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I recapped it, so it's ready to provide another 40 years of awesome music. You can buy it on ebay! Do a search for "Soundcraftsmen PM860"

Yes, 2 layers, one oz copper. See the blog post for a link to the files for the board design: drmrehorst.blogspot.com/2022/05/bank-account-protection-circuit-for.html

The ReDump board is good for a maximum of about 10A. It will not protect the ESC(s), but it will protect the power supply and anything else connected to the power supply from overvoltage generated by the motor(s). If you are using small motors, you might get away with one ReDump, but BLDCs tend to be very high current motors, so you'll probably need one per motor/ESC.

@@MarkRehorst Thank you for your response - the motors I am using is A2212/10T 1400KV. I believe if I stick to a max of 10A then this will give the require protection and I agree I think it is best to do one per motor - especially given the fact that a requirement is that my motors need to change from clockwise to anti clockwise quickly.

Yes, it's corexy. Why would that make it bullshit?

@@MarkRehorst I have a Tronxy 3d Printer and IT cant Print circle 😜🤪 and the system dosent make sense to me... 2motors Fight with each other, need more Power.. overheat etc.

​@@DocOfDead As you can see from the videos, Arrakis works well and has been very reliable. There are many corexy 3d printers out in the world that work fine, including mine. The motors don't "fight" each other. They work in tandem. Maybe you need to tune up your printer a bit, especially motor current. If the motors are hot, turn down the current.

@@MarkRehorst UFC Fight core ist a better Name for this Bullshit.. sorry.. but yours Look good 🧐

Voron 4 Motors Just for leveling 💪😆 how fast do you Print in Z Axis??? 💩🥵

Thanks! I have a few more designs for different types of mounts for them, too, at the blog.

Not steppers, servomotors with integrated drivers. I send them step/dir/enable from the controller board. If I used larger drive pulleys the mechanism could run much faster.

Sandify can generate a few fractal patterns but I think they are all L system type. There's no provision for things like Julia sets or Mandelbrot sets.

Don't be jealous, start on a project! It doesn't matter what it is, just follow it down the rabbit hole

The edge speed is 1000 mm/sec. It can easily go faster, but it starts to get a little noisy if I push it any faster. The table is capable of such speed because it uses servomotors instead of stepper motors.

Check my blog on it at drmrehorst.blogspot.com/2021/10/arrakis-this-is-part-of-weirding-way.html?m=1

@@MarkRehorst have been reading the many pages. Thanks very much for all the details!

Thanks, I'll add ASMR to the tags!

Yes, not steppers. I started with steppers and couldn't get them to go fast enough, and the faster they went, the noisier they were. The servo motors are much faster and quieter.

@@MarkRehorst I see, very good, Keep up the good work Mark.

@@MarkRehorst How do you define "fast enough"? 200mm/s seems waaaay overkill for a sand table

@@Synthetica9 look at the videos and tell me if 200mm/sec is really fast enough, especially on a pattern that has a lot of edge motion.

@@MarkRehorst I suppose it depends on what you're after. If you want to quickly lay down a pattern, maybe 200 isn't enough, but if you just want something that gradually changes over time it's more than enough. I am currently planning out a build, and I don't intend to run it faster than 50mm/s

No, but I might if your pockets are deep enough!

I wrote a blog post on the build with a link to the CAD file that has all the details you would need to build something like it. See: drmrehorst.blogspot.com/2021/10/arrakis-this-is-part-of-weirding-way.html

Nope. That's not what this does.

Arrakis uses Reprap firmware running on a Duet 2 WiFi 3D printer controller board. The motors are IHSV integrated servomotors with their own drivers that take step/direction/enable signals from the controller. I first used these motors in Arrakis' predecessor, The Spice Must Flow and there are blog posts on both machines here: drmrehorst.blogspot.com/2020/04/the-spice-must-flow-gets-servo-motors.html and here: drmrehorst.blogspot.com/2021/10/arrakis-this-is-part-of-weirding-way.html The motors are capable of much greater speed and acceleration than I am using. Right now the speed is limited to about 1600 mm/sec and acceleration to 2g by the 20 tooth drive pulleys I used, but larger pulleys would enable much higher speeds and accelerations. Of course, if you go much faster, the machine will throw not only the sand but also the ball.

Thanks! I'm working on a blog post about it, but there won't be a step by step or BOM. One of the other videos shows the mechanism pretty clearly, and I'll post a link to a CAD file. Anyone who can build a sand table should be able to fill in details. The key to high speed is to use servo motors, not steppers. A good controller helps too. I used a Duet wifi controller so I don't have to have a control panel on the table and all the electronics can be hidden. The servo motors need bigger power supplies than steppers.

