24BYJ Motor speed

[Anonymous]

Started this subject on the blog https://www.marginallyclever.com/blog/2013/08/how-to-build-an-2-axis-arduino-cnc-gcode-interpreter/#comments and per Dan’s suggestion will continue here.

My setup is the following:

– Code as per “How to build an 2 axis…” tutorial https://www.marginallyclever.com/blog/2013/08/how-to-build-an-2-axis-arduino-cnc-gcode-interpreter/#comments
– Arduino Uno
– Two Steppers 24BYJ http://www.emartee.com/product/41426/
– Dual L293 Motor Shield https://www.marginallyclever.com/shop/control-boards/dual-l293-motor-shield

Everything works fine but at a relatively slow speed and the FXXX feed speed doesn’t seem to make any difference, from F100 to F10000.

Dan: on the blog you said “…you may be hitting their top speed already…” but when I drive the motor using an Sparkun EasyDriver https://www.sparkfun.com/products/retired/10267 it runs much faster.

Any ideas will be appreciated. (i’m relatively new to the stepper motors world…)

Thanks

[Anonymous]

I think there’s something crippling top speed in firmware_ams. I ran some tests friday and found that every speed setting had the same speed at the pen tip. I have to investigate further.

Two house points to whoever figures it out before me 😉

[Anonymous]

I guess I found where the problem is. And even though I didn’t came out with an elegant solution at least it works fine for me now.

What I did was:

– comment the “tick()” function call on both instances of the “line” method
– replace them by “delay(X)”

then I played around with X until I found the right speed (4) for my motor/application.

Hope it helps….

[Anonymous]

try delayMicroseconds(), which has a better resolution. delayMicroseconds(3500) is the same as delay(3.5).
Difference is
a) delay() can’t do fractions.
b) delayMicroseconds only works up to ~16000 microseconds.

[Anonymous]

Thanks, works fine!

Can you please add the “arc” function to your code? I have seen your post about it but tit doesn’t compile and instead of cleaning it up myself I thought you will do it much faster/better than me (lazy me…) 🙄

Thanks again

[Anonymous]

I’m currently in mexico on vacation, without hardware to test.
If you can wait a week, I might be able to get one in.

The dev branch of Makelangelo has G02 and G03 arcs.

[Anonymous]

how come you didn’t take you CNC along on your vacation?

Viva Mexico! Have one (or more) tequilas on me…

[Anonymous]

I’m kicking myself for not bringing
(a) a quadcopter to film the hotel
(b) an arduino starter kit to write tutorials

Ah well, I’ll keep busy trying to write a voronoi tessellator for Makelangelo.

[Anonymous]

Hi Dan, hope you had a good break and have your batteries fully reloaded…

I’m still interested in having the “arc” function added to your basic GCode sketch, can you please help with it?

Many thanks!

[Anonymous]

Hi Dan, following your suggestion I have been trying to add the arc function to your “2-axis Arduino CNC Gcode Interpreter”. This path seems to be more easy than removing what is not needed from Makelangelo code. Anyway it seems my Arduino/Math skills are not strong enough to make it work 🙁 , could you please give me (and other) a hand and release a new version adding the Arc method?

Many, many, thanks in advance….

[Anonymous]

I’ll see what I can do.

[Anonymous]

check the gcodecncdemo2v1 and v2, both should have arc() now.

[Anonymous]

Dan, may thanks, will test later but i guess I’m now good to go on my own…

Cheers!

[Anonymous]

Dan after spending a couple of hours with the new version I have the following comments:

1 – The HELP message for arc
F(“G02 [X(steps)] [Y(steps)] [I(steps)] [J(steps)] [F(feedrate)]; – clockwise arc”)
doesn’t match the method implementation
arc(float cx,float cy,float x,float y,float dir)
in other words the X,Y and cx, cy parameters are interchanged

2 – If I’m getting it right the following commands should give me the same result: a straight line from X100, Y00 to X-100 Y00:

// USING LINE
G92 X00 Y00;
G00 X100;
G00 X-100;

//USING ARC
G92 X00 Y100;
G00 X100;
G02 I00 J00 X-100 Y00;

but this is not what I’m getting. There is no movement in the second case.

What am I doing something wrong?

NOTE: My motors are 2048 steps per turn

[Anonymous]

I’ll fix the gcodecncdemo and put them the right way around.

// USING LINE
G92 X00 Y00;
G00 X100;
G00 X-100;

Would be a straight line.

//USING ARC
G92 X00 Y100; <– Did you mean Y100?
G00 X100;
G02 I00 J00 X-100 Y00;

[Anonymous]

My wrong, should be Y00, sorry

//USING ARC
G92 X00 Y00;
G00 X100;
G02 I00 J00 X-100 Y00;

[Anonymous]

Dan, forget about the straight line question, I guess I got it wrong.
It seems I’m experiencing problems with they way the program drives the motors and that’s why I’m getting odd results. I have more digging to do.

Many thanks for your support.

Best.

[Author]

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