post some pictures of your progress to keep us all motivated to finish our projects.

Still plenty of boards available if you want to take up the challenge!

https://www.dropbox.com/s/cx63t8tut3muiyj/VC-mini%20pricing%20and%20availability.pdf?dl=0

fantasiasoul

During the first UK lockdown, I decided to build a VC-Mini for my Katana 50. I had already built a 4 switch controller housed in a Hammond enclosure and liked the look and sturdiness of that. I, therefore, embarked to do use a metal Hammond enclosure for the VC-Mini.
I considered redoing the PCB but instead opted to do some wiring to reach the enclosure edges. I decided to only keep the connectors relevant to the Katana (so no midi sockets). Also, I wanted to position the power and USB sockets very close to each other and at a right angle. Very close to each other because both 9v power and USB are coming from the Katana amp (spanning from another project which added wireless capabilities to my Katana 50); I ended up wrapping both power and USB cable in the same sheath. Sockets had to be at a right angle to each other so that however you pull on the wrapped double cable you couldn't unplug either.
I used a 1590DD enclosure and led light diffusers. I also bottom-mounted the pcb so that no screws showed on the top of the pedal. I used a 6.35mm jack for the expression pedal socket. I positioned one encoder on each side on the screen so that they are more out of the way (of the feet). I spaced the footswitches further part so that you cannot dual click by mistake - I chose a similar spacing as the Helix Stomp (70mm apart). Some light insulation around the display to have no light bleed in the dark and a hammer paint job.
I have enjoyed using and plying with it immensely!! Thank you to sixeight for the immense work to create the vc-mini in the first place and all the help over email when I needed it.

sixeight

#20
Global chip shortage is making it very hard to get Teensy 3.6's. So there is a modification now to build the VC-mini based on a Teensy 4.1, as those are still readily available. If you are interested in doing a build, I can send you the details on the modification.



If chip shortage persists, I may have to do another version of the PCB, but I am hesitant to do that as the modification only requires four wires and I still have quite a few boards.

sixeight

#21
I have developed boards for the VC-mini based on the Teensy 4.1, as the Teensy 3.6 has been unavailable for the past 6 month due to chip shortage.



You can get these through my webstore: https://sixeightsoundcontrol.onlineweb.shop/