Sand Drawing Plotter Runs On ESP32

July 21, 2023 by Lewin Day 3 Comments

Humans have always drawn lines in the sand, whether it’s to communicate a plan of attack or to indicate metaphorically a very real boundary. It’s also something we do just for the aesthetic pleasure, and this plotter from [aidenvigue] is great at performing in just that role.

The plotter traces patterns in the circular sand tray by dragging a small marble with a magnet. This is achieved with a pair of NEMA 17 stepper motors, set up in a polar coordinate fashion. One stepper motor controls the angle, while another motor controls the marble’s distance from the center point of the circle. It’s a simple way to build a circular plotter, and works far better than a Cartesian setup would for this geometry. The build uses an ESP32 as the brains of the operation. It hosts a web interface that allows various patterns to be selected and run on the device. It also runs a set of addressable SK6812 LEDs that light the sand rather nicely.

We’ve seen some great sand plotters before, and have always been particular fans of the larger variety. Video after the break.

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Zen Rock Garden Table Uses Magnets And Sand

April 26, 2012 by Brian Benchoff 14 Comments

[Nick] is working on a prototype of a coffee table sand plotter that draws patterns in sand a lot like a zen rock garden.

[Nick]’s zen rock garden uses a magnet to draw a ball bearing across the sand in interesting patterns. The build uses 3D printed gears and laser cut parts to rotate the table around and move the magnet along a radius of the circle. During the first test of the prototype, the ball bearing jerked around but this problem was solved by adding a piece of foam under the sand. Power is supplied through a slip ring in the base, and the table is controlled through Bluetooth.

Speaking of magnet-and-ball-bearing zen coffee tables, we ran across this video of a more professional-looking prototype that was the basis for a successful Kickstarter campaign. Like [Nick]’s prototype, the entire build relies on magnets and a ball bearing to move sand around in patterns. Because this zen table uses an XY axis instead of [Nick]’s polar setup, drawing logos is a lot easier math-wise, lthough it doesn’t look quite as cool as a circular rock garden.

After the break you can see these zen rock garden coffee tables in action.

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Plotting Pictures With Light

February 11, 2012 by Brian Benchoff 1 Comment

Flashing LEDs for a persistence of vision display are on bicycle wheels, alarm clocks, and even light painting sticks to draw images in the air. What if you wanted to plot an image in the air (translation) with a single LED? That’s what [acorv] did after taking a cue from a polar plotter.

Like the polar plotter and Drawbot, [acorv]’s build began with a pair of stepper motors and fishing line (translation). [acorv]’s brother upped the stakes a bit and suggested replacing the marker with an LED and taking long exposure photographs. Armed with a DSLR and a lot of patience, a few experimental pics were taken. To plot the image, the Lightbot flashes its LED as it goes across the plot area. The process of building an image pixel by pixel takes a while – eight minutes for this image – but the brothers were encouraged enough to take their rig outside.

After setting up the polar plotter between two tripods, [acorv] and his brother made this image in the dead of night. It’s an interesting spin on the POV LED builds we’ve seen before. Check out [acorv]’s Lightbot slowly drawing something after the break.

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Polar Pen Plotter Draws Huge Images Very Slowly

November 17, 2011 by Brian Benchoff 7 Comments

[Euphy] just posted an Instructable of his Polargraph drawing machine that’s able to draw huge images slower than molasses in November. The plotter only uses two stepper motors to control the position of the pen and can be made nearly entirely from salvaged parts – [Euphy] built his for just about £150.

The Polargraph uses two stepper motor on the top corners of a large, flat surface. A weighted pen carriage is attached to both motors with beaded cord that’s often seen in window blinds. By controlling the distance from the carriage to each motor, the position of the pen can be precisely controlled. It’s not a very fast way of drawing an image (check out the real-time video), but it sure is interesting to watch.

There have been a few other rope-and-chain plotters, like Der Kritzler and Hektor. [Euphy]’s work is the is one of the best documented builds we’ve seen, and he’s also put up the code and a website.

We really could have used [Euphy]’s plotter when we wanted to draw some whiteboard art. While we’re out dumpster diving for some small stepper motors, check out the time-lapse video of the Polargraph after the break.

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