How To Make Laser-cut Decals On The Cheap

March 12, 2022 by Donald Papp 13 Comments

Want to make a sweet adhesive decal with a complex design and floating elements, but all you have is a laser cutter and some tape? Good news, because that’s all you need with this method of creating adhesive tape decals on a laser cutter demonstrated by the folks at [Lasers Over Los Angeles]. The overall technique is very similar to creating vinyl decals and using tape transfer to apply them, but is geared towards laser cutters and nice, cheap tape.

This method also makes applying to non-flat surfaces a breeze.

The way it works is this: paper-based tape (such as blue painter’s tape) is laid down in strips on the laser cutter’s honeycomb bed, forming a nice big rectangle big enough for the intended design. Then, the laser cutter cuts vector art into the tape, resulting in an adhesive decal ready to be stuck to some other surface. Transferring is done by using good quality clear packing tape to “pick up” the decal, then move it to where it needs to be.

To do this, one lays strips of packing tape onto the top of the design on the laser bed, then lifts the design up and away. Move the design to its destination (the clear packing tape helps in eyeballing the final position), press the decal onto the final surface, and carefully peel away the clear packing tape. This works because the packing tape sticks only weakly to the back of the painter’s tape; it’s a strong enough bond to hold the decal, but weak enough that the decal will stick to a surface even better.

It’s true that painter’s tape isn’t as durable as vinyl and the color selection is a bit limited, but design-wise one can go as big as the laser bed allows, and the price is certainly right. Plus it’s easily cut by even the most anemic of diode lasers.

Speaking of desktop vinyl cutters, they may have small working areas compared to most laser cutters, but they have some fantastic workshop applications. They can even do home PCB fabrication, by way of knocking out three essential pieces: the etching mask, solder mask, and solder stencil.

A Soft Thumb-Sized Vision-Based Touch Sensor

March 12, 2022 by Dave Rowntree 10 Comments

A team from the Max Planck Institute for Intelligent Systems in Germany have developed a novel thumb-shaped touch sensor capable of resolving the force of a contact, as well as its direction, over the whole surface of the structure. Intended for dexterous manipulation systems, the system is constructed from easily sourced components, so should scale up to a larger assemblies without breaking the bank. The first step is to place a soft and compliant outer skin over a rigid metallic skeleton, which is then illuminated internally using structured light techniques. From there, machine learning can be used to estimate the shear and normal force components of the contact with the skin, over the entire surface, by observing how the internal envelope distorts the structured illumination.

The novelty here is the way they combine both photometric stereo processing with other structured light techniques, using only a single camera. The camera image is fed straight into a pre-trained machine learning system (details on this part of the system are unfortunately a bit scarce) which directly outputs an estimate of the contact shape and force distribution, with spatial accuracy reported good to less than 1 mm and force resolution down to 30 millinewtons. By directly estimating normal and shear force components the direction of the contact could be resolved to 5 degrees. The system is so sensitive that it can reportedly detect its own posture by observing the deformation of the skin due its own weight alone!

We’ve not covered all that many optical sensing projects, but here’s one using a linear CIS sensor to turn any TV into a touch screen. And whilst we’re talking about using cameras as sensors, here’s a neat way to use optical fibers to read multiple light-gates with a single camera and OpenCV.

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Rugged Cyberdeck Makes The Case For Keeping Things Water-Tight

March 12, 2022 by Kristina Panos 16 Comments

Many people build cyberdecks just for the heck of it, and there’s nothing wrong with that at all. On the other hand, [cyzoonic]’s rugged ‘deck is a bit more purpose-built. In this instance, the purpose is software-defined radio.

Underneath those sweet custom-cut panels lies a Raspberry Pi 3B and a BOM full of parts that can be had on Ali Express. There’s also an ESP32 that takes input from the keypad plus the 5 buttons that control the display, and the two potentiometers. [cyzoonic] can dial in frequencies with the knobs, or by punching in digits on the keypad.

One of the problems with using a Pelican case is this — how do you install any type of panel without compromising the case’s water-tightness? [cyzoonic] mentions in the comments that Pelican makes a bracket that allows for panels and things to be screwed down without breaching the case. But in this case, [cyzoonic] made their own brackets in a similar fashion.

Another problem with Pelican cases (and cyberdecks in general that are built into hinged boxen) is something that doesn’t get enough attention: typing ergonomics. Personally, we take comfortable and ergonomic typing fairly seriously, and would love to see a cyberdeck that speaks to this issue.

In the meantime, we’ll have to take [cyzoonic]’s word that while it’s not terribly comfortable to type with the ‘deck on a tabletop, sitting on the floor hunched over the thing like a true hacker is much better. This is a work in progress (at least the IO project anyway), so we’ll be tuning back in occasionally to see if any more instructions appear.

Speaking of ergonomic cyberdecks, here’s the one that drew the line in the sand for us — [Tinfoil_Haberdashery]’s lovely ErgoDox-based NUC machine.

Make It Compatible

March 12, 2022 by Elliot Williams 25 Comments

I’m probably as guilty as anyone of reinventing the wheel for a subpart of a project. Heck, sometimes I just feel like working on a wheel design. But if that’s the path you choose, you have to think about whether or not it’s important that others can replicate your project. The nice thing about a bog-standard wheel is that everyone has got one.

