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2-Axis Positioner

Which camera works? Where can you buy an adequate laser? And more...

Re: 2-Axis Positioner

Postby WalterMo » Tue Mar 20, 2012 9:15 pm

DeeboFitts wrote:Anyways, after unzipping it, it shows a .pde file format. What program do you use to open this?

To open the 'Positioner_Mats1.pde' you need to download the free Arduino Software to your PC:
http://arduino.cc/hu/Main/Software

To upload my code to an Arduino Uno or an Arduino Duemilanove you have to connect the Arduino board via an USB cable to your PC, choose below 'Tools' the type of board that you use and click on 'Upload'.

Walter
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Re: 2-Axis Positioner

Postby benoy » Mon Apr 16, 2012 3:34 am

Dear WalterMo,
You have mentioned that the power supply for the 2 axis positioner as 9 volts. What is the amperage that is needed? I am almost completing my 2 axis positioner.
Thankyou

Benoy
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Re: 2-Axis Positioner

Postby WalterMo » Mon Apr 16, 2012 10:19 am

Hello Dr. Benoy,

The current depends on the stepping motor's coil resistance. The maximum current which is rated in the data sheets of the motors is of course not necessary because the loads are nearly negligible. Only the horizontal motor will „notice“ a load, the attached gear (if you have used one).

So I would say: About 0.8 Amp for the bigger motor and 0.4 Amp for the smaller one.
The values are the total currents for both coils of each motor. Best if you measure it in fullstep mode and standstill or at a low speed.

Walter

PS. Can you post a photo of your 2-axis positioner?
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Re: 2-Axis Positioner

Postby benoy » Mon Apr 16, 2012 12:45 pm

Sure WalterMo,
I 'll post the turn table as soon as it is ready. You know Walter I live in a lazy town at the southern tip of India. The land is known as Kerala and my town is Muvattupuzha. Here every thing happens at a slow phase. This explains why it is getting delayed. Any way it is good to live here.

Regards

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Re: 2-Axis Positioner

Postby dickda1 » Sun Jun 03, 2012 6:33 am

I just built this project on a breadboard and really like it. I am using the phigets 1:99 gearbox and with 1.8 degree stepper for vertical axis. Pololu controller is adjusted for 0.4 ampere and seems to work initially without a heat sink. Hardware successfully receives the "Z" byte sent from the TestCom6 routine. I am planning to use this as practice for Walter and Sven's planeless scanner.

Thanks as usual to WalterMo and Sven! :D

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Re: 2-Axis Positioner

Postby tommyken » Mon Jun 25, 2012 9:59 am

Hello,

I wonder if there is a video about this piece of work. Can this be only used for modelling? Does it also rotates up^side down ? That laser is it horizontally or vertically mounted...
Can it be used in order for p.e. a statue ?

thx
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Re: 2-Axis Positioner

Postby tommyken » Tue Jun 26, 2012 8:49 pm

How does the laser reacts to the object ? That one to be scanned.
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Re: 2-Axis Positioner

Postby ddstech » Mon Sep 24, 2012 2:19 am

WalterMo wrote:@ddstech,

To your questions:
1. If you have adjusted the axis precisely in that way as DAVID is working, you can set the used angle increments in DAVID's Shape Fusion and DAVID will align the scans automatically. This feature was also working in former DAVID versions. The attached sketch shows how DAVID is using the 3 axis.

2. Stepping motors have some advantages over servo motors: They can do a certain number of defined steps without any feedback to the controller.
A servo motor is a DC motor with an attached gear and needs a feedback to the controller. This can be done in a servo loop which consists of a simple potentiometer at the gears output shaft or better, a high resolution optical incremental rotary encoder. And the incoming informations of the potentiometer or the encoder must be interpreted by an electronic circuit and forwarded to the DC motor.
My experience is, coming from that time when I tinkered with model boats, that servos like to jitter. Even if they should stand still. Of course there are good servos out there which are working well but its price is rather high.
It will be more difficult to let DAVID cause an axis to rotate for e.g. 45°. OK, the Arduino is also able to send pulses of differend widths to control a model-servo. But its resolution and precision is worse, compared with a stepper motor.

The stepping motors which I have used were lying around at home. A low-cost alternative could be:
For the horizontal motor (a gear isn't necessary):
http://www.phidgets.com/products.php?ca ... _id=3308_0

And for the vertical motor:
http://www.phidgets.com/products.php?ca ... _id=3301_0


Walter


Hi Walter,
I have this dual stepper motor controller shield for an Aruduino Uno (http://iteadstudio.com/store/index.php? ... cts_id=520) and am starting to get the hang of how to control the motors. With very limited electrical experience, I'm thinking that it would work in your setup as a replacement for the Pololu controllers. Am I correct? I think I can figure out the new wiring, but have no clue regarding amperage requirements, voltage, necessity of resistors, etc. Would you be willing to take a look at your wiring diagram and post a picture of it with the components crossed out that I wouldn't need? I will likely use the two stepper motors you suggested.

Also, do you happen to have a component list of the switches you used?

