Exchange Makeblock Orion Board with Arduino

In a MAKEBLOCK XY Plotter I want to exchange the Orion Board with an Arduino-Board ( so I can change the Pin-Allocation and add a SD-Card-Module for example).

To easily switch between the two microcontrollers and so I am not modyfiying the Makeblock-Hardware, I want to connect the Arduino-Pins to a RJ25-socket jack. Then I can simply switch the RJ25 cables from the Orion to the Arduino sockets.*

The motors are connected via the following driver: Motor Stepper Driver

Looking at the picture of the Driver-RJ25-Jack I therefore connected Pins 8 and 2 to DIR and STP , GND to GND, and VIN to V-M.

The Arduino is powered through the power jack (12 V power supply)

However as soon as I’ve connected the motor and the power supply, I can’t use the Serial communication anymore (no answer) and the big chip on the Arduino Board gets very warm, even hot when I try connect more than just the motor.

Is there an obvious mistake in this that I’m missing?

Sadly I am very new to anything hardware related. How could I go about finding the issue here?

Am I missing information you need to give me advice?

Orion Board: Orion Board (Schematic)

Power supply: Power Supply 12V 12.5A

“Schematic”: see attached picture; Leftside= Arduino Pins, Rightside = RJ25-socket Pins, RJ25 cable is connected to the driver

*I did see the explanation of how to connect the Driver to an Arduino Board, but I would really like to use the RJ25 –cable solution, so I don’t have to solder anything to the MAKEBLOCK-Driver

Sounds like you are overloading the Arduino's linear regulator. Your Orion board may contain a switching regulator/DC-DC Converter/"Buck" Converter. This will be better able to deal with the current demand and the 12V power supply. For most types of Arduino, using a 12V supply means very little current can be supplied before its linear regulator overheats and shuts down. It certainly can't supply enough to drive a motor.

To get suggestions about how to make this work, you must post a schematic showing how you have connected everything (hand drawn is OK) and proper clickable links to the specifications of all components used including power supplies.

For my understanding: where is the linear regulator situated? The point where it gets the hottest is on the long chip, a bit below the VIN-Pin .

Is there any way to explain, why Serial Communication with the computer isn't possible in that situation anymore, but for example a LED keeps blinking as it should?

The location of the regulator depends on the type of the Arduino, and that's one of several important pieces of information you haven't given us. Please re-read my previous post, and the forum guide in the "please read" sticky post.