Arduino Forum

Using Arduino => General Electronics => Topic started by: batata004 on Aug 30, 2016, 11:08 pm

Title: Trimpod with step motor A4988
Post by: batata004 on Aug 30, 2016, 11:08 pm
Hi, I have NEMA 16 motor and I connected it to A4988 so I can control the motor to arduino. The problem is that there is a trimpod in the drive A4988  and many people say I should first set a precise current using the trimpod to avoid damaging the module.

I saw many tutorials online and they look too complicated and I dont even have a multimeter. So my idea is this: could you please tell me which wise (clockwise or anticlockwise) the trimpod reduce and increase current?

My idea is this: I will turn the trimpod in the clockwise/anticlockwise many times so I decrease the current to a minimmum. After that I will turn on the motor and see if it spins. If it does not, I will turn the trimpod and increase the current till it starts moving so I know I am not abusing the current.

But first I need to know: do I need to turn the trimpod clockwise or anticlockwise in order to make this module A4988  have the minnimum amount of current?
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 30, 2016, 11:15 pm
Seriously, if you are too cheap to buy a motor you should find another hobby. A DMM is the FIRST investment you should make when you get into this hobby. Mow the neighbor's lawn or sell lemonade or something, but buy a DMM (Digital MultiMeter).
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Aug 30, 2016, 11:47 pm
It's not about money man... if anyone could tell me which wise to spin the trimpod it would be much easier than using a multimeter... hope someone can check that to me.
Title: Re: Trimpod with step motor A4988
Post by: MarkT on Aug 31, 2016, 12:04 am
trimpot, not trimpod.  trimmer-potentiometer.

Buy a small cheap multimeter now, then take time to choose a better one later if
you want.  You cannot do electronics with no eyes!  A meter is your eyes.  Well, a
'scope is really your eyes, but for DC and sinusoidal low frequencies a meter is usually enough.
Title: Re: Trimpod with step motor A4988
Post by: ChrisTenone on Aug 31, 2016, 12:14 am
A trimpod is an iPod that works out.

A trim pot does not regulate current, but it can be used in a circuit to do so. It is a variable resistor. You can probably look at the construction of yours and determine which two leads are the ends of the resistor, and which one is the wiper.

There is no standard, so there is not a correct direction that applies to all potentiometers.
Title: Re: Trimpod with step motor A4988
Post by: MarkT on Aug 31, 2016, 12:21 am
Technically a potentiometer is a 3 terminal device, a variable resistor is a two terminal device.
The wiper is the metal bit the adjustment tool engages in, its easy to stick a multimeter
probe on it, but not while its actually being adjusted, unless you can hold the probe to the
jewellers screwdriver while you adjust it (yes, usually these trimmers are too small for anything
else).

In a high voltage or RF circuit you use a special plastic tool for adjusting trimmers.
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 31, 2016, 01:05 am
That's all well and good but I've done that A4988 current calibration several times and you need to be able to measure the current through the motor winding WHILE measuring the voltage at the test point, neither of which you can do without a multimeter. I used the power supply current display on the P.S. LCD  while measuring the voltage with a meter.

Good luck calibrating that without a meter.
Title: Re: Trimpod with step motor A4988
Post by: jremington on Aug 31, 2016, 02:41 am
Quote
if anyone could tell me which wise to spin the trimpod it would be much easier than using a multimeter... hope someone can check that to me.
NO ONE can tell you how to set it.

Buy a multimeter. You will learn something by using it. Otherwise, choose another hobby.
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Aug 31, 2016, 03:18 am
I HAD AN IDEA! Just please tell me this: if I turn a trimpot 100x times to one side, will I have to run it 100x times to another side so it comes back to its original value? Or if I turn it after certain point, the trimpot will not care anymore about now many turns did I make? For example: after 3 turns, if I make 10 or 1000 turns, the trimpot will not change its value anymore, and if I turn it to the other side once, it will already change the current?

