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Controlling stepper motor with a Ramps 1.4 shield

#1

Hi,

we want to build a driving robot, which is powerd by 4 stepper motors (one for each wheel). Therefor we bought a kit which included an Arduino Mega 2560 replica, a Ramps 1.4 shield and 5 A4988 stepper driver (https://eckstein-shop.de/3D-Drucker-Set-Kit-fuer-RAMPS-14-RepRap-Mega-2560-5x-DRV8825-12864-LCD-Arduino). The motors are 4 Nema14 stepper motors (https://www.omc-stepperonline.com/de/nema-14-bipolar-1-8deg-40ncm-1-5a-4-2v-35x35x52mm-4-drahte.html). The power supply comes from a 3D-printer and delivers 12V 20A.
Now we have three questions:

1.: Which of the two contacts for the power supply on the shield do we use, the 11A+ or the 5A? We found on another website, that 5A is a minimum and not a maximum when using 12V, correct?

2.: How do we communivate with the motors in or sketch? We found a picture of the circuit and decided to use pins A0 and A1 because they are connected to X-Step and X-Dir. To controll the movement of the motors we installed the AccelStepper library and wrote a first test sketch:

#include <AccelStepper.h>

AccelStepper Motor(1, A0, A1);

void setup() {
Motor.setMaxSpeed(2000);
Motor.setSpeed(500);
pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
Motor.runSpeed();
digitalWrite(LED_BUILTIN, HIGH);
delay(1000);
digitalWrite(LED_BUILTIN, LOW);
delay(1000);
}

To be able to see wheter our code is running or not we included the LED switches on and off. But the motor is’t moving at all and we can’t mesure any voltage between any of the 4 pins for the motor.
Is something wrong with our sketch, or might our shield be damaged?

3.: We are sure that we put the stepper drivers on facing the right way, the jumpers underneath were already on the shield. In theory we know, that you can controll the number of steps per turn with these. But how do you know, if a jumper is set as “yes” or “no”?

Thank you for your help! Since this is our first project with an arduino etc. we are a bit stuck.

Benedikt, Fabian, Christian

#2

Hello,

None of those products are Pololu brand, so you should probably check with the manufacturer about their connections and setup. I am not very familiar with the AccelStepper library, but you should probably start at a lower speed and concentrate on getting each motor moving individually with your hardware before putting the whole robot together. You might post on the Arduino forum to see if someone there is familiar with that library.

-Derrill