Polarsandtisch

Guten Tag

Ich hab mich in einen Sandtisch verliebt.
Zum bauen erschien mir ein Polarsandtisch als das füssigste im Zeichen im Sand.
Ich hab mich gleich ans Zeichen gemacht und habe die Teile aus Plexiglas schneiden lassen.

Die Sandoberfläche hat einen Durchmesser von 70cm.

Ich habe viele übrige Teile von anderen Projekten verwendet zb. die Gt2 Riemenscheiben, die Kugellager und Chromwellen. das 5mm Plexiglas hatte ich auch als Reststück Zuhause.

Hier ein Bild es Projektes:

Bei der Elektronik bin ich ein totaler Anfänger und brauch Hilfe.
Ich habe einen Raspberry 3, einen Arduino Mega miteinen 3D Controller und 2 Neama17 Motoren.

Ich habe ein Problem die X-Y Koordinaten vom G-Code in Winkel umzuwandeln.
Die Übersetzung Motor/Arm hat ein Verhältniss von 1:3
Die Armlänge beträgt 320mm.

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IMG-20200813-WA0009|690x344

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I don’t understand German. But this looks really neat. It looks like a SCARA ZenXY table. There have been two (or more) others like that here. One uses the thetarho output from Sandify with a post prosessor to convert to X Y gcode for Marlin. The other uses Thetarho directly with a raspberry pi as the controller.

Thank you for the flowers.

I live in the Aplen in Italy and speak Italian and German. English wasn’t at my school 40 years ago.

I translate everything with a google translator.

I try very hard to make this table a success for me. Mechanically, it runs 100% as I imagined.

Now I have a problem with the software because I don’t know anything about this subject. I actually wanted to host Sandify on the RPI so that you can access it with your mobile phone. The generated drawings are then sent to an Arduino which then controls the motors. But what I didn’t consider is that the motors need angles and not coordinates.

because my problem is where I can’t get any further at the moment.

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I’m sorry, I don’t speak Italian or German, and my Spanish is pretty bad. So I guess we are stuck with google translate. I will try hard to avoid errors in my English.

I will keep trying as long as you do. I’m sure we can figure it out together.

Here is where we created a conversion from “ThetaRho” from sandify to X, Y for a SCARA machine:

Here is another post, in the same topic. This uses the raspberry pi as the controller, instead of a separate board:

You should be able to run sandify from a pi to create patterns. If you are running it locally, you can also easily make changes for your machine.

There is another program called sandypi. It is brand new, but it should be great for your project. It saves patterns on a raspberry pi and provides a neat interface to choose them.

Hi Klaus,
great start on your scara sand table! Looks awesome :smiley:
I’m on the other side of those Alps you mention :mountain:

@jeffeb3 already pointed you in the right direction. You have 90% of what it would take to use our software on your sandtable. But instead of using the Arduino to control the motors, we directly output the step/direction signals from the RPi. These are sent to a DRV8825 stepper driver. As Jeff already solved the math for translating from the scara setup to theta/rho (in the post he linked above), all you would need is to combine the two :+1:

Hi

First of all, thank you for the help from this forum.
I have received many suggestions and I am still reading (we are still a long way from understanding).

Today the silent blocks which will hold the glass plate later arrived.
I bent the holder and immediately found a small problem.
The arms are too long and hit the silent blocks.
Will draw your arms around to make it fit.

In the meantime I’ve also described the Arduino Mega with Marlin Ramps 1.4 I’ve equipped drivers.
At the moment i want just to get the arms turning.

I will report on.

If you see something that you don’t like,

get in touch.

Servus Klaus

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