Minimum PCB Design for DevKitC

[marosell]

I plan to order this one, so if someone can review, I would much appreciate it. I will build and test once ordered. Minimum order is 3 boards; I'm happy to send a board to assist with development, just let me know where to send.

This is based on the ESP32-DevKitC-32U for a few reasons:

• Separates the screen from the board, allowing more placement options in an enclosure
• Provides antenna attachment, allowing for external antenna to be mounted to quality aluminum pedal enclosure

Link to board: [Redacted. V2 link below]

PedalinoMini DevKitC_pcb.pdf
PedalinoMini DevKitC_etch_silk_top.pdf
PedalinoMini DevKitC_etch_copper_top.pdf
PedalinoMini DevKitC_etch_copper_bottom.pdf

[marosell]

Last revision for today. Updates include:

• Power options along the bottom of the board, including 9V power, switch header, and 9V/5V conversion header. If user is planning on a DC power connector on a breakout board, simply bypass the switch with a jumper. I recommend installing a bridge rectifier (Diotec B40R or similar) on the power breakout if using a power connector.
• Power options for external midi module; 3.3V or 5v can be selected using a jumper.
• Unused pins from the board have pads for testing or future use.
• Grounded screw holes.
• General cleanup and simplification.

PedalinoMini DevKitC_pcb.pdf
PedalinoMini DevKitC_etch_silk_top.pdf
PedalinoMini DevKitC_etch_silk_bottom.pdf
PedalinoMini DevKitC_etch_copper_top.pdf
PedalinoMini DevKitC_etch_copper_bottom.pdf

[marosell]

Alright, we're at V. 1.0 on this board and it's ordered and off to production!

Final changes:

• Backtracked on grounded screw holes to avoid ground loops.
• Found room for the 9VDC bridge rectifier, so I added it. In lieu of the rectifier, 9V battery wires can be added to the +/- pins in this location.
• More cleanup.

PedalinoMini DevKitC B_pcb.pdf
PedalinoMini DevKitC B_etch_silk_top.pdf
PedalinoMini DevKitC B_etch_copper_top.pdf
PedalinoMini DevKitC B_etch_copper_bottom.pdf

[alf45tar]

Thanks Mike

[marosell]

I actually found an issue with one of the pins, so I had to reorder. I found that for not much more room on the board, I could add Midi Out using Pete's schematic. So here is V. 2.0:

PedalinoMini DevKitC C_pcb.pdf
PedalinoMini DevKitC C_etch_silk_top.pdf
PedalinoMini DevKitC C_etch_copper_top.pdf
PedalinoMini DevKitC C_etch_copper_bottom.pdf
PedalinoMini DevKitC C_etch_silk_bottom_mirror.pdf

[mknerr]

This is great! Can you link to the V2 board on aisler.net? Also, if you have a prefered source for the devkitC board would be appreciated. Thanks for your efforts!

[marosell]

This is great! Can you link to the V2 board on aisler.net? Also, if you have a prefered source for the devkitC board would be appreciated. Thanks for your efforts!

I can, but I was not impressed with the first order I did through them, so I ordered from someone else for V2. But I will upload it there anyways so you can see it: https://aisler.net/p/GCLIIISP

I have five V2 boards coming my way and I can send you one when they come in (for less money than you'll pay Aisler) but understand this is for testing/development purposes as this hasn't been tested. I have some other components I can include that the board calls for, too:

• Midi Logic Gate
• 1/4w 200 ohm resistors
• 1/4w 10k ohm resistors
• Bridge Rectifier - I wasn't happy with the availability/sources for the B40R so I ordered some 2W10 as a substitute. Not needed if you are planning to run off USB power. Make sure this is soldered correctly, there are +/- symbols on the board. If you intend to use this, double check the polarity of the power coming from the rectifier BEFORE it powers the rest of the board!
• Midi Connector
• Male header pins

I don't have extras of these, but you'd only need the following for non-USB power (in addition to the bridge rectifier above):

• 9vDC to 5vDC Converter - There is a spot on the bottom of the board for this and assumes female jumper pins will be soldered to the board and this plugs right in. If you intend to use this (and after you've double checked correct polarity from the rectifier above), double check that you have 5V leaving this sucker BEFORE it powers the rest of the board! If all of the above are OK, you will also need one of the following:
  -- DC Jack and either solder across the SPST drill holes or install male pins and connect with jumper (preferred method of bridging that connection), OR
  -- 9v Battery Lead with wires soldered to the +/- spots of the Bridge Rectifier location INSTEAD of the Bridge Rectifier, and a SPST switch of some kind to save the battery when not in use (I'm not planning on running on battery, so I didn't source). This is if you wanted to use a 9V battery, not if you wanted to use a 5V battery connected through the USB port. Instead of a switch, you could also just open your pedal and unplug the battery every time.

Authorized distributers for ESP32-DevKitC-32U:

• Mouser - ~400 in stock
• Digikey - 0 in stock

And don't forget your antenna:

• Antenna. I had an extra lying around from an old PCI wifi card I wasn't using.

