[Ivan] seems to enjoy making 3D printed vehicles with tracks. His latest one uses 50 servo motors to draw patterns in the sand at the beach. You can see it work in the video below. Well, more accurately you can see it not work and then work as the first iteration didn’t go exactly as planned.
An Arduino Mega 2560 provides the brains and the whole unit weighs in at almost 31 pounds, including the batteries. We didn’t see Ivan’s design files, although it wouldn’t be hard to do your own take on the robot.
Speaking of the weight, we were amused at [Ivan’s] quick and dirty trailer he built to haul the thing around. We wondered if he had those wheels sitting around or if he had to source them from somewhere for this project.
The robot more or less moves in a straight line and the servos either drag a pointy part into the sand or lift the pointy part up so the sand is undisturbed in that area. The robot isn’t perfect. Not only did it not work the first time, but it also looked like it dropped at least one pointy part during the second test run. The tracks seemed to provide good traction, but we would not want to bet that the motion was completely straight.
On the other hand, it did get the job done. It was a lot of wiring and we suspect that’s why it was made all in one piece. Making it break down into sections would have been nice for transport. You might even be able to make it take a varying number of sections if you did it right. However, it would take a lot of connectors and a way for those connectors to support the weight of the beam, so that would be a much tougher problem.
We wish the design files were posted, but we still thought this was a neat enough idea and easy enough to figure out. We aren’t likely to build a 30-pound robot, but we might think about replicating it on a smaller scale to take to our local beach next summer.
We couldn’t help but remember Skryf, the robot that didn’t draw in the sand but drew with sand. Then there’s also SandBot.
Love Donostia !!!
as proud as I am of anyone who wants to drill that many holes in a piece of steel, I think extruded rail might be the better solution here. Plus I would use solenoids with plungers rather than servos, but then again he’s on a beach right now playing and I’m in an office typing :-)
Just looked like cheapass servos too, could have used a scrap bed rail and globbed them all on with epoxy.
solenoids have nonlinear force, are only binary, more expensive, need power (electronics).
extrusion is harder to source, and while you save time on drilling and tapping, you’ll probably spend it fiddling with the extrusion nuts. idk how it compares structurally.
He’s got a 3D printer, printing little twist-mounts or snap mounts to mount a part to extruded rail is simple. True that solenoids require a FET, but servos require PWM which is a bit more complicated.
Generally you can find solenoids surplus so can get a lot for cheap.
I thought about this more, and if he had stepper motors as the drive motors he could step a specified distance, punch a line with the solenoids, move a specified distance and do it again, I bet you could get decent resolution – even image quality.
Hmm, wonder how many solenoids I have in the parts box . . . damn, they are all AC.
Skryf was the one that inspired this https://hackaday.com/2017/09/03/poetry-in-motion-with-a-sand-dispensing-dot-matrix-printer/