Cause I am thinking about turning the trimpot 20 times to one side and pray that this side is the 0 current side (if not, I will burn my drive so at least I know now the right side) so I can turn it slowly to the other side till the motor moves. Can I do that?
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 31, 2016, 03:25 am
It's a single turn trimpot so that probably won't work. (at least mine was)

Based on your reply to jremington's post you probably should choose another hobby.
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Aug 31, 2016, 03:42 am
Hey guys I just found this link and the guy had the same idea as me: http://rigidtalk.com/wiki/index.php?title=Stepper_Driver_Adjustment

Quote:

Method 1 - Empirical Adjustment:
The stepper drivers can be adjusted without measuring voltages, by observing motor performance. Use a nonmetal screwdriver (plastic or ceramic) to avoid short circuits. Either run a print (preferably one that's been causing motor issues) or set up manual control using an LCD Controller, or Repetier Host, or Pronterface. CAREFULLY turn the pot fully CW (minimum current) then back CCW about 1/4 turn, or enough to make the motor run smoothly. From that point, if you are able to adjust while the motor is moving (either in a print or under manual control) turn the trimpot CW until the motor starts to stall or stutter, then turn CCW until steady performance resumes. Otherwise, alternate adjusting the pot slightly and then running the motor, with the same results in mind. The general idea is to find a low current setting that results in stalling or stuttering, and then boost the current a bit to get reliable motion without going too far CCW.



BUT I need to make sure CW or CCW decreases or increase current cause in this link the guy makes reference to another driver! Any guess?




Sincerally, I think this method is the BEST ALTERNATIVE. Better than using a multemeter as many of you said. Every motor has internal firction which differs from each other. So using a multmetter is not ideal cause you will not have equal motors. I think that increasing the current little by little till you find the sweet spot is the best way to do this. You dont need to rely in resistor values, VREF, information taken from datasheets... you can do this empiraclli.

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.
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 31, 2016, 04:07 am
The fact that you persist in ignoring the recommendation to buy a meter and then have the gall to tell us you think this method is BETTER  than actually MEASURING the current ( and voltage) confirms that your future in electronics will be fraught with problems. I can only say this does does not say anything good about your judgement . The fact that the A4988 will work right out of the box without doing the calibration is not the point. Whether or not you can adjust the pot to some point that allows the motor to work is also not the point. The point is that in your inexperience and twisted logic you actually think that doing the calibration blindly is better than measuring the parameters in question is what sends a red flag about your judgement. Had you simply stated, "I need to be able to use the motor immediately so I'm going to adjust the pot to some arbitrary value where the motors will work and then buy a meter at the first opportunity" there would be nothing wrong with that. It's your outright refusal to buy a meter and insistence on calibrating it without one and at the same time saying you think it's better not to use a meter that puts your judgement in question.  
Title: Re: Trimpod with step motor A4988
Post by: MorganS on Aug 31, 2016, 04:59 am
If you are in the USA then Harbor Freight is almost everywhere and they have a DMM that is good enough for $6. Sometimes it is on sale for $3 or less.