Blog post is up. See: drmrehorst.blogspot.com/2021/10/arrakis-this-is-part-of-weirding-way.html

I'll try to shoot a video tonight and get it posted tomorrow.

No problem at all, I'd just have to use less sand. This table can draw patterns up to almost 2000 mm/sec, so drawing time is never an issue.

Why do you need all that? There's plenty of info in the videos to get you started! I'll be posting a blog on this table in a few days and I'll post a link here. There won't be a BOM- you're going to have to figure that out for yourself. I'll be happy to answer specific questions...

The configuration is super easy- there's no heater, fan, extruder, or Z axis, so all you do is set up the endstops, travel limits, and motor directions. I think there's more to setting up the wifi than there is to setting up the rest of the mechanism.

@@MarkRehorst Will look out for the blog post. There are a few ... popular open source hobby engineering projects right now that provide CAD, BOM, firmware, etc., is where I got the idea, naturally. One such project is sitting on my desk right now, Voron-ing away at some redundant, useless tchotchkes probably. Your sand table (potentially pitched to my wife as a "new interesting coffee table") might actually stand a chance of making it into our tv area.

@@samtny1 Successfully designing and building a complex project yourself is mostly a matter of taking it one step at a time, always working toward the final goal. Take some hardware you have or know where to get, some stuff you know and some stuff you have to learn, and put it together. When you get stuck, and you will, think of one small thing you can do to move forward and do it. Then do that again and again, and pretty soon, the whole thing is done. This project is a lot like building a 3D printer. The controller is a Duet 3D printer controller (many other can be made to work, too) that comes loaded with firmware. Power supplies and LED strips are off-the-shelf and available at many places. Patterns are generated using Sandify (do a search). There's no programming required to get it all working, unless you want to. It's a lot more fun and educational to design and build it yourself, and you end up with exactly what you want. You know how it works and how to fix it if it breaks, and what sort of modifications you can make later.

@@samtny1 Blog post with CAD file link is here: drmrehorst.blogspot.com/2021/10/arrakis-this-is-part-of-weirding-way.html

Yeah, the motors are super quiet. Most of the noise comes from the X axis sliding along the Y axis rails and the gear teeth hitting the belt teeth on the motor pulleys. There's a sheet of EPDM rubber glued to the bottom of the table so the ball rolling in the sand is quiet.

The fur matches the LED lighting inside the table.

Thanks! Both axes use PTFE bearings. For the Y axis, the whole X axis slides on two PTFE blocks, one of which is spring loaded, that fit the 10 mm slot in the t-slot frame. The magnet carriage which moves in X, has 4 small rectangular PTFE blocks that contact the square aluminum tube that is the X axis guide. Even though PTFE is used, the mechanism has pretty high friction. The servomotors have more than enough torque to keep it all moving, even at high speeds and accelerations. The mechanism is very quiet.

@@MarkRehorst Nice idea for the ptfe, I was looking into linear rails as an alternative solution ;)

No plans right now, but things may change...

Check the new Arrakis sand table mechanism in some of my other videos. More to come as I finish the sand box for it...

The motors mount on the frame rails that serve as the Y axis guide rails. That meant that I had to put the corner pulleys on separate axles in order to keep some of the belt segments parallel to the Y axis rails. I could have stacked the pulleys on the corner pulley blocks, but that would probably have reduced the drawable width of the table (the X axis) and would have complicated the Y axis bearing/pulley block design. My 3D printer has the pulleys stacked on both the Y axis bearing/pulley blocks and the corner pulley blocks. I was able to do that because the motors don't mount on the frame rails and I didn't use the frame rails for guidance.

@@MarkRehorst yes the UMMX, the best build I have ever seen. Btw, dont you think that this setup can be de purpose for a 3d printer (bieden style) ? As in the 3d printer need not face forces like CNC router so a light weight hot end may do the job??

​@@PS-nf3xw In the sand table the bearings are all pretty loose so precision and accuracy would probably be unacceptably low for 3D printing. Sand is a low resolution medium so poor precision and accuracy are acceptable in the sand table. Then there's the motors. I tried using the servomotors from the sand table in my 3D printer, UMMD, and found accuracy problems. It may be that I need to adjust some of the motor driver parameters, but I haven't been able to find any good information on doing that.

No, that's H-bot. I used a corexy mechanism. See: corexy.org/

How deep are your pockets?

I am in the process of building the sandbox now. As soon as that is done there will be more videos and a blog post with details including a link to the master CAD file.

It uses a Duet 2 wifi 3d printer controller board. Pattern files are simple gcode generated by Sandify. The mechanism is a corexy type, similar to that used in 3d printers. You can find more details on my blog. Search for "blogspot rehorst".

Do a search for "blogspot rehorst"...

here: drmrehorst.blogspot.com/

Thanks Pete!