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Topic: Trimpod with step motor A4988  (Read 5729 times) previous topic - next topic

allanhurst

Cheapo pots such as used on these shields will only handle a certain number of setting operations without failing.. a few hundred?

 don't overdo it

regards

Allan.

batata004

@ChrisTenone yeap, you were the only person who said a valid thing here. The screw was loose! It should not spin infinite times CW or CCW. I fixed it now it only spins once :)

I just need to know if CW or CCW is increasing/decreasing current, just that guys.

I am not stupid and I will not buy a multmeter only for this. Ok? Let's put this behind us and stop discussing this.

If you cant do anything without a multmeter you are not smart and you are not creative. I built and ENTIRE QUADCOPTER from scratch, ALL THE CODE, ALL THE CONNECTIONS I made by myself without a multmeter. Dont believe? Check this: https://www.youtube.com/watch?v=scug89PNQlg

I DONT NEED A MULTMETER, end of story. Some of you are not as creative or resourceful as I, so you surelly need a multmetter, you need to pay a course to learn arduino, to learn programming... I did all by myself, never had a programming course in my entire life, never had an arduino course in my life. I learned all from e-books and books - I know how to read, ok?

I also developed this really simple self balacing robot FROM SCRATCH -> https://www.youtube.com/watch?v=BjrJEmjz8go

 As I did with my quadcopter, I DIDNT USE ANY CODE FROM ANYONE. I created my entire code, ENTIRE CODE. Only used servo library and JEFF ROWBERG library and nothing else.

So please, stop saying I should quit this hobby cause you sound really stupid saying that.

rpt007

#17
Aug 31, 2016, 02:10 pm Last Edit: Aug 31, 2016, 02:12 pm by rpt007
Quote
I just need to know if CW or CCW is increasing/decreasing current, just that guys.
Nobody can answer this question as long as we don't know the make of your A4988.
There are the original ones made by Pololu and there are some cheaper Chinese clones.

The original ones from Pololu increase the current by turning the trimpot clockwise (CW).
Most clones increase the current counter clockwise (CCW) - but you never know what the design actually looks like and with clones you even can't trust their manuals - given that you got one.

Attention:
The trimpot range is about 270 degrees - a very small move can cause a high current jump, depending on your driving voltage.

Quote
I DONT NEED A MULTMETER, end of story. Some of you are not as creative or resourceful as I, so you surelly need a multmetter, you need to pay a course to learn arduino, to learn programming
As all previous people said, I only can repeat it: You NEED A MULTIMETER.
Believe it or not - you CAN FRY your stepper when you don't adjust the current to the max current of the motor.

And - this has nothing to do with how good you are at PROGRAMMING; here we are talking about basic electronics and as an engineer I only can say, measure, measure if you don't want to kill your devices and burn your money. But the final decision is up to you.

When you are driving in your car (supposing you are a driver) - do you FEEL the speed or do you look at your dashboard? The same applies here if you don't want to be caught by the fireman...

If you come to the conclusion it might be cheaper not to burn your steppers, then you can read some deeper information about how to set up a A4988 (or a DRV8825) and if the current setting happens CW or CCW etc.
You will find it here:
http://forum.arduino.cc/index.php?topic=415724.0
Before you ask:
Did you really read and understand How to use this forum ?
AND:
Do you have already some solution or is a part of the problem sitting in front of the screen?  :)

pwillard

Quote
I DONT NEED A MULTMETER, end of story. Some of you are not as creative or resourceful as I, so you surelly need a multmetter, you need to pay a course to learn arduino, to learn programming... I did all by myself, never had a programming course in my entire life, never had an arduino course in my life. I learned all from e-books and books - I know how to read, ok?
Simple Fact:   You are nowhere near as smart as you think you are and you are not smart enough to realise it.

Fact:   Turning the Stepper Driver board trim pot more than a full revolution will result in it ultimately breaking.  The component "wiper" is not designed to be turned even 1 full circle much less 100. It is most definitely not a multi-turn potentiometer.

