Useful Build Tips For Making LED Panel Frames

February 23, 2021 by Donald Papp 9 Comments

[NotLikeALeafOnTheWind] has created many LED-based display projects, and shares his method for making attractive LED panel frames and mounts. At first glance it may look as though slapping a rectangle of aluminum extrusion around a display is all it takes, there is also the mounting and management of wiring, power supply, and possibly a Raspberry Pi to deal with. The process of building an attractive frame also has a few hidden gotchas that can be avoided with a bit of careful planning.

Magnetic feet on the LED panels makes mounting much easier and more flexible.

Here is one tip that will resonate with some readers: don’t rely on specified dimensions of parts; measure the actual parts yourself. There can be small differences between what a data sheet says to expect, and the dimensions of the actual part in one’s hands. It may not be much, but it can be the difference between an ideal fit, and something that looks like a bit of a hack job.

[NotLikeALeafOnTheWind] provides some basic frame layouts, and suggests using two- or three-channel extrusions to provide a flat bezel around the display edge if desired. Mounting the LED panel itself is done with magnetic feet and providing a length of steel bar to which the display can attach. This can provide a flush mount while avoiding the whole issue of screw-mounting the display panels themselves, or sliding them into channels. For mounting all the other hardware, a piece of DIN rail and some 3D-printed parts takes care of that.

The result looks slick and sturdy, and some of the tips are sure to be useful even if the whole process isn’t applied. We like the way the basic design scales and is flexible about the thickness and size of the LED panels themselves, making it a promising way to accommodate perfectly functional oddball panels that end up in the trash.

DIY Bread Slice Paper Goes Against The Grain

February 17, 2021 by Kristina Panos 14 Comments

It’s the dead of winter here in the northern hemisphere, and between the pandemic and the polar vortex, we’re getting pretty tired of staring at the same four walls and eating incessantly. It’s the perfect recipe for trying something new and low-calorie, like baking a loaf of bread-shaped note paper from the stuff in the recycling bin.

[SusanLand] likes to make paper out of whatever discarded things she has on hand, including old jeans. When she tried making paper out of nothing but toilet paper tubes, it didn’t work so well, but it gave her an idea for cooking up some offbeat stationery. She beefed up the pulp with shredded office paper and corn starch, and dialed in the whole wheat hue with a pinch of yellow and orange paper. Once the pulp was ready, she poured it into bread-shaped molds made from a plastic milk jug.

This tidy introduction to making your own paper covers everything from pulping techniques to drying methods. Once the slices are dry, [SusanLand] embellishes them with a scoring tool, colored pencils, and a handful of seeds to complete the look. Check out that process in the videos after the break.

Don’t want to make paper out of your paper? Use it to weigh your car, or fold up a fleet of airplanes.

Continue reading “DIY Bread Slice Paper Goes Against The Grain” →

Minimal MQTT With Micropython

February 17, 2021 by Chris Lott 16 Comments

I have been meaning to play around with MQTT for some time now, and finally decided to take the plunge one evening last week. I had three cheap home temperature and humidity sensors, and was bothered that they often didn’t agree. Surprisingly, while the analog one had a calibration adjustment in the back, I have no idea how to calibrate the two digital ones. I took this as a sign that it was time to learn MQTT and be able to install my own, accurate sensors. Of course, I began by ordering the cheapest sensors I could find, but I can always upgrade later on.

While we have written quite a bit about MQTT in Hackaday, I had to go all the way back to 2016 to find this introductory four-part series by Elliot Williams. Five years is a long time in the tech world, but I decided to give it a try anyway. Continue reading “Minimal MQTT With Micropython” →

Software Challenge’s Solution Shows Reverse Engineering In Action

February 16, 2021 by Donald Papp 3 Comments

[0xricksanchez] participated in a software reverse-engineering challenge and recently wrote up the solution, and in so doing also documented the process used to discover it. The challenge was called Devil’s Swapper, and consisted of a small binary blob that output a short message when executed. The goal of the challenge? Discover the secret key and the secret message within. [0xricksanchez]’s writeup, originally intended just as a personal record, ended up doing an excellent job of showing how a lot of reverse engineering tools and processes get applied to software in a practical way.