[mknerr]

Thanks for the very thorough response! And yes, I'd be interested in getting a board and the parts you have available. I think I have the rest anyway. Let me know how you would like to proceed. I think I setup an email in my profile.

[marosell]

Thanks for the very thorough response! And yes, I'd be interested in getting a board and the parts you have available. I think I have the rest anyway. Let me know how you would like to proceed. I think I setup an email in my profile.

I checked your profile and couldn't find it. I have added my email to my profile. I think it will be two weeks before the boards come in.

[marosell]

Boards are in, I've built one and will be testing, and @mknerr will test one as well. Here are some pictures:

[alf45tar]

Very nice and good job.

[marosell]

Was able to do some testing today and made a few short videos:

• Testing MIDI-out: https://youtu.be/BEKNbTDvX7c
• Testing IP-MIDI: https://youtu.be/dNtW2n366bU

[athlonwai]

Hi Marosell,

What kind of buttons are you using in the video?

[marosell]

Hi Marosell,

What kind of buttons are you using in the video?

They were some cheap buttons that came with a breadboard kit. For an actual enclosure, I plan on using momentary foot switches from a pedal parts supplier.

[mknerr]

Well, I know it’s been awhile, but thought I would give an update on my build with this PCB. It’s still a work in progress, and kind of a proof of concept at this point. She doesn’t know what she wants to be when she grows up. Lol. Obviously I can’t use the MIDI DIN with this enclosure. Might change it out for a 3.5mm jack, or just “piggy-back” one on.
Right now, I just have the two jacks for switches, but will definitely expand it.
Big kudos, credit, and thanks go to @marosell for developing the PCB and, of course, to @alf45tar and other contributors for the software, making it possible for people with limited time and skills to make such a powerful controller.

[alf45tar]

Nice

[jisv48]

Thanks for the very thorough response! And yes, I'd be interested in getting a board and the parts you have available. I think I have the rest anyway. Let me know how you would like to proceed. I think I setup an email in my profile.

I checked your profile and couldn't find it. I have added my email to my profile. I think it will be two weeks before the boards come in.

Hello Marosell, can we order the boards thru you or thru Aisler.net as you mentioned above. Thanks in advance

[marosell]

Have at it!! https://aisler.net/p/GCLIIISP

I saw your PM and will respond. If anyone else wants a board, I can order a batch and send them out less than Aisler's min. order amount, but I think they have a good price on a pack of three, which will give you some to practice with.

[A7F]

@marosell sooo I am planning to build a pedalino pedalboard but I was wondering if it would be doable something similar to the midicommander in the sense that it has all the I/O in the back side: the two midi I/O ports, usb midi port and two expansion ports for expression pedals. How do you deal with powering the whole thing? If I understand correctly your PCB, it still needs two power sources in case you use USB midi which is not super comfortable... I mean, the best thing would be to add some rechargeable batteries, right?
Also the PCB doesn't seem to support addressable rgb strips?

[mknerr]

Apologies if I'm covering anything you already know. If you use USB MIDI, the micro will get power from the host. But, if you want to setup the pedalino as host, it would need power, I'd think you would still only need one supply.

The board is setup to allow for a higher voltage input, like 9-12V, but converts it down to 5V with a buck converter, then sends it to the ESP32 board. You could tap tap off of that if you need to. You can also just use a 5V supply, or even just power with the micro USB. Just depends what your needs are. The power input circuitry is mainly for convenience if you are using on a pedalboard rig which typically has 9V available already.

And yes, you could also use battery power.

RGB support was not in the code when this was designed, so no, it does not support that directly. But, he did, thoughtfully, include soldering pads for the unused pins which should make that possible.

[A7F]

Apologies if I'm covering anything you already know. If you use USB MIDI, the micro will get power from the host.

hey thanks for answering 😄
I'm sorry, I think I'm getting confused... what about the ESP32? By looking at the PCB you assume the current coming from the Pro Micro (200mA I suppose?) is enough to power the whole thing (ESP32 as well) but what if I add let's say 10x WS2812B leds? Only those 10 leds draw 500mA...

[davidin73]

Hi!!!! I'm (slowly😭) working on a @marosell' pcb (thanks Mike ,is a great pcb).
Here some enclosure' and a populated pcb' photos

[mknerr]

@A7F no sorry, the host would power the pro micro only; I just meant you wouldn't have to power it separately. I guess I'm a little confused on what you meant by needing two power sources.

But, regardless, one power supply, whether it's battery or mains, should do it, as long as it has the current you need for the number of LEDs you want to use.

[FabrizioGrasso0289]

i apologize for this obvious question to those who are savvy in this. Where does the arduino Nano/Micro goes in this board?

[basst22778]

@marosell i have problems finding the logic chip for midi out.
Do you think this chip from TI will match?

https://www.reichelt.de/single-bus-buffer-gate-mit-3-state-ausgaengen-sot-23-5-sn-74lvc1g125dbv-p219307.html

DATASHEET: https://www.ti.com/product/SN74LVC1G125-Q1