Fact: Counterclockwise on that board = Less current  Clockwise = More current.  You clearly are not resourceful enough to find a datasheet on a relatively common stepper driver board or you could have found this answer yourself.

Recommendation:   Find a different hobby.  

raschemmel

Quote
Anyway, I would like if you could reply me if the trimpot accepts 100 spins of after a certain point it stops couting the spins.
More than likely it is either a single turn pot or a 10 turn pot but since you did not post a vendor link for the A4988 it is impossible for us to know.

rpt007

@pwillard:
Quote
Fact: Counterclockwise on that board = Less current  Clockwise = More current.
Only true for Pololu originals. Most clones are increasing CCW! See my reply #17.

I think, the OP has now enough information to think about and make up his mind.
It's not our money and time which he might be burning ...
Before you ask:
Did you really read and understand How to use this forum ?
AND:
Do you have already some solution or is a part of the problem sitting in front of the screen?  :)

rpt007

@raschemmel:
Quote
More than likely it is either a single turn pot or a 10 turn pot but since you did not post a vendor link for the A4988 it is impossible for us to know.
Do you know if there are A4988 other than with the "normal" 270 degrees trim potentiometer on the market?
Before you ask:
Did you really read and understand How to use this forum ?
AND:
Do you have already some solution or is a part of the problem sitting in front of the screen?  :)

raschemmel

#22
Aug 31, 2016, 02:39 pm Last Edit: Aug 31, 2016, 02:40 pm by raschemmel
Where does it say it is from Pololu ?


Quote
Hi, I have NEMA 16 motor and I connected it to A4988  
Quote
Do you know if there are A4988 other than with the "normal" 270 degrees trim potentiometer on the market?
Mine is 270 degrees, which is actually what I meant by "single turn" (my bad).

I rather doubt there is anything different out there.

batata004

@rpt007 thank you! My driver is original so your answer is great. I will test it in this weekend and come back here to tell you if I burned my motor or if I could calibraate it correctly :) No worry, I will do this at my own risk.

allanhurst

batata004   

You say the pot was very loose and you've tightened it up - it now should only move about 3/4 turn...


it's quite possible you've damaged it.

A multimeter would be very handy for finding out if this is true.

Anyway , good luck with your project.

regards

Allan

raschemmel

Quote
it's quite possible you've damaged it.
\

If you used any force at all to make turn after if stopped turning then it is damaged.
As stated , it should only turn 270 degrees. If it is turning more than that it is damaged.

jremington

Quote
Some of you are not as creative or resourceful as I, so you surelly need a multmetter, you need to pay a course to learn arduino, to learn programming
That certainly explains why I have been so confused at times!

rpt007

#27
Aug 31, 2016, 05:11 pm Last Edit: Aug 31, 2016, 05:11 pm by rpt007
Quote
That certainly explains why I have been so confused at times!
But you were at least able to measure the level of confuseness with your MM  :smiley-cool:
Before you ask:
Did you really read and understand How to use this forum ?
AND:
Do you have already some solution or is a part of the problem sitting in front of the screen?  :)

raschemmel

Quote
Some of you are not as creative or resourceful as I, so you surelly need a multmetter, you need to pay a course to learn arduino, to learn programming 
If you're so smart, why are you posting ?

batata004

#29
Aug 31, 2016, 06:05 pm Last Edit: Aug 31, 2016, 06:06 pm by batata004
Thank you guys, I thought yersterday that I had damaged my trimpot but after puting it gently in place it does not turn more than once. As some of you said, it probably turns no more than 300 degree so I hope I didnt break it yet.

I will try spin it CCW as you said and increase the current little by little and check if it works.

@raschemmel I am creative but I dont know everything, even with my whole creativity sometimes I need to ask to less creative people (but more inteligent at certain subjects) some advice.

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