What’s also great about [0xricksanchez]’s writeup is that it uses standard tools and plenty of screenshots to show what is being done, while also explaining why those actions are being chosen and what is being learned. It’s easy to follow the thought process as things progress from gathering information, to chasing leads, and finally leveraging what’s been learned. It’s a fascinating look into the process of applying the reverse engineering mindset to software, and a good demonstration of the tools. Give it a read, and see how far you can follow along before learning something new. Want more? Make sure you have checked out the Hackaday 2020 Remoticon videos on reverse engineering firmware, and doing the same for PCBs.

Using MIDI To Solve A Keyboard Shortcut Problem

February 16, 2021 by Donald Papp 4 Comments

[Pete] admits that his MIDI-based slide advance alert system is definitely a niche solution to a niche problem, but it is a wonderful example of using available tools to serve a specific need. The issue was this: [Pete] is involved in numerous presentations streamed over video, and needed a simple and effective way for the Presenter to notify the Producer (the one responsible for the video streaming and camera switching) to discreetly advance slides on cue.

To most of us, this is a simple problem to solve. Provide the presenter with a USB macro keyboard to trigger the keyboard shortcuts for slide advancement, and the job’s done. But that didn’t quite cut it for [Pete]. In their situation, the Producer is managing more than just the slides as they switch between cameras, watch the chat window, and manage the video streaming itself. Triggering slide advancement via keyboard shortcuts only works if the presentation software is in focus when the buttons are pressed, which isn’t guaranteed.

[Pete’s] solution was to make a small two-button device (one button for next slide, one for previous slide) that uses MIDI to communicate with a small custom application on the producer’s machine, and doesn’t care about application focus. Pressing the slide advance button plays a distinct tone into the producer’s headphones, plus the custom application displays “Forward”, “Back”, or “Waiting” in a window, depending on the state of the Presenter’s buttons. The design is available on Instructables for anyone wanting a closer look.

[Pete] reports that it works and it’s far more discreet than saying “next slide, please” twenty or more times per presentation. You may notice from the photo that LEGO bricks play a prominent part in the device, and if you’d like to see more of that sort of thing, make sure to check out these other brick-mountable PCB designs.

Learn Bil Herd’s DIY Surface Mount Assembly Process

February 2, 2021 by Bil Herd 40 Comments

You can do your own Surface Mount Technology based PCB assembly with just a handful of tools and some patience. At the heart of my SMT process is stopping to inspect the various steps all while trying to maintain a bit of cleanliness in the process.

Surface mount or Surface Mount Technology (SMT) is the modern way to assemble Printed Circuit Boards (PCB) and is what is commonly seen when opening a modern piece of tech. It’s much smaller than the older Through-Hole (TH) technology where the component leads were inserted into holes in PCB, and act we called “stuffing” since we had to stuff the components into the holes.

A few specialized tools make this a lot easier, but resourceful hackers will be able to pull together a solder paste stencil jig, vacuum tweezers, and a modified toaster oven with a controller that can follow the reflow profile of the solder paste. Where you shouldn’t skimp is on the quality, age, and storage of the solder paste itself.

Join me after the break for my video overview of the process I use in my workshop, along with details of every step of my SMT assembly process.

Continue reading “Learn Bil Herd’s DIY Surface Mount Assembly Process” →

Two-Key Keyboard Build Log Starts Small, But Thinks Big

January 23, 2021 by Donald Papp 3 Comments

Interested in making a custom keyboard, but unsure where to start? Good news, because [Jared]’s build log for an adorable “2% Milk” two-key mini-keyboard covers everything you need to know about making a custom keyboard, including how to add optional RGB lighting. The only difference is that it gets done in a smaller and cheaper package than jumping directly in with a full-size DIY keyboard.

[Jared] is definitely no stranger to custom keyboard work, but when he saw parts for a two-key “2% Milk” keyboard for sale online, he simply couldn’t resist. Luckily for us, he took plenty of photos and his build log makes an excellent tutorial for anyone who wants to get into custom keyboards by starting small.

The hardware elements are clear by looking at photos, but what about the software? For that, [Jared] uses a ~~Teensy~~ Pro Micro clone running QMK, an open source project for driving and configuring custom input devices. QMK drives tiny devices like the 2% Milk just as easily as it does larger ones, so following [Jared]’s build log therefore conveys exactly the same familiarity that would be needed to work on a bigger keyboard, which is part of what makes it such a great project to document.

Interested in going a little deeper down the custom keyboard rabbit hole? You can go entirely DIY, but there’s also no need to roll everything from scratch. It’s possible to buy most of the parts and treat the project like a kit, and Hackaday’s own [Kristina Panos] is here to tell you all about what that was like.