If you are somewhere else in the world then look for a discount tool store. You should only buy the cheapest multimeter that measures volts and ohms. It does not have to be digital although those are now much cheaper than analog. That is all that is necessary for this job and many other jobs in your future.
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 31, 2016, 05:08 am
If at all possible you you try to get a DMM with current mode.
Title: Re: Trimpod with step motor A4988
Post by: ChrisTenone on Aug 31, 2016, 07:53 am
I think the set screw is loose on the knob on your pot.
Title: Re: Trimpod with step motor A4988
Post by: allanhurst on Aug 31, 2016, 08:54 am
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.
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Aug 31, 2016, 01:44 pm
@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.
Title: Re: Trimpod with step motor A4988
Post by: rpt007 on Aug 31, 2016, 02:10 pm
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 (http://forum.arduino.cc/index.php?topic=415724.0)
Title: Re: Trimpod with step motor A4988
Post by: pwillard on Aug 31, 2016, 02:16 pm
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.  
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 31, 2016, 02:35 pm
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.
Title: Re: Trimpod with step motor A4988
Post by: rpt007 on Aug 31, 2016, 02:36 pm
@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 ...
Title: Re: Trimpod with step motor A4988
Post by: rpt007 on Aug 31, 2016, 02:39 pm
@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?
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 31, 2016, 02:39 pm
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.
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Aug 31, 2016, 03:40 pm
@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.
Title: Re: Trimpod with step motor A4988
Post by: allanhurst on Aug 31, 2016, 03:53 pm
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
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 31, 2016, 04:18 pm
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.
Title: Re: Trimpod with step motor A4988
Post by: jremington on Aug 31, 2016, 04:55 pm
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!
Title: Re: Trimpod with step motor A4988
Post by: rpt007 on Aug 31, 2016, 05:11 pm
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:
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 31, 2016, 06:03 pm
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 ?
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Aug 31, 2016, 06:05 pm
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.
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 31, 2016, 06:06 pm
Quote
it probably turns no more than 300 degree
No. We said 270 degrees.
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Aug 31, 2016, 06:12 pm
@raschemmel I am checking and mine is turnin around 300 degree not 270. Maybe it's indeed broken, but I will have a try with it when I get to my shop and get the motor to test.
Title: Re: Trimpod with step motor A4988
Post by: jremington on Aug 31, 2016, 06:48 pm
Quote
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.
Isn't it amazing  that a simple trimpot can be such a major stumbling block?
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 31, 2016, 09:10 pm
Quote
Isn't it amazing  that a simple trimpot can be such a major stumbling block?
I believe if you use a meter to monitor the voltage the calibration can be done in under a minute.
Title: Re: Trimpod with step motor A4988
Post by: allanhurst on Aug 31, 2016, 09:27 pm
Hi batata004

Just because people have specialist knowledge doesn't mean they're not very creative ( whatever that means)...

I hope we've been able to help.

regards

Allan.
Title: Re: Trimpod with step motor A4988
Post by: jremington on Aug 31, 2016, 09:52 pm
A creative person could probably change an automobile tire using a screwdriver, but I suspect that use of the right tool can make most jobs a bit easier.
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Aug 31, 2016, 09:56 pm
Yes, a creative person can do A LOT of things while inteligent people can do only a few things well done. You dont need an astronaut or a PHD in mechanics to change an automobile tire, you can get your screwdriver and solve the problem by yourself.
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Aug 31, 2016, 11:07 pm
Quote
A creative person could probably change an automobile tire using a screwdriver, but I suspect that use of the right tool can make most jobs a bit easier.
When I was canyon racing in Southern California I got a flat on my Yamaha FJ-1100 and had to repair the tire (with a Vulcan tube repair kit) and I was wearing full leathers on a hot summer day. I took off my jacket and was trying to get the tire back on the rim after repairing the tube and I was having trouble getting the tire onto the rim. Just then some other canyon racers came around the corner and stopped to help. One of them suggested I use suntan lotion to lube the rim and that made all the difference in the world. I was back on the road in 10 minutes.


Quote
You dont need an astronaut or a PHD in mechanics to change an automobile tire, you can get your screwdriver and solve the problem by yourself.
FYI,
This  (https://www.google.com/search?q=tire+removal+tool&rlz=1C1GPCK_enUS504US504&biw=1058&bih=815&tbm=isch&imgil=-BIZZjW9VMuBAM%253A%253Bb9T0jmHqOM3DfM%253Bhttp%25253A%25252F%25252Fwww.ebay.com%25252Fbhp%25252Ftire-changing-tools&source=iu&pf=m&fir=-BIZZjW9VMuBAM%253A%252Cb9T0jmHqOM3DfM%252C_&usg=__nM6p3sTGROMs5KIzvXXZqG1XGfs%3D&ved=0ahUKEwjWnPu5yOzOAhVO4WMKHQnxAfkQyjcITw&ei=y0fHV5aLFs7CjwOJ4ofIDw#imgrc=9W68oLPIGBrjHM%3A) is the tool I needed . (I didn't have a screwdriver)
Title: Re: Trimpod with step motor A4988
Post by: jremington on Aug 31, 2016, 11:21 pm
Quote
Yes, a creative person can do A LOT of things while inteligent people can do only a few things well done.
Are you still having trouble with that trimpot?
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Sep 01, 2016, 12:04 am
@jremington probably not, in the weekend I will check it out and see if it works. If not, I will come back here to ask suggestion from not creative but inteligent people of this forum who always try to help; sometimes in a inteligent way and other times in a creative way - which I prefer more.
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Sep 01, 2016, 12:57 am
Quote
from not creative but inteligent people of this forum  
If you are so creative , how many patents do you have ?


