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Edgy Motor Control

JimboZA 4 years, 11 months ago

Morning.... when will this be available? Looking forward to getting one!

 

Jim

Stefan Hermann 4 years, 11 months ago

Stefan Hermann

Hi Jim,

thank you for the question. By now we are still in the production process and don't know, when exactly we will be ready :/

Best,

Stefan

JimboZA 4 years, 11 months ago

Thanks Stefan... and btw, do you have any idea for what other Edgies will be considered?

 

Jim

JimboZA 4 years, 10 months ago

I so want an Edgy MC.... do you know when they will be available?

Stefan Hermann 4 years, 10 months ago

Stefan Hermann

Hi Jim,

 

it is not so far by now, but send us an email and we will find a sollution ;)

<p>info@fritzing.org>

 

Best,

 

Stefan

Camaropower 4 years, 5 months ago

Hi,

I searched Fritzing and Arduino for use of the l293er with microstepping code but didn't find any. Because I'm new to the field and got an l293e running with full step, I don't know how to do that. I noticed this edgy has a l293dd on it. How would I use it with microstepping (>1/16)? What will the code has to look like?

If it's possible to use the edgy with microstepping I will buy it right away!

Stefan Hermann 4 years, 5 months ago

Stefan Hermann

Hi Camaropower,

what do you want to do? Do you use a stepper motor? What do you mean with full step?

Best,

Stefan"

Camaropower 4 years, 5 months ago

Hi,

yes I want to controll a stepper motor, actually in the end there will be two of them.

I have a running model with an arduino mega2560, a l293e and a KP39HM4 (Matsushita) Stepper with 3.6 deg per step. This is working fine. I can controll the speed and direction. But I just managed to do full steps, each 3.6°, which is to rough for my purpose.

I would like to drive this motor and some other with at least 1/32 or 1/64 step what makes 0.1125° (0.05625°) per step. 6,75 arcminutes per step or better smoothes the sine and doesn't procude so much kicking to the gears which are mounted as you can read below.

Background: Telescope trackingsystem for a 24" telescope on a tight german mount with existing motors, gears etc. It has to run on Linux, because of the accuracy and the imaging pipeline running there, too.

My problem is, that the tracking controll which is mounted to the telescope right now uses stuff from the beginning 70th and was programmed in the beginning 90th. Those days, CCD cameras didn't have so much pixels as they do today. The camera we have on hand is an Apogee Ap7p from 1996 which resolution is high enough that it resoluts the errors of the trackingsystem. We got jumps in the scale of 4 to 7 arcseconds on the images so they can't be used for scientific analysis because stars get eggy and objects like galaxies more fuzzy than they were.

The solution is, leaving that old stuff behind and builing a new tracking system which does autoguiding to correct the hopefully reduced errors.

The first approcches used a robotikboard with to l298ers and plenty more options for additional sensors, but this board doesn't have interfaces like usb or ethernet, we stalled it for later when there is more time. So I decided to have a quick'n'dirty version with arduino because firmata sounded so nice and here I am.

I know that there could be a way of driving the microstepping with pwm, but I do come from a different part of computer science so I do not have the expertise yet. I was writing image analysis software and got along with gui programming lately. In university I had some experiences with microcontrollers on a very low level (pic-based, programmed in assembler). So I need help.

Summarize:

I want to controll a the stepper metioned about with a l293e, an arduino mega2560 with pwm in 1/32 or 1/64 step mode maybe higher.

Camaropower 4 years, 5 months ago

If the edgy shield helps me doing that, I'll get the it.

Sorry for the typos in the last sentences, was a little instable here.

Stefan Hermann 4 years, 5 months ago

Stefan Hermann

Ah, I see. Unfortunately, the Edgys are not tested for microstepping. But there is a very good motor shield which cames with it's own microstepping enabled library: http://www.ladyada.net/make/mshield/

Camaropower 4 years, 5 months ago

Hm, I think the shield isn't the problem here. lady ada ist using l293d here which is similar to the l293e or the dd you are using on the edgy. The edgy is nothing else than a l293 on its own board with the wiring in good place. I took a closer look at the schematics and the board view in fritzing.

So, I think the programming is the main problem. I never wrote a pwm with microstepping before and I don't know how to do it with the arduino stepper lib. Any hint on that?

Camaropower 4 years, 5 months ago

Hi,

I dug into lady ada's motor lib to see how one can use it for microstepping. I found in the constant speed example // you can change these to DOUBLE or INTERLEAVE or MICROSTEP!
void forwardstep() {
motor1.onestep(FORWARD, SINGLE);
}
void backwardstep() {
motor1.onestep(BACKWARD, SINGLE);
}
I will have a try on that one and later take a look at how the code in the lib looks like. Maybe this is just what is was looking for. Thanks for the hint with ladyada. I found that side two weeks ago to but didn't look very closely.

Is the edgy motor shield ready yet?