Thanks for your time,

ddstech
Camera: Point Grey Chameleon 1.3 MP Mono USB 2.0 camera
Lens: Fujinon DF6HA-1B Lens
Closeup lens on Camera: Carl Zeiss Ikon Proxar A28.5 .2m Close Up Lens
Projector: 3M 225a set to 1024x768
Projector closeup lens: +3 diopter closeup lens
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Re: 2-Axis Positioner

Postby WalterMo » Mon Sep 24, 2012 8:28 am

Hi,
I have just taken a look on this dual motor driver shield. It's fine and I didn't know it before. Its advantages are: Better (bigger) potentiometers to adjust the motor currents, stable screw clamps for the 2 x 4 motor wires. And the best: no connections between an Uno or Duemilanove are necessary to solder.

This board is a shield that will directly be hooked into the pins of an Arduino microcontroller. But unfortunately I have already occupied two pins (8 and 9) for the LCD display. The double motor driver board is using these for MS1 and MS2, means to set the step mode (full, 1/2, ¼ or 1/8) for one of the motors. On this diagram you see that I have used manual switches for both motors to choose the step mode and so to save (free) Arduino pins:
download/file.php?id=5203&mode=view

So what to do? I don't know. At present I don't have the time to reshape my circuit diagram and to change the Arduino code. Maybe someone else will do the modification. There are two other pins free on the Arduino: Pin 6 and the analog pin 5 which can be used as a digital outputs to control the LCD display.

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Re: 2-Axis Positioner

Postby ddstech » Mon Sep 24, 2012 2:20 pm

WalterMo wrote:So what to do? I don't know. At present I don't have the time to reshape my circuit diagram and to change the Arduino code. Maybe someone else will do the modification. There are two other pins free on the Arduino: Pin 6 and the analog pin 5 which can be used as a digital outputs to control the LCD display.


Thanks for looking it over, Walter. I can handle reworking the Arduino code and changing the wiring. Do I still need the 10k resistors and capacitors between the switches and motors?
Camera: Point Grey Chameleon 1.3 MP Mono USB 2.0 camera
Lens: Fujinon DF6HA-1B Lens
Closeup lens on Camera: Carl Zeiss Ikon Proxar A28.5 .2m Close Up Lens
Projector: 3M 225a set to 1024x768
Projector closeup lens: +3 diopter closeup lens
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Re: 2-Axis Positioner

Postby WalterMo » Mon Sep 24, 2012 4:23 pm

The electrolytic capacitors (470 and 680 µF) aren't necessary. The 10k and 1k resistors around the switches are important.

But now taking a closer look to all I recognize that there are not enough pins on the Uno available. D0 and D1 cannot be used at all. They are important for the COM communication. D2-D9 are used by the motor shield. D10 – D13 and the analog pins 0 - 5 are free for the positioner. These are only 10 ports. But we need 12 ports for controlling. :(
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Re: 2-Axis Positioner

Postby ddstech » Tue Sep 25, 2012 3:50 am

Would an LCD module like this one ( http://www.amazon.com/SainSmart-Serial- ... ay+arduino ) use fewer ports than your current design and free up the 2 extra ports I'd need?

Here's some product information on the above LCD module:
"As the pin resources of Arduino controller is limited, your project may be not able to use normal LCD shield after connected with a certain quantity of sensors or SD card. However, with this I2C interface LCD module, you will be able to realize data display via only 2 wires. If you already has I2C devices in your project, this LCD module actually cost no more resources at all. It is fantastic for Arduino based project."
Camera: Point Grey Chameleon 1.3 MP Mono USB 2.0 camera
Lens: Fujinon DF6HA-1B Lens
Closeup lens on Camera: Carl Zeiss Ikon Proxar A28.5 .2m Close Up Lens
Projector: 3M 225a set to 1024x768
Projector closeup lens: +3 diopter closeup lens
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Re: 2-Axis Positioner

Postby VDX » Tue Sep 25, 2012 7:05 am

... another project on my to-do list ... I have two RS232/I2C-LCD's (2 and 4 rows) and a spare Arduino Mega, so will use them for the UV-DLP-beamer setup ...

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Re: 2-Axis Positioner

Postby WalterMo » Tue Sep 25, 2012 7:43 am

@ ddstech

Yes, that seems to work. Good idea!

Here I found some more infos and a programming example:
https://arduino-info.wikispaces.com/LCD-Blue-I2C

It seems that only the Arduino analog input pins 4 and 5 are suitable for both serial bus signal lines:
http://www.arduino.cc/en/Reference/Wire

OK, then the 'Angle Increment' switch must be removed from pin 4 and connected to another analog input, maybe to pin 0. Here is the button 'Motor B up'. It is a digital signal, so remove it to maybe pin 13 where a display pin was. And remove the 'Reset' button from pin 7 to pin 12.

I am very curious about your progress.
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Re: 2-Axis Positioner

Postby ddstech » Tue Sep 25, 2012 3:37 pm

@ WalterMo

Thank you very much for your help and advice! The extra information you posted will be incredibly helpful. I'm learning how these things work as we go along, so now I'll try to patch it all together.

And thanks again for pioneering the 2-axis positioner and sharing your work on this forum!
Camera: Point Grey Chameleon 1.3 MP Mono USB 2.0 camera
Lens: Fujinon DF6HA-1B Lens
Closeup lens on Camera: Carl Zeiss Ikon Proxar A28.5 .2m Close Up Lens
Projector: 3M 225a set to 1024x768
Projector closeup lens: +3 diopter closeup lens
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