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Stepper Motors How to wire them up

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(@greendragon)
Member
Joined: 1 year ago
Posts: 27
Topic starter  

Hello:

This is my first post so cut me a little slack ok?

My robot set up =

Square box with Four Nema 17 motors one in each corner attached to a wheel.

Question =

Should I wire all four motors separately, or wire two together and then connect to a driver controller?

Thanks Bill


   
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Ron
 Ron
(@zander)
Father of a miniature Wookie
Joined: 3 years ago
Posts: 6865
 

Trying to keep both motors on 1 side in synch will be tricky. The side to side is similar but expected to be out of synch, that is where steering comes in to deal with that. Do some checking and see if most vehicles are 2 or 4 motors.

First computer 1959. Retired from my own computer company 2004.
Hardware - Expert in 1401, and 360, fairly knowledge in PC plus numerous MPU's and MCU's
Major Languages - Machine language, 360 Macro Assembler, Intel Assembler, PL/I and PL1, Pascal, Basic, C plus numerous job control and scripting languages.
Sure you can learn to be a programmer, it will take the same amount of time for me to learn to be a Doctor.


   
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Inq
 Inq
(@inq)
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Joined: 2 years ago
Posts: 1900
 

Posted by: @greendragon

Hello:

This is my first post so cut me a little slack ok?

My robot set up =

Square box with Four Nema 17 motors one in each corner attached to a wheel.

Question =

Should I wire all four motors separately, or wire two together and then connect to a driver controller?

Thanks Bill

Welcome to the forum.

That would depend on your steppers and stepper drivers and your goals of performance.  Most Nema-17 motors can handle nearly 2 amps (give or take).  If you're using drivers like A4988, they're only good up to supplying about 1 amp (give or take).  DRV8825 are good over 2 amps.  IOW none of these drivers can even fully drive 1 motor.  Two would be really likely burn them out. 

I would also think driving two motors off one driver would be bad since even the cheapest A4988 do sense how much current a motor is using.  That's its purpose for setting its maximum current settings.  How would it know the distribution of current being used by two motors?  It couldn't one motor might be drawing 90% of the amps and the other at 10%.  

Going with a driver on each motor... depending on your MPU of choice you should be able to set direction and step logic pins of two steppers off the same MPU pin... assuming you want both motors on a side to move in the same direction at the same speed.  

Good luck with your project.

VBR,

Inq

 

3 lines of code = InqPortal = Complete IoT, App, Web Server w/ GUI Admin Client, WiFi Manager, Drag & Drop File Manager, OTA, Performance Metrics, Web Socket Comms, Easy App API, All running on ESP8266...
Even usable on ESP-01S - Quickest Start Guide


   
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(@greendragon)
Member
Joined: 1 year ago
Posts: 27
Topic starter  

@inq 

Thanks that's what I was originally thinking - run them all separate.

Whats your opinion on using a TB6612 I2C Stepper Motor PCA9685 Servo Driver Shield V2 for Arduino?

Thanks - Bill

 


   
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Inq
 Inq
(@inq)
Member
Joined: 2 years ago
Posts: 1900
 

Posted by: @greendragon

@inq 

Thanks that's what I was originally thinking - run them all separate.

Whats your opinion on using a TB6612 I2C Stepper Motor PCA9685 Servo Driver Shield V2 for Arduino?

Thanks - Bill 

Again, it depends...  😆

I'd say if you're just getting started with any electronic/software projects the Arduino boards are forgiving and by being stackable, its hard to make pin mistakes or screw up solder joints.  Controlling them with I2C (I've never seen that before on stepper drivers) would free up the MPU's limited processing power as well as your software development skills.  Between an Arduino UNO and a couple of these Shields you're looking at $50 without batteries, stepper motors or any other electronics or hardware.

...on the flip side (you said to cut you some slack since it's your first post, but you didn't say what your MPU, electronics and/or software skillsets are) if you can use a breadboard and can do even decent soldering, then you can get by with a lot cheaper and more powerful solutions.

In example, I prefer using the ESP8266 and I'm starting to migrate to the ESP32.  Both of these are far better processors.  ESP8266 32bit/80Mhz or an ESP32 32bit dual-core, 240MHz than a UNO at 8 bits/16MHz.  Besides, they both include WiFi and the ESP32 includes Bluetooth so you can set up an RC control for your bot as your skills improve.  For drivers, I'd suggest of the DRV8825.  It'll supply 2.1 amps per phase.  That'll drive the largest Nema-17 (the honk'n 84 oz-in jobs) at their full ratings.  This solution will take some soldering and a little more work on the software side.  

References - Here's my current InqEgg project using the suggested (14 page thread) will bore you to tears.  I started a larger, faster bot... in the Inqster project should reach near 20 mph if it's stays stable enough at speed.  Both of these are going to be long-term projects as I learn AI.

Which-ever way you choose, it should be fun.  Good luck... if you go with the I2C units, please let us know how they go for you.  We haven't seen those here on the forum.  Sounds interesting!  

VBR,

Inq

 

 

3 lines of code = InqPortal = Complete IoT, App, Web Server w/ GUI Admin Client, WiFi Manager, Drag & Drop File Manager, OTA, Performance Metrics, Web Socket Comms, Easy App API, All running on ESP8266...
Even usable on ESP-01S - Quickest Start Guide


   
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