On the left, an image of a COB on the multimeter's PCB. On the right, a QFP IC soldered to the spot where a COB used to be, with pieces of magnet wire making connections from the QFP's pins to the PCB tracks.

Epoxy Blob Excised Out Of Broken Multimeter, Replaced With A QFP

September 25, 2022 by Arya Voronova 16 Comments

The black blobs on cheap PCBs haunt those of us with a habit of taking things apart when they fail. There’s no part number to look up, no pinout to probe, and if magic smoke is released from the epoxy-buried silicon, the entire PCB is toast. That’s why it matters that [Throbscottle] shared his journey of repairing a vintage multimeter whose epoxy-covered single-chip-multimeter ICL7106 heart developed an internal reference fault. When a multimeter’s internal voltage reference goes, the meter naturally becomes useless. Cheaper multimeters, we bin, but this one arguably was worth reviving.

[Throbscottle] doesn’t just show what he accomplished, he also demonstrates exactly how he went through the process, in a way that we can learn to repeat it if ever needed. Instructions on removing the epoxy coating, isolating IC pins from shorting to newly uncovered tracks, matching pinouts between the COB (Chip On Board, the epoxy-covered silicon) and the QFP packages, carefully attaching wires to the board from the QFP’s legs, then checking the connections – he went out of his way to make the trick of this repair accessible to us. The Instructables UI doesn’t make it obvious, but there’s a large number of high-quality pictures for each step, too.

The multimeter measures once again and is back in [Throbscottle]’s arsenal. He’s got a prolific history of sharing his methods with hackers – as far back as 2011, we’ve covered his guide on reverse-engineering PCBs, a skillset that no doubt made this repair possible. This hack, in turn proves to us that, even when facing the void of an epoxy blob, we have a shot at repairing the thing. If you wonder why these black blobs plague all the cheap devices, here’s an intro.

We thank [electronoob] for sharing this with us!

Git Intro For Hardware Hackers

September 12, 2022 by Arya Voronova 20 Comments

Git is a wonderful tool that can multiply your project’s impact, or make your project easier to manage by an order of magnitude. Some of us hackers don’t yet know how to use command-line Git, but a relatable example of why a certain tool would be useful might be a good start. Today, I’d like to give you a Git crash course – showing you why and how to put a KiCad PCB into a Git repository, later to be shared with the world.

KiCad works wonderfully with Git. The schematic and PCB files of KiCad are human-readable, especially when compared to other PCB file formats. KiCad creates different files for different purposes, each of them with a well-defined role, and you can make sense of every file in your project folder. What’s more, you can even modify KiCad files in a text editor! This is exactly the kind of use case that Git fits like a glove.

Not Just For Software Developers

What’s Git about, then? Fundamentally, Git is a tool that helps you keep track of code changes in a project, and share these changes with each other. Intended for Linux kernel development as its first target, this is what it’s been designed for, but it’s flexibility extends far beyond software projects. We hardware hackers can make use of it in a variety of ways – we can store PCB and other design software files, blog articles, project documentation, personal notes, configuration files and whatever else that even vaguely fits the Git modus operandi. Continue reading “Git Intro For Hardware Hackers” →

The modem in question plugged into a black powerbank.

Hackable $20 Modem Combines LTE And Pi Zero W2 Power

August 3, 2022 by Arya Voronova 188 Comments

[extrowerk] tells us about a new hacker-friendly device – a $20 LTE modem stick with a quadcore CPU and WiFi, capable of running fully-featured Linux distributions. This discovery hinges on a mountain of work by a Chinese hacker [HandsomeYingYan], who’s figured out this stick runs Android, hacked its bootloader, tweaked a Linux kernel for it and created a Debian distribution for the stick – calling this the OpenStick project. [extrowerk]’s writeup translates the [HandsomeYingYan]’s tutorial for us and makes a few more useful notes. With this writeup in hand, we have unlocked a whole new SBC to use in our projects – at a surprisingly low price!

At times when even the simplest Pi Zero is unobtainium (yet again!), this is a wonderful find. For a bit over the price of a Zero 2W, you get a computer with a similar CPU (4-core 1GHz A53-based Qualcomm MSM8916), same amount of RAM, 4GB storage, WiFi – and an LTE modem. You can stick this one into a powerbank or a wallwart and run it at a remote location, make it into a home automation hub, or perhaps, process some CPU-intensive tasks in a small footprint. You can even get them with a microSD slot for extra storage – or perhaps, even extra GPIOs? You’re not getting a soldering-friendly GPIO header, but it has a few LEDs and, apparently, a UART header, so it’s not all bad. As [extrowerk] points out, this is basically a mobile phone in a stick form factor, but without the display and the battery.

Now, there’s caveats. [extrowerk] points out that you should buy the modem with the appropriate LTE bands for your country – and that’s not the only thing to watch out for. A friend of ours recently obtained a visually identical modem; when we got news of this hack, she disassembled it for us – finding out that it was equipped with a far more limited CPU, the MDM9600. That is an LTE modem chip, and its functions are limited to performing USB 4G stick duty with some basic WiFi features. Judging by a popular mobile device reverse-engineering forum’s investigations (Russian, translated), looks like the earlier versions of this modem came with the way more limited MDM9600 SoC, not able to run Linux like the stick we’re interested in does. If you like this modem and understandably want to procure a few, see if you can make sure you’ll get MSM8916 and not the MDM9600.

Days of using WiFi routers to power our robots are long gone since the advent of Raspberry Pi, but we still remember them fondly, and we’re glad to see a router stick with the Pi Zero 2W oomph. We’ve been hacking at such sticks for over half a decade now, most of them OpenWRT-based, some as small as an SD card reader. Now, when SBCs are hard to procure, this could be a perfect fit for one of your next projects.

