Arduino Lego EV3 Motor Controller SAVE $45

Introduction: Arduino Lego EV3 Motor Controller SAVE $45

By making a diy lego ev3 motor controller

Step 1: Intro

So i have a kit called the lego mindstorms EV3 it is an amazing $349 robotics kit which really is simple to build like lego but has really awesome features the kit features step by step instruction to make 12 robots including a humanoid which is super cool BUT THE SENSORS ARE SUPER EXPENSIVE it is highly fancy looking and everything is PRE-WIRED AND PRE-PROGRAMMED but expensive (eg: 20 ldr will cost you a buck while a light sensor of lego will cost you 20 bucks)

So being an arduino owner and fan i decided to fuse the 2 forming an awesome arduino controlled lego bot with mindstorms INSTEAD OF BUYING THE $45 SHEILD

this time i will be controlling motorS

Step 2: The Motors

There are 2 different servo motors for lego one is large servo and another is medium servo

The EV3 Large Servo Motor is a powerful motor that uses tacho feedback for precise control to within one degree of accuracy. By using the built-in rotation sensor, the intelligent motor can be made to align with other motors on the robot so that it can drive in a straight line at the same speed. It can also be used to give an accurate reading for experiments.Tacho feedback to one degree of accuracy160-170 RPMRunning torque of 20 (approximately 30 torque of 40 (approximately 60


The EV3 Medium Servo Motor is great for lower-load, higher speed applications and when faster response times and a smaller profile are needed in the robot’s design. The motor uses tacho feedback for precise control within one degree of accuracy and has a built-in rotation sensor.Tacho feedback to one degree of accuracy240-250 RPMRunning torque of 8 (approximately 11 torque of 12 (approximately 17

Step 3: Lets Get Started

You will need

1. Arduino (I used UNO)

2.Lego ev3 Connecter Cable

3.Lego ev3 motor

4.L9110S motor driver (or any but change the wiring also it shoul handle atleast 600ma mine can handle 800ma)

5.10K and 1K ohm resistor

Step 4:

Step 5:

Do the wiring as per the schematic



Step 6: Code

I dont think there is a need for code but here is a sketch of the motor running forwards and backwards

int motorPin = 9;
void setup(){

pinMode(motorPin, OUTPUT);


void loop() {

digitalWrite(motorPin, HIGH);


digitalWrite(motorPin, LOW);


digitalWrite(motorPin, LOW);
delay(1000); digitalWrite(motorPin, HIGH); delay(1000);


Step 7: TroubleShooting

Check that the resistors don't touch each other

No lose contact any where

Check the code

Plz comment if any more problems suggestions or question

Thank you for reading till here

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    1 year ago

    This has been posted for over 5 years. You should either finish the Instructable or remove it.


    Question 1 year ago on Step 4

    how do you connect it to arduino


    4 years ago

    Am I missing something? The wiring picture is too general. Can you show me how to connect the ev3 motor to the motor driver and the motor driver to arduino? I only see 1 picture wiring ev3 motor to some strange power function servo motor. and what is that? Thanks