These Illusions Celebrate Exploiting Human Senses

June 16, 2023 by 7 Comments

Illusions are perceptual experiences that do not match physical reality, and the 2023 Illusion of the Year contest produced a variety of nifty ones that are worth checking out. A video for each is embedded below the break, but we’ll briefly explain each as well.

Some of the visual illusions play with perspective. One such example happens to be the contest winner: Platform 9 3/4 has a LEGO car appear to drive directly through a wall. It happens so quickly it’s difficult to say what happened at all!

Another good one is the Tower of Cubes, which appears as two stacks of normal-looking hollow cubes, but some of the cubes are in fact truly bizarre shapes when seen from the side. This is a bit reminiscent of the ambiguous cylinder illusion by Japanese mathematician and artist [Kokichi Sugihara].

Cornelia is representative of the hollow face illusion, in which a concave face is perceived as a normal convex one. (Interestingly this illusion is used to help diagnose schizophrenia, as sufferers overwhelmingly fail to perceive the illusion.)

The Accelerando Illusion is similar to (but differs from) an auditory effect known as the Risset Rhythm by composer Jean-Claude Risset. It exploits ambiguities in sound to create a dense musical arrangement that sounds as though it is constantly increasing in tempo.

The Buddha’s Ear Illusion creates the illusion of feeling as though one’s earlobe is being stretched out to an absurd length, and brings to mind the broader concept of body transfer illusion.

While it didn’t appear into the contest, we just can’t resist bringing up the Thermal Grill Illusion, in which one perceives a painful burning sensation from touching a set of alternating hot and cold elements. Even though the temperatures of the individual elements are actually quite mild, the temperature differential plays strange tricks on perception.

A video of each of the contest’s entries is embedded below, and they all explain exactly what’s going on for each one, so take a few minutes and give them a watch. Do you have a favorite illusion of your own? Share it in the comments!

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A Modular Analogue Computer

June 12, 2023 by 20 Comments

We are all used to modular construction in the analogue synth world, to the extent that there’s an accepted standard for it in EuroRack. But the same techniques are just as useful wherever else analogue circuits need to be configured on the fly, such as in an analogue computer. It’s something [Rainer Glaschick] has pursued, with his Flexible Analog Computer, an analogue computer made from a set of modules mounted on breadboard strips.

Standard modules are an adder and an integrator, with the adder also having inverter, comparator, and precision rectifier functions. The various functions can be easily configured by means of jumpers, and there are digital switches on board to enable or disable outputs and inputs. he’s set up a moon landing example to demonstrate the machine in practice.

We’re not going to pretend to be analogue computer experts here at Hackaday,but we naturally welcome any foray into analogue circuitry lest it become a lost art. If you’d like to experiment with analogue computing there are other projects out there to whet your appetite, and of course they don’t even need to be electronic.

Hackaday Prize 2023: Low Cost Braille Embosser From 3D Printer Parts

May 31, 2023 by 8 Comments

The limited availability of texts transcribed to Braille and the required embossing equipment is a challenge world wide, but especially in poorer countries. To alleviate this problem, a team makers from in Cameroon have been developing BrailleRAP, an open source Braille embosser.

BrailleRAP is built built using commonly available 3D printer components, printed parts, and a laser-cut acrylic or wood frame. Paper is fed between a pair of carriages, the bottom one punching dots with a solenoid while the other acts as the anvil. Sheets of paper are fed in one or two at a time with stepper controlled rollers to control the position. At a cost of about $250, it is about a tenth of the price of the cheapest commercial solution, and the team have created excellent documentation so anyone can build it.

BrailleRAP was inspired by BRAIGO, another Hackaday-featured embosser assembled LEGO Mindstorm parts. We also featured another simple, but ingenious handheld embosser for portable use.

