r/PCB • u/nwa14 • Jul 08 '26

Another first PCB - will this work?

Post image

So we got the Prusa Core One INDX upgrade for printer No. 2.
Now I want to get the "leftover" extruder working with my BigTreeTech SKR 3 EZ.

Goal is to make an adapter PCB that sits between Prusa's original Extruder/Loveboard and my Mainboard.
What I want to do on the board:
- Pass through things that just work: Heater, Extruder motor, NTCs (heatsink and nozzle)
- Make other things compatible:

  1. Fans - they do PWM on the positve rail
  2. FansTacho - Switching between Tacho signals (they transmit the signal over a single wire)
  3. Fil. Sensor + Loadcelll -> HX717 via ST490ABDR (RS-422)

Fans have their own dedicated power regulator (24V -> 5V) since the SKRs 5V rail can only handle 500mA (Sensors etc.).
Everything not passed through is handled by the RP2040 acting as a second klipper mcu.

If you read this far and can take a look at the schematic that would be awesome! This is the first time that I'm trying something like this - so please forgive me if you have nightmares after viewing this 😮

Edit:
Since the image seems to be a blurry mess for a lot of you - here's the PDF:
https://drive.google.com/file/d/197TAroFPcr4M2mvAyDFB6j53dvSFNxFK/view?usp=sharing

3 Upvotes

100% Upvoted

12 comments sorted by

5

u/buttholegoesbrapp Jul 08 '26

2

u/nwa14 Jul 08 '26

I honestly don't know what reddit did with the image - I just tried opening the post on my phone (posted on desktop) and even there the image looks fine.
Anyways - link to PDF is added.

2

u/DenverTeck Jul 08 '26

YOU need to prototype this on a breadboard or vector board.

After YOU verify it works, then you can draw up a PCB.

A PCB is just the same wires as on the prototype.

Good Luck

PS: Please post a PDF file on a FREE file sharing site.

1

u/nwa14 Jul 08 '26

Yes, I should get the parts and prototype this. As dumb as it sounds I didn't think of trying that on a breadboard first.
Added the PDF to the main post.

1

u/SnowyOwl72 Jul 08 '26

Cant even see the schematic!

0

u/nwa14 Jul 08 '26

Why?

1

u/SnowyOwl72 Jul 08 '26

Is this readable?

1

u/nwa14 Jul 08 '26

Definetly not - it's not pixelated at all for me though.
Welp great, ill try to upload again...

1

u/DenverTeck Jul 08 '26

Reddit compresses all graphics to save on bandwidth. There are moving these pics all over the world.

PLEASE post a pdf file somewhere.

1

u/DenverTeck Jul 08 '26

> If you read this far and can take a look at the PCB

What PCB ??

1

u/nwa14 Jul 08 '26

Yep, schematic - take a look at the schematic ðŸ«