NodeMCU ESP8266 + A4988 + Nema17 really weak

Projects General Guidance
1

Hi,

I have a project trying to motorize my roller blinds (they are pretty heavy), I have a nodeMCU ESP8266 powered by the USB port, connected to a A4988 driver, with a XL6009 voltage converter (5V input from the NodeMCU, 12V output for the motor) with a 100uf capacitor on the output, and a Nema17 motor.. I thought it would be strong enough for the blinds.. but I'm thinking I'm doing something wrong...

This is the schema of the project

The data for the Nema17 motor:
FOR NEMA 17 bipolar 1.65 inch x 1.65 inch x 0.79 inch 4 wire
This is Short Height FOR Bipolar Nema 17 stepper motor with 1.8 degree. Step angle (200 steps / revolution).
Each phase draws current 1A, giving a holding torque of 13Ncm (18.4oz.in).
Manufacturer Part Number: 17HS08-1004S
Motor Type: Bipolar Stepper
Step Angle: 1.8 degrees.
Nominal Current / phase: 1.0A
Phase Resistance: 3.5 ohm
Inductance: 4.5mH +/- 20% (1 KHz)

Vref for the A4988 driver is set to 0.67v

When the motor on the table, it turns nicely, but once I'm putting the beaded chain through the pulley - it's just trying to move, but cannot pull the chain..

Would appreciate ideas about what to check or how to fix.

Thank you.

2

Have you adjusted the coil current limit on the A4988? There are instructions on how to do so on the Pololu page for the A4988.

3

Hi,

Yes I adjusted it per to the video in the link - afterwards Vref is 0.67v

4

Uploaded a video of the motor working
Motor video

5

Do you have a DMM (Digital MultiMeter)? Does the motor power maintain 12V?

Are you using multi stepping? How much?

What speed are you running the stepper? Have you tried different speeds?

6

What is the source of the 5V?

7

with a XL6009 voltage converter (5V input from the NodeMCU, 12V output for the motor)

The Node MCU is powered from usb, and the 5v out pin can not supply the current required.

Power the XL6009 from a separate source.

8

Hi,

I just rewired the project as this - but still the same..

Now the NodeMCU is being power from a MB102 breadboard power supply (being connect to the computer via an Anker USB cable, the A4988 is connected the same way
The Nema17 motor is connected stright to a 12V charger I had laying around, with a 100uF capacitor across

Ideas what should I check next?
I replaced the NodeMCU to another one I had, replaced the A4988 to another one.. unfortunately I don't have another motor to test, but it seems that he's working

Could it be the software?

I'm running the Nema17 at full step, Vref take as 70% of Imax in calculations

Thanks

9

groundFungus:
Do you have a DMM (Digital MultiMeter)? Does the motor power maintain 12V?

Are you using multi stepping? How much?

What speed are you running the stepper? Have you tried different speeds?

Thank you for the comment,
I'm running at full step, not sure how to check at what speed i'm running the motor... could you explain how can I check/change that?

I have a DMM, tried to check the voltage of the motor over 1 coil, but it was changing too frequently (am I checking it wrong?)

10

I'm running at full step, not sure how to check at what speed i'm running the motor... could you explain how can I check/change that?

Post your code.

11

cattledog:
Post your code.

The code itself is a fork from this repo

with some changes in the constants

int MOTOR_STEPS = 200;
int MOTOR_MICROSTEPS = 1;
int MOTOR_RPM = 20;
int MOTOR_ACCEL = 20000;
int MOTOR_DECEL = 20000;
long int STEPPER_MAX_STEPS = 600;
long int STEPPER_POSITION = 0;
long int STEPPER_TARGET = 0;
bool STEPPER_REVERSE = false;
bool PERCENT_REVERSE = true;
int STEPPER_STATE = 0;
unsigned long STEPPER_TIMER = 0;
unsigned long STEPPER_TIMER_LAST = 0;
int SEND_WHILE_WORKING = 0;
int SEND_STATUS_INTERVAL = 10;
static long int step = 0;

A4988 stepper(MOTOR_STEPS, PIN_DIR, PIN_STEP); //full step

I could post all the code, but it's across several pages and quite long
If you know of a better sketch I should use (with MQTT support) I would appreciate it

Thank you

12

I am unclear about the popov code, but you might try to change MOTOR_RPM =20 to
MOTOR_RPM = 1 to see if slower speeds help.

However, In my opinion you should be working with simple test code for the motor before trying to integrate it into the popov blinds sketch.

See Robin2's

Simple Stepper Program

Stepper Motor Basics

Start with very slow speeds.