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Learning 3D Printing Best Practices From A Pro

May 26, 2023 by 13 Comments

It might seem like 3D printing is a thoroughly modern technology, but the fact is, it’s been used in the industry for decades. The only thing that’s really new is that the printers have become cheap and small enough for folks like us to buy one and plop it on our workbench. So why not take advantage of all that knowledge accumulated by those who’ve been working in the 3D printing field, more accurately referred to as additive manufacturing, since before MakerBot stopped making wooden printers?

That’s why we asked Eric Utley, an applications engineer with Protolabs, to stop by the Hack Chat this week. With over 15 years of experience in additive manufacturing, it’s fair to say he’s seen the technology go through some pretty big changes. Hes worked on everything from the classic stereolithography (SLA) to the newer Multi Jet Fusion (MJF) printers, with a recent focus on printing in metals such as Inconel and aluminum. Compared to the sort of 3D printers he’s worked with, we’re basically playing with hot, semi-melted, LEGOs — but that doesn’t mean some of the lessons he’s learned can’t be applied at the hobbyist level. Continue reading “Learning 3D Printing Best Practices From A Pro” →

An Elegant Solution For Smart Home Device Integration

May 20, 2023 by 49 Comments

Integrating non-smart devices into your home automation system can be a cumbersome process, involving the wiring of multiple modules. However, [Pricelesstoolkit] has created the ESPClicker — a compact, ESP8266-based module that can remotely “press buttons” and simplify this process.

The ESPClicker’s core feature is its three relays that can be soldered to the button terminals of any existing “dumb” device, as [Pricelesstoolkit] demonstrated with his coffee machine in the video after the break. One of the relays can also be configured in the normally closed configuration. A compact twelve pin connector provides a removable wiring interface for the buttons, additional relays, power and even a contactless power detector that can be wrapped around an AC wire.

[PricelessToolkit] has done several Home Assistant related projects, and we recently featured his little Home Assistant controlled guardian bot. We’ve also seen other project that make use of ESPHome, like a iPod style scroll wheel and a LEGO train set.

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Big Tactile Button Is Silly But Cool

May 18, 2023 by 8 Comments

Every hacker is familiar with those teeny little tactile buttons that are so enjoyable to click over and over again. [ROBO HUB] has built a giant version as a tribute, and it works just like the real thing!

The giant button has been scaled up 20 times compared to the original. For simplicity’s sake, [ROBO HUB] designed this replica to use materials readily available around the home. Thanks to its cardboard construction, it’s easy to replicate with a minimum of tools. One need merely cut out the various sections before assembling them together with hot glue, with popsicle sticks serving as the legs. A juice bottle is used as the primary button itself, with aluminium foil serving as the contacts and rubber bands standing in for the spring.

It’s not the most useful button, given that it it’s quite fragile and has a weak spring return. However, it would be a great teaching tool to show students exactly what’s going on inside an actual button. As a bonus, it looks like it would be remarkably fun to pound on to activate some kind of massive air horn. Just an idea.

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Wood game piece being carved by a CNC mill with a hacked rotary axis

This $12 CNC Rotary Axis Will Make Your Head Spin

May 15, 2023 by 19 Comments

[legolor] brings us a great, cheap rotary axis to add to your small 3 axis CNC mills. How are you going to generate G-Code for this 4th axis? That’s the great part, and the hack, that [legolor] really just swapped the Y axis for the rotation. To finish the workflow and keep things cheap accessible to all there’s a great trick to “unwrap” your 3D model so your CAM software of choice thinks it’s still using a linear Y axis and keeps your existing workflow largely intact. While this requires an extra step in Blender to do the unwrapping, we love the way this hack changes as little of the rest of your process as possible. The Blender script might be useful for many other purposes too.

Wood game pieces carved from wood by a CNC mill with a hacked rotary axis

The results speak for themselves too! We thought the 3D printed parts were suspect in a CNC setup, but for the small scale of game pieces and milling wood, the setup is stable enough to produce a surprisingly accurate and detailed finish. If you want to try the same approach with something larger or a tougher material, [legolor] has a suggestion of a tailstock setup that’s still under $100 USD. Continue reading “This $12 CNC Rotary Axis Will Make Your Head Spin” →