Brachiograph: A Simple And Cheap Pen-Plotter

The BrachiGraph project consists out of two parts, the hardware design for a servo-driven drawing arm (pen plotter) and software utilities (written in Python) that allow the drawing arm’s servos to be controlled in order to convert a bitmap image into a collection of lines that can be used to draw an image resembling the original, in a variety of styles. All of the software and designs needed to make your own version can be found on the Github page for the project.

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Considering an estimated €14 worth of materials for the project, the produced results are nothing short of amazing, even if the principles behind the project go back to the Ancient Greek , of course. The basic hardware is that of a pantograph, which provides the basic clues for how the servos on the plotter arm are being driven.

The main achievement here is definitely that of minimalism, with three dirt-cheap SG-90 microservos along with some bits of wood, a clothes-peg or equivalent, and of course a pen providing a functional plotter that anyone can assemble on a slow Sunday afternoon from random bits lying around the workshop.

 

Cycloid Drawing Machine Uses Sneaky Stepper Hack

Stepper motors are great for projects that require accurate control of motion. 3D printers, CNC machines and plotters are often built using these useful devices. [InventorArtist] built a stepper-based cycloid drawing machine, and made use of a nifty little hack along the way.

The machine uses a rotating turntable to spin a piece of drawing paper. A pen is then placed in a pantograph mechanism, controlled by another two stepper motors. The build uses the common 28BYJ-48 motor, which are a unipolar, 5-wire design. A common hack is to open these motors up and cut a trace in order to convert them to bipolar operation, netting more torque at the expense of being more complex to drive. [InventorArtist] worked in collaboration with [Doug Commons], who had the idea of instead simply drilling a hole through the case of the motor to cut the trace. This saves opening the motor, and makes the conversion a snap.

[InventorArtist] was able to create a machine capable of beautiful spirograph drawings, and develop a useful hack along the way. Reports are that a jig is in development to make the process foolproof for those keen to mod their own motors. We expect to see parts up on Thingiverse any day now. We’ve also covered the basic version of this hack before.

[Thanks to Darcy Whyte for the tip!]

Watch This LEGO Pantograph Carve Chocolate Messages

[Matthias Wandel] is best known for his deeply interesting woodworking projects, so you might be forgiven for not expecting this lovely chocolate-engraving pantograph made from LEGO. With it, he carves a delightful valentine’s message into a square of chocolate, but doesn’t stop there. He goes the extra mile to cut the chocolate carefully into a heart, and a quick hit with a heat gun takes the rough edges off for a crisp and polished end result.

The cutting end is a small blade stuck inside a LEGO piece, but that’s the only non-LEGO part in the whole assembly. A key to getting a good carve was to cool the chocolate before engraving, and you can see the whole process in the video embedded below.

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Cool Tools: The Pantorouter Turns Tracing On Its Side

Not too long ago we wrote about a small CNC tool for automating certain parts of the woodworking process. At the time it seemed unusual in its intentionally limited scope but a few commenters mentioned it reminded them of another device, [Matthias]’s Pantorouter. It didn’t take much investigation to see that the commenters were right! The MatchSticks device does feel a bit like a CNC version of the Pantorouter, and it seemed like it was more than worth of a post by itself. The Pantorouter is a fascinating example of another small manual-but-automated tool for optimized for accelerating and improving certain woodworking operations.

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Pipes, Tees, And Gears Result In Smooth Video Shots

It’s depressingly easy to make bad videos, but it only takes a little care to turn that around. After ample lighting and decent audio — and not shooting in portrait — perhaps the biggest improvements come from stabilizing the camera while it’s moving. Giving your viewers motion sickness is bad form, after all, and to smooth out those beauty shots, a camera slider can be a big help.

Not all camera sliders are built alike, though, and we must admit to being baffled while first watching [Rulof Maker]’s build of a smooth, synchronized pan and slide camera rig. We just couldn’t figure out how those gears were going to be put to use, but as the video below progresses, it becomes clear that this is an adjustable pantograph rig, and that [Rulof]’s eBay gears are intended to link the two sets of pantograph arms together. The arms are formed from threaded pipe and tee fittings with bearings pressed into them, which is a pretty clever construction technique that seems highly dependent on having the good fortune to find bearings with an interference fit into the threads. But still, [Rulof] makes it work, and with a little epoxy and a fair amount of finagling, he ends up with a complex linkage that yields the desired effects. And bonus points for being able to configure the motion with small adjustments to the camera bracket pivot points.

We saw a similar pantograph slider a few months back. That one was 3D-printed and linked with timing belts, but the principles are the same and the shots from both look great.

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Precision Pantograph Probes PCBs

Electronic components are getting smaller and for most of us, our eyesight is getting worse. When [Kurt] started using a microscope to get a better view of his work, he realized he needed another tool to give his hands the same kind of precision. That tool didn’t exist so he built it.

The PantoProbe is a pantograph mechanism meant to guide a probe for reaching the tiny pads of his SMT components. He reports that he has no longer has any trouble differentiating pins 0.5 mm apart which is the diameter of the graphite sticks in our favorite mechanical pencils.

[Kurt] has already expanded his machine’s capability to include a holder for a high-frequency probe and even pulleys for a pick-and-place variation. There’s no mention of dual-wielding PantoProbes as micro-helping-hands but the versatility we’ve seen suggests that it is only a matter of time.

Four bar linkages are capable of some incredible feats and they’re found all around us. Enjoy one of [Kurt]’s other custom PCBs in his Plexitube Owl Clock, or let him show you to make 3D objects with a laser engraver.

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Tracing A Scene An Old-Fashioned Way

Taking a picture is as simple as tapping a screen. Drawing a memorable scene, even when it’s directly in front of you, is a different skill entirely. So trace it! Well, that’s kind of hard to do without appropriate preparation.

[bobsteaman]’s method is to first whip up a pantograph — it tested well with a felt marker on the end. Next, he built a camera obscura into a small wood box with a matte plexiglass top, which didn’t work quite so well. A magnifying glass above the camera’s pinhole aperture helped, but arduous testing was needed to ensure it was set at perfect position for a clear image. The matte plexiglass was also thrown out and, after some experimentation, replaced with a sheet of semi-transparent baking paper sandwiched between two pieces of clear plexiglass. The result is hard to argue with.

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