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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Clock Testing Sans Oscilloscope?

March 11, 2022 by Al Williams 17 Comments

Like many people who repair stuff, [Learn Electronics Repair] has an oscilloscope. But after using it to test a motherboard crystal oscillator, he started thinking about how people who don’t own a scope might do the same kind of test. He picked up a frequency counter/crystal tester kit that was quite inexpensive — under $10. He built it, and then tried it to see how well it would work in-circuit.

The kit has an unusual use of 7-segment displays to sort-of display words for menus. There is a socket to plug in a crystal for testing, but that won’t work for the intended application. He made a small extender to simplify connecting crystals even if they are surface mount. He eventually added a BNC socket to the counter input, but at first just wired some test leads directly in.

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Making A Locket From A Coin

March 11, 2022 by Lewin Day 9 Comments

Some countries have strict laws around the destruction or alteration of issued currency, but then again, some countries don’t. Citizens of those in the latter category may enjoy undertaking a build similar to this locket created by [Elier Olivos], crafted from a large coin.

A compass is first used to mark out a line on the coin’s perimeter, before it is cut in half with a fret saw. Once the two halves of the coin are smoothed out, it’s then time to heat them and quench them so they’re more malleable for pounding into a slightly domed shape. Metal rings are then fabricated and added to each half to give the locket some depth.

A hinge is then carefully made and fixed into the edges of the coin halves, giving the closed coin an almost seamless outside appearance. A small latch installed on the inside helps hold the locket closed. The final touches are to attach a loop for affixing the locket to a chain for the wearer, and to polish the inside of the locket up to a mirror shine.

[Elier] makes the build look easy through a combination of his amazing skills with his hands and the help of a some esoteric tooling. It can be very relaxing to take in a video of a master at work, and we’ve seen some great examples recently. Video after the break.

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You Can Build Your Own Sushi Train

March 11, 2022 by Lewin Day 19 Comments

According to [Garage Avenger], in Norwegian culture it’s considered impolite to ask for things to be passed across a dinner table, so much standing and reaching is the course of the day. To assist in reducing the effort required, he set about building his own sushi train device to solve the problem, giving equal condiment access to all!

The system is capable of taking plenty of weight from heavy dinner bowls, altogether quite different than relatively-light sushi dishes on plastic plates.

The system is actually relatively simple, relying on a Wemos D1 Mini controlled by a Blynk app to run the show. Mechanically, a large drive gears is turned by a stepper motor to drive the wooden conveyor chain that actually makes up the “sushi train.” The chain links ride on a bed of Norwegian one krone coins acting as rollers.

The result is a working table-sized sushi train that really does carry plates around well. It didn’t stop people leaning over [Garage Avenger] at the dinner table, but it makes a great centerpiece on the dinner table for sharing dishes like tacos.

We’ve seen similar table technology, the Lazy Susan, around these parts before. Video after the break.
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