US PATENT 4088315 (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4088315.PN.&OS=PN/4088315&RS=PN/4088315)
Title: Re: Trimpod with step motor A4988
Post by: rpt007 on Sep 01, 2016, 01:02 am
Being creative AND intelligent must not be a contradiction.
I like this combination most, because it is way better than being stupid AND creative
Title: Re: Trimpod with step motor A4988
Post by: ChrisTenone on Sep 01, 2016, 01:09 am
How many patents do you have ?


US PATENT 4088315 (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4088315.PN.&OS=PN/4088315&RS=PN/4088315)
Weirding device ala movie version of Dune?
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Sep 01, 2016, 01:10 am
I prefer being stupid and creative than inteliggent cause inteligent people does exactly what @raschemmel just did, so they become an idiot in a blink of eye.
Title: Re: Trimpod with step motor A4988
Post by: ChrisTenone on Sep 01, 2016, 01:17 am
... So my idea is this: could you please tell me which wise (clockwise or anticlockwise) the trimpod reduce and increase current?
...
It depends on how you have it wired up! A trim pot works like this: A resistor film is attached to the two outer pins. The center pin is free to connect to the resistor at any point along the resistive field. The resistance between the center tap (aka the wiper) and each of the end pins will add up to the total resistance of the end-to-end value.


                               |
                               V
          ---------/\/\/\/\/\/\/\/\/\/\---------


So if you hook up the center and left pin, it will increase the resistance as you move it to the right. If you hook up the center and right pins, it will behave in the opposite way.





ps, I would rather be an idiot savant than a genius savant.
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Sep 01, 2016, 01:30 am
@Cris Tenone,

Quote
Weirding device ala movie version of Dune?
 
It's actually just a life size 3-dimensional karate dummy with pressure sensors mounted on a shaft driven by a differential attached to a high torque motor so when you step on the pressure sensitive floor it knows where you are and can track you (rotating) as you walk around it.. The joints are functional and have "push to move, release to lock" buttons so you can move any limb to set it into any fighting stance. and computer control to measure the strike impact force and a time domain impact printout that prints out a card with the instructor's impacts as red dots and the student's impacts as black dots with targets listed from top to bottom and time shown from left to right so you can tell the impact and timing difference between two tenth degree black belts . There is also a life size display (there were no led flat panels in 1976) with lights behind it so everyone can see the impacts illustrated on the display panel when someone is executing a routine. There is a "Non-Lethal" <--> "Lethal" select switch to trigger alarms if a strike is inconsistent with the switch setting. Cameras can be programmed to snap a picture if a strike meets some criteria.
Title: Re: Trimpod with step motor A4988
Post by: Wawa on Sep 01, 2016, 02:02 am
@ batata004
How many posts will it take untill you realise that you can build things without a DMM, but not fix or adjust them. Human beings can't see voltage or current, so we need tools for that.
For >=$25.00 you get an average hobby DMM with good accuracy and longer battery life.
Ignore the small/cheap $10 ones.
Look after it, and you will have it for many years.
Soon you will realise you can build better/faster, because you know exactly what you're doing.
This might help.
https://www.pololu.com/blog/484/video-setting-the-current-limit-on-pololu-stepper-motor-driver-carriers

@rashemmel.
Don't you think it's time you started acting like an adult.
We all value your technical contributions, but not the mud-slinging.
Leo..
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Sep 01, 2016, 02:07 am
@Wawa,


Quote
@rashemmel.
Don't you think it's time you started acting like an adult.
We all value your technical contributions, but not the mud-slinging.
What do you call what the OP was doing ? If we are going to set examples , how about we tell the OP he shouldn't be calling people idiots, for starters. Did anyone call him an idiot ? (if so, please quote )
How about telling the OP  "It is not good form to call other forum members an idiot"

How about "Let's keep it civil ..."

