When strolling down the beach, there’s always an urge to draw in the sand – it seems compulsory to make your mark by inscribing something. But there’s a dilemma: how do you go about physically drawing it? You could opt to remain standing and attempt to deploy a toe, but that requires a level of dexterity few possess. The only other option is to bend down and physically use your hands. Ultimately, there’s no way to draw anything in the sand without losing your dignity.
The solution? A robot, of course – the brainchild of [Ivan Miranda]. The idea is simple and elegantly executed: make a large linear actuator, place it on wheels, and attach a servo which can position an etching tool to be either in the sand or above it. The whole contraption moves forward one column at a time, making a vertical pass with the marker being engaged or disengaged as required. The columns are quite thin, giving relatively high-resolution text, though this does mean it take a while. Adding another servo and marking two adjacent columns at the same time would be an easy way to instantly double the speed.
The wheels are big and chunky, to ensure the horizontal distance travelled does not change between the top and the bottom. Of course, when making big parts like these it always helps if you’ve already built a giant custom 3D printer. If you want to read more of [Ivan]’s large scale 3D printing antics, checkout his tank with suspension, or plus-sized seven-segment clock.
Continue reading “Drawing Lines In The Sand: Taking Beach Graffiti To The Next Level”










What was their elegant solution for making the fins undulate? Nine lever arms are attached to each fin. Those lever arms are controlled by two crankshafts which extend from the front of the body to the rear, one for each side. A servo motor then turns each crankshaft. Since the crankshafts are independent, that means each fin operates independently. This allows for turning by having one fin move faster than the other. A third motor in the head flexes the body, causing the robot to swim up or down.