The case study I have in mind is a wall-plotter project that appeared on Hackaday this week. It’s a really sweet design, and in many ways would be an ideal starter project. I actually need a wall plotter (for reasons) and like a number of the choices made. For instance, having nearly everything, including the lightweight geared steppers on the gondola makes it easy to install and uninstall — you just pin up the timing belt from which it hangs and you’re done. Extra weight on the gondola helps with stability anyway. It’s open source and based on the Arduino libraries, so it should be easy enough to port to whatever microcontroller I have on hand.

But the image-generation toolchain is awkward, involving cutting and pasting into a spreadsheet, which generates a text file in a custom plotting micro-language. Presumably the designer doesn’t know about Gcode, which is essentially the lingua franca of moving machines, or just didn’t feel like implementing it. Where in Gcode, movement commands are like “G1 X100 Y50”, this device expects “draw_line(0,0,100,50)”. They’re essentially equivalent, but incompatible.

I totally understand that the author must have had a good time thinking up the movement commands and writing the spreadsheet that translates SVG files into them. I’ve been there and done that! But if the wall plotter spoke Gcode instead of its own dialect, it would slot instantly into any number of graphics processing workflows, which would make me, the potential user, happier.

When you are looking at reinventing the wheel, think about your audience. If you’re the only person likely to see the project, go ahead and scratch whatever itch you’ve got. You’ll learn more that way. But if you want to share the project with as many people as possible, adhering to the most widely used standards is a good choice for your users, even if it is less fun than dreaming up your own movement language.

Modular Pockit Computer Is More Than Meets The Eye

March 12, 2022 by Ryan Flowers 38 Comments

“Modular” and “Computer” have historically been on the opposite ends of a rather awkward spectrum. One could argue that a hobbyist grade PC is modular, but only to a point. Re-configuring it on the fly is not readily possible. Modular laptops are slowly happening, but what about handheld devices, where our needs might change on a regular basis?

Enter the Pockit: a fully modular IoT/edge computing device that can be reconfigured on the fly without having to reprogram it. Don’t browse away from this page without watching the demonstration video below the break. It just might be the “mother of all demos” for the current decade.

A modular base provides basic computing power in the form of a Raspberry Pi, like many other projects. The base has twelve magnetic connectors, each with twenty I/O and power pins. When a module is added, the operating system detects the new module and loads an appropriate program on the fly. When more modules are loaded, it automatically configures itself so that all modules have a purpose. This allows the Pockit to be an integrated IoT device, an edge computing powerhouse, a desktop computer, a Blackberry-esque handheld, or a touch screen tablet, and so many more things.

For example, if a camera is added, it displays an image on a screen — if there’s a screen. If a button is added, it automatically takes a picture when the button is pressed. If you want the camera to be motion activated, just add a motion sensor. Done. External devices can be controlled with relays and home automation integrates almost seamlessly.

There are a great number of features that we’re glossing over for the sake of getting to the point: Go watch the video and when you’re done, perhaps you’ll be as astonished as we are. We’ve expressed our love of modular hardware like the Pockit in the past, and after watching this demo, we can only hope that this is what the future of computing and electronics looks like!

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Build Yourself A Weather-Reporting Diorama

March 12, 2022 by Lewin Day 1 Comment

These days, if you don’t fancy watching morning TV, you can always get an update on the day’s weather from your smartphone, computer, or any one of a series of other connected devices. However, if you’re looking for a more fun way to see what’s in store, this weather diorama from [Lewis] of DIY Machines might be just what you’re looking for.

The build uses an ESP32 as the brains of the project, responsible for querying the Internet for up-to-date weather information. This info is then displayed on a 2.9″ e-ink display, showing the temperature, chance of rain, and wind speed predicted for the local area. So far, so straightforward.

However, where it gets really creative is the use of laser-cut “scene discs” with different graphics on them to represent different weather conditions. They can alternatively be 3D printed,too. These are rotated via servos controlled by the ESP32, allowing the diorama to display a representative scene informed by the current forecast. If there’s snow coming, you’ll see a snow man, but if things are looking fine, you’re more likely to see a woman strolling with a dog.

It’s a fun way to learn about what Mother Nature has in store, and would look great on any breakfast bar to boot. We’ve seen some great builds from [Lewis] before, too, like this amazing seven-segment clock shelf.

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Building A Lego Paper Shredder

March 11, 2022 by Lewin Day 3 Comments

Sometimes we need to destroy documents before throwing them away for security reasons, and shredders are a primary way of achieving that. If you don’t have your own, you might consider building your own, like [Brick Experiment Channel] did using Lego.

First attempts at shredding a small slip of paper with interlocking gears were a failure, merely crumpling the paper in an attractive rippled manner. As the “Top Secret” piece of paper says, “If you can read this, the shredder didn’t work.” Adding more gears managed to gouge a couple holes in the paper, but it was still far from effective. Continuing down this path further only stalled the Lego motor.

A redesign with different sized gears did eventually manage to tear the paper into large chunks. One set of gears would hold on to the paper while a following set would tear away a section. A further modification combined this method with using bevel gears as a sort of blade, and improved shredding performance further, to the point where the paper was torn into satisfyingly tiny fragments.

It’s a fun little build, even if it won’t come close to taking on a full page of A4. It’s a great example of what can be achieved when you set a simple goal with readily measurable outcomes, in this case, the legibility of the original message on the paper.

We’ve seen a few shredders around here before too. Video after the break.
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