Where is that statement ? You jump all over my case when all I did was respond to the OP's comment.
(below)

Quote
I prefer being stupid and creative than inteliggent cause inteligent people does exactly what @raschemmel just did, so they become an idiot in a blink of eye.
I deleted my previous remark out of respect for your opinion but in all fairness I think you should address the source of the mud slinging before addressing the reaction. If you are going to represent the "voice of reason" then it is only fair you address the OP's remarks. Why are you not asking him to refrain from mud slinging ? Is that fair ?
Title: Re: Trimpod with step motor A4988
Post by: Wawa on Sep 01, 2016, 03:58 am
Yes, you're right. I should have included OP and maybe others for throwing fuel on the fire.
Leo..
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Sep 01, 2016, 04:29 am
@Wawa kkkk :)

@ChrisTenone great explanation man, so it's just like a potentiometer. Why did they have to use a different name trimpod? So, visually, if I can see where is GND and where is VCC connected to this trimpot, can I know which way should I rotate the knob to increase/decrease current?

Title: Re: Trimpod with step motor A4988
Post by: Wawa on Sep 01, 2016, 04:54 am
so it's just like a potentiometer. Why did they have to use a different name trimpod?

So, visually, if I can see where is GND and where is VCC connected to this trimpot, can I know which way should I rotate the knob to increase/decrease current?
A trimpot is just a potentimeter, but only constructed to adjust a limited amount of times during "trimming" of the circuit. After adjustment it's sometimes "glued" in place with lacker or nail polish.
Also great to see if the user has fiddled with settings in the warranty period.

Yes, but it's so much better to directly adjust for the right voltage.
Remember that you only have a limited amount of chances to get it right.
Then you have to replace the trimpot.

If you have the Adafruit board, you should watch the video in post#46.
It explains what voltage to adjust to, and which way to turn the pot.
Leo..

Title: Re: Trimpod with step motor A4988
Post by: ChrisTenone on Sep 01, 2016, 05:39 am
... Why did they have to use a different name trimpod?
...
nobody calls it a trimpod.
Title: Re: Trimpod with step motor A4988
Post by: ChrisTenone on Sep 01, 2016, 08:05 am
Here are some potentiometers:
(https://dl.dropboxusercontent.com/s/cl6afinkik8kpd5/pots.gif)

The one on the right is actually a trimpot. You need to use a tool to turn it. The one on the left is what you appeared to be describing. It is a ten-turn, precision, potentiometer, possibly used to fine-tune some instrument. The one in the middle may be similar to the one you have. They are all 'topologically' and functionally similar, but they differ in their strengths and best uses. There are lots of other forms.
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Sep 01, 2016, 02:50 pm
@ChrisTenone wow I didnt know that! So they are all similar but they have different applications with different precisions and size. At least now I know that a trimpod (I just use d to set fire in people who cant handle a stupid person) is just like any other potentiometer and it's not complicated, I just need to know which terminal is GND and which is VCC so I know which direction I should turn it to increase/decrease current.
Title: Re: Trimpod with step motor A4988
Post by: pwillard on Sep 01, 2016, 02:52 pm
My god.

It is a a trimpot.... not a trimpod.

Trimmer Potentiometer...    TRIMmer POTentiometer... Trimpot.

Use the right word or we will continue to treat you like *you* are dumb.
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Sep 01, 2016, 02:56 pm
@ChrisTenone did see you what I said?  ahuahauha this proves @pwillard didnt even read what I said.
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Sep 01, 2016, 03:14 pm
Quote
At least now I know that a trimpod (I just use d to set fire in people who cant handle a stupid person)  
Does explain your inability to spell the word "intelligent" ?

Quote
I prefer being stupid and creative than inteliggent cause inteligent people does exactly what @raschemmel just did, so they become an idiot in a blink of eye.
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Sep 01, 2016, 03:23 pm
@raschemmel if had fluent speech in 3 languages you would know why I wrote "inteligent".
Title: Re: Trimpod with step motor A4988
Post by: rpt007 on Sep 01, 2016, 04:12 pm
Quote
Why did they have to use a different name trimpod?
Because a "normal" potentiometer is the one you use(d) in a radio, amplifier etc. to increase volume (with a turning knob attached). Inside of such a radio (at least some years/decades ago, when everything in a HiFi sytem worked analogue) you will find a lot of trimming potentiometers which only can be operated using a small screw driver (only the luxury version might come with a tiny knob attached).

