This is my attempt at a better 3D printer controller board. This is my first attempt at creating a fully realized product.

Specs:

3x 12-36V power inputs

3x Large (15A) MOSFETs, one for each power input

3x Small (7A) MOSFETs, one for each power input

4x Thermistor inputs connected to a 12-bit ADC

4-6x Stepper controllers supporting up to 3A steppers each

4-6x Endstop controlled by stepper controllers.

8x unused GPIO pins

1x SPI header/pins with dedicated CS (Raspberry Pi also supports using other GPIO pins as CS)

On board 3.3V and 5V regulators

USB Micro B - Male connector for providing power to the Raspberry Pi via the onboard 5V regulator

Supports Raspberry Pi 3 or Raspberry Pi Zero

Only 100m x 100mm

How its done:

Thermistors: I use a 12-bit ADC that communicates to the Raspberry pi via SPI

Stepper Controllers: The stepper controller I choose communicate with the Raspberry Pi via SPI and are chained together (using a single CS). Steppers are powered via the #1 power input.

Endstops: Each stepper controller supports a single switch which can be queried via SPI communications.

MOSFETs: I have added one large (15A with a XT30PW connector) and one small (7A) MOSFET to each power input (each input has a XT60PW connector) and created large copper filled zones to provide plenty of power to each.

GPIO: by using SPI to communicate with many of the components, there are still plenty GPIO pins left to do interesting things like controlling servos and whatnot.

What I need:

I really need someone with real electrical engineering expertise to review and correct/guide the design in the right direction. I am programmer and I am only self taught in electrical design. I *think* I have got it pretty close, but I want to get it solid (as is possible) before I build a prototype to start the software development on.

I plan on writing the software in Linux so it can run on one of the Raspberry Pi distros. I have also considered writing it in .Net as to leverage Windows 10 IoT, but I think that a Linux version would be more useful (at least to start with).

Anyone willing to help (either hardware or software) please private message me.