[Angel LM]

Hi Burcu!

I’m happy to know that the motors are working now, what was the problem?

Regarding the home position question, do you have any position sensor in your Thor? In my case (the current design in my repository), Thor has 5 sensors (on the 5 first articulations) to set the home position when the board is connected (or the $h command is sent).

If yours have not sensors this would the sequence:

• When the Arduino Mega is connected to the PC it assumes that the current position is the home position (A=0º, B=0º, C=0º… and so on)
• When the connection is established between the Arduino Mega and the GCode sender program, the current position is set as home position (A=0º, B=0º, C=0º… and so on) <- This happens everytime you close and open the serial connection
• When the connection is established and you send a GCode the motors will move considering the home position.

If it has sensors this would the sequence:

• When the
  Arduino Mega is connected to the PC the robot will start the home sequence, moving its articulations until them reach the home position (A=0º, B=0º, C=0º… and so on)
• When the
  connection is established between the Arduino Mega and the GCode sender
  program, the robot will start the home sequence, moving its articulations until
  them reach the home position (A=0º, B=0º, C=0º… and so on) <- This happens everytime you close and open the
  serial connection
• When the connection is established and you send a GCode the motors will move considering the home position.

In both cases, sending a single command should work…

Can you share the GCode you are trying to send? I’ll try to replicate the issue.

Just in case, there are a GCode command that switches between Absolute Positioning and Relative Positioning that may be the cause of that problem.

[Angel LM]

Hi Thalles!

Welcome to this community!
Regarding your questions:

I – What are the parameters of the step motors that you recommend for this project?

Do you mean the hardware specifications or the firmware configuration? If you are looking for the hardware specs, you can look at the Stepper Motors section in the Component List & Where to buy page at Thor’s wiki. If you are looking for the firmware configuration, you can check the GRBL source code.

II- I saw on some posts that people bought the PCBs from you. Are you still selling them? How much do they cost?

I still have a few ControlPCBs (just the PCB without the components) available, price is 10€ + shipping cost. At this moment I’m not selling either kits nor assembled boards

III- Could you please provide a list with all the recommended components to buy for this project please?

I think that you are looking for the Component List & Where to buy page at Thor’s wiki 😉

Hope it helps!
Ángel L.M.

[Angel LM]

Hi Adam!

In my case, I’m currently generating the gcode by hand. As I’m controlling the position using forward kinematics it’s pretty easy to write them in the text editor and save it as “.gcode”.
In my endless To-Do-List there is a point dedicated to develop a simple program to control it in real time using Inverse Kinematics and another one to generate a gcode after entering the desired coordinates and times.

As far as I know Smoothieboard allows to create a Robot profile and it is powerful enough to do the IK calculations, keep me informed if you use the Smothieboard and make that profile!

Best regards,
Angel LM

[Angel LM]

Hi Kathrin,

First of all, welcome to the family! I added you to the List of Thor Builders

As I said on previous occasions, I can’t be happier seeing that Thor is being used in schools and universities 🙂
I hope that you and your students like the project as much as I like it!

Do not hesitate on asking if you need some help!

I’ll be looking forward to see updates of your project soon 😉
Angel LM

[Angel LM]

Hi Adam!

I just updated the Sensor PCB component list at the Thor’s wiki. The model of this optocoupler (or “photo interrupter”, which I think it’s the correct name) is ITR9608.

Hope it helps!

[Angel LM]

Hi Martin,

I only have 1 PCB left. I can send you the PCB + Mats for 30€+Shipping cost
At this time I can’t offer the assembled and tested one as I don’t have enough time for it.

The mats include:

• PCB
• All male pins
• All female pins
• All resistors
• All leds
• All capacitors
• All terminal blocks
• The diode
• The fuse

And it does not include:

• Arduino Mega
• Drivers
• Wires
• Motors
• Fans
• Sensors

Best regards,

Ángel LM

[Angel LM]

Hi Adam!

This is the kind of optocouplers i’m using. I’m not sure about the model, but I’ll check it and update the buying list ASAP adding the proper links 😉

Best regards,
Ángel

[Angel LM]

Hmmm… That’s strange

What kind of drivers are you using? A4988? I’m thinking that could be a driver issue. Are they well tuned?

Try to replace the driver of the 5th motor (“X axis”) for the one of the 1st motor (“A axis”) and try again the previous gcodes.

Let’s see if the A motor moves!

[Angel LM]

I missed an important thing, related to GRBL, the $$ parameters should be configured.

Here are my current settings. You can check what these parameters mean in this post of the original GRBL wiki.

Hope it helps!

[Angel LM]

Let’s try it without the test.gcode that I’m not sure that works hahaha

If you send a gcode like this one:

G0 A10 B10 C10 D10 X10 Y10 Z10

All the motors move together? Everyone moves?

The following gcode should move the motors to the initial position

G0 A0 B0 C0 D0 X0 Y0 Z0

[Angel LM]

Hi Burcu!

First of all, welcome to the Thor family officialy!
I really like the purpose of your Thor, it’s the same reason I created and shared it 🙂 Feel free to ask!

I’m looking to the photos attached to your post and I have a pair of suggestions:

1. The power wire is a bit thin, it will limit the amount of current to the board. I would change it for a thicker one.
2. I’m seeing that you short-circuited the switch connector, what can be done, but that thin wire will limit a lot the current given to the board. I would change it for a thicker one (the same thickness as the power wire).

I’m using Ø0.5mm (cooper section) wires if it helps!

About the missing Art2Pulley piece… I don’t know what piece is that one. I’m looking to your printed pieces photo and I’m only missing the Art1GearMotor, Art4 MotorFix, Art4BearingPlug and the Art56Interface.

I’m sure you already know it but you got all the updates STL files at the stl folder at Thor’s github repo

Hope it helps!

Angel LM

[Angel LM]

Hi Burcu,

I don’t get your problem 🙁
Have you connected the motors following this diagram?
Are you using the Universal GCode Sender?
The “Active State” is not “Alarm” (highlighted in red) right?

By the way, I’m not sure that the Test.gcode works, I’ll check it ASAP

Let’s find out the issue 😛

[Angel LM]

Hi Burcu!

I wrote this new page (GRBL & Gcode Control) at Thor’s wiki where is explained how to use the Gcodes to control the Thor motors!
Do not hesitate on asking if you have more questions! 😉

Angel LM

[Angel LM]

Hi Pratik!

If you want to use the same firmware I’m using you have to compile the firmware first. How to do it:

• Compiling GRBL (OSX, Windows and Linux)
  

And then you have to upload the .hex file into your Arduino Mega. How to do it:

• Using OSX
• Using Windows
• Using Linux

That’s it!

If you want to modify the code, first modify it using your favorite text editor then compile it and then upload it to the board 😉

Hope it helps!

Angel LM

[Angel LM]

Hi Roy!

As I already solved the Inverse Kinematics Equation you can start doing the program/script that converts a 3D point (X,Y,Z + the rotation matrix) to the angles of each articulation.

When I was thinking about it, I thought about a python script that reads a 3D point (+ the rotation matrix) from the command line and sends by serial the custom GCode with the solved angles for each articulation.

Hope it helps!

[Author]

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