Those little internal adjustment devices are called trimpots (as abbreviation of trimming potentiometer) as they trim frequency, voltage, current, you have it.

Quote
So, visually, if I can see where is GND and where is VCC connected to this trimpot, can I know which way should I rotate the knob to increase/decrease current?
Mightbe yes. But I would not go that path without exactly knowing what the whole circuit does when the value of the trimpot is lowered or increased - it's all depending how the whole circuit around the main chip is designed.

At this point I leave the point with the MM - everything is said to that.
Title: Re: Trimpod with step motor A4988
Post by: batata004 on Sep 01, 2016, 04:15 pm
I said I am a fluent at speech your idiot. I am used to hear and talk in english, not writing. You should read better what people say @raschemmel SPEECH != WRITING

Ayway, if my english was not good, this thread wouldnt have gone so far with so many people helping.

@raschemmel you just proved you are not creative and not inteligent, maybe you are in a limb where you are just a regular guy, a typical Joe. Congrats, you are like 99% of population. Now go f*** yourself as 99% of people do daily in their terrible underpaid jobs because they are just one more "Joe".
Title: Re: Trimpod with step motor A4988
Post by: rpt007 on Sep 01, 2016, 04:28 pm
@batata004 et al:

I think, we should not spoil the good mood in this forum.
So pls to whom it may concern: let's stop this kind of personal attacking and get back to a technical "Arduino level".

If not, I am out of this thread.
Title: Re: Trimpod with step motor A4988
Post by: raschemmel on Sep 01, 2016, 04:31 pm
Sorry for the misunderstanding.

In that case the forum software has a built in spell checker that will help you.
If you edit the post that contains this :
Quote
I prefer being stupid and creative than inteliggent cause inteligent people does exactly what @raschemmel just did, so they become an idiot in a blink of eye.
You will see that in edit mode the misspelled words are underlined red. If you right click on those the correct suggestions appear on a pop up menu.
(FYI)
I don't see anything to be gained by intentionally misspelling words (like "Trimpod" in your post title).  I would think that would just compound the language barrier. As far as the "speech"/"writing" issue, I help forum members in France, Italy and Germany on the international forum using Google Translate and I can't speak any of those languages. (just sayin') The forum spell checker should solve most of your spelling issues.


Quote
Ayway, if my english was not good, this thread wouldnt have gone so far with so many people helping
As I see it , this thread has gone on so long because you have (since the beginning) , refused to buy a meter to measure the voltage using the Pololu tutorial video.  There is no other explanation for a post about a trimpot lasting so long. The calibration would have taken 1 minute with a meter.
Instead we are dragging this out debating whether or not it is possible to calibrate a Pololu A4988 Stepper (NOT "step") Driver without using a DMM. Turn it too far one way and your motor doesn't get enough current. Turn it too far the other way it could get too much.

Remember this ? (Reply#2) (We're now on Reply#61)
Quote
It's not about money man... if anyone could tell me which wise to spin the trimpod it would be much easier than using a multimeter... hope someone can check that to me.
Almost all of the posts in this thread are about why you should use a meter. By your own admission you can afford it. So how long we going to go around in circles ?

I think the Global Moderater should lock this thread.
Title: Re: Trimpod with step motor A4988
Post by: Wawa on Sep 01, 2016, 11:59 pm
@raschemmel you just proved you are not creative and not inteligent, maybe you are in a limb where you are just a regular guy, a typical Joe. Congrats, you are like 99% of population. Now go f*** yourself as 99% of people do daily in their terrible underpaid jobs because they are just one more "Joe".
I think a moderator should lock this thread AND ban batata004 untill he grows up.
Leo..
Title: Re: Trimpod with step motor A4988
Post by: ChrisTenone on Sep 02, 2016, 05:27 am
Reply #59 is out of line.