Update: in the comments below, people have found a few links where you should be able to get one of these modems with the right CPU. Also, [Joe] has started investigating the onboard components!

Re-Creating The Unique Look Of Unobtainable Aerochrome Film

August 1, 2022 by Donald Papp 23 Comments

Ever heard of Aerochrome? It’s a unique type of color infrared film, originally created for the US military and designed for surveillance planes. Photos taken with Aerochrome film show trees and other vegetation in vivid reds and pinks, creating images that aren’t quite like anything else.

A modified method of trichrome photography is the key behind re-creating that unique Aerochrome look. Click to enlarge.

Sadly, Aerochrome hasn’t been made for over a decade. What’s an enterprising hacker with a fascination for this unobtainable film to do? [Joshua] resolved to recreate it as best he could, and the results look great!

Aerochrome isn’t quite the same as normal film. It is sensitive to infrared, and photos taken with it yield a kind of false color image that presents infrared as red, visible reds as greens, and greens are shown as blue. The result is a vaguely dreamy looking photo like the one you see in the header image, above. Healthy vegetation is vividly highlighted, and everything else? Well, it actually comes out pretty normal-looking, all things considered.

Why does this happen? It’s because healthy, leafy green plants strongly absorb visible light for photosynthesis, while also strongly reflecting near-infrared. This is the same principle behind the normalized difference vegetation index (NDVI), a method used since the 70s to measure live green vegetation, often from satellite imagery.

Aerochrome may be out of production, but black and white infrared film is still available. [Joshua] found that he could re-create the effect of Aerochrome with an adaptation of trichrome photography: the process of taking three identical black and white photos, each using a different color filter. When combined, the three photos (acting as three separate color channels) produce a color image.

To reproduce Aerochrome, [Joshua] takes three monochromatic photos with his infrared film, each with a different color filter chosen to match the spectral sensitivities of the original product. The result is a pretty striking reproduction of Aerochrome!

But this method does have some shortcomings. [Joshua] found it annoying to fiddle with filters between trying to take three identical photos, and the film and filters aren’t really an exact match for the spectral sensitivities of original Aerochrome. He also found it difficult to nail the right exposure; since most light meters are measuring visible light and not infrared, the exposure settings were way off. But the results look pretty authentic, so he’s counting it as a success.

We loved [Joshua]’s DIY wigglecam, and we’re delighted to see the work he put into re-creating an authentic Aerochrome. Fantastic work.

Digital “Toy” Camera, Made For Tilt-Shift And Other Analog-Like Experimenting

July 23, 2022 by Donald Papp 5 Comments

Like many others, [volzo] loves playing with photography in a playful and experimental way. Oddball lenses, vintage elements, and building from kits is what that world looks like. But that kind of stuff is really the domain of film cameras, or at least it was until [volzo] created his Digital Toy Camera design. The result? A self-built, lomography-friendly digital camera that allows for all kinds of weird and wonderful attachments and photo shenanigans.

3D-printed mounts and magnetic attachment makes swapping parts a breeze.

To make a DIY digital camera that allowed that kind of play, the first problem [volzo] had to solve was deciding on an image sensor. It turns out that sourcing image sensors as an individual is a pretty cumbersome process, and even if successful, one still needs to write a driver and create things from the ground up. So, the guts of [volzo]’s creations use the Raspberry Pi and camera sensor ecosystem and M12 lenses, a decision that allows him to focus on the rest of the camera.

3D printing, a bit of CNC machining, and some clever design yields a “toy” camera: simple, inexpensive, and enabling one to take a playful and experimental approach to photography. The design files are available on GitHub, and there are some neat elements to the design. Magnetic mounts allow for easy swapping of lens assemblies, and a M12 x 0.75 tap cuts perfect threads into 3D-printed pieces for M12 lenses.

Heat-set inserts also provide robust fastening that can hold up to disassembly and re-assembly (and don’t miss that our own [Joshua Vasquez] has shared how best to design for and use heat-set inserts.)

[volzo] has a fantastic video to accompany his project; give it a watch (embedded below, under the page break) and see if you don’t come away with some inspiration of your own.

Continue reading “Digital “Toy” Camera, Made For Tilt-Shift And Other Analog-Like Experimenting” →

The word clock on a desk, with "tien", "over", "half" and "twaalf" lit

An Impeccably Documented Word Clock In Dutch

July 18, 2022 by Arya Voronova 8 Comments

[Maarten Pennings] shares a word clock project – but not the regular kind. For a start, this clock is a shining demonstration of hobbyist-available 3D printing technologies, with embedded light guides for the letters printed in transparent filament, thanks to a dual-extruder printer. For a word clock, it’s surprisingly small – in fact, it uses an 8×8 addressable LED matrix, with words shown in different colors. If you’re looking to build a novel word clock, you’re all set here – [Maarten] tells all about this project’s story and provides a treasure trove of insights into designing all of its aspects!

The 8×8 limitation was initially set because he wanted to use a low-cost MAX7219 8×8 LED matrix module as a base for the clock. Thankfully, in Dutch, time can be expressed using shorter words — still, it had to be limited to 5-minute intervals. Extra effort had to be spent designing the layout — [Maarten] mentions his friend writing a solver that found a way to fit some words onto the layout diagonally. At some point, he switched from LEDs to Neopixels, and dug deep into addressable LED technology. For instance, he demonstrates Neopixel power measurements and current consumption calculations. This shows that the calculations indeed match the clock’s real consumption when measured by an external meter.

In the best of hacker traditions, all the source files are on Github — if you fancy yourself a Dutch word clock, you can build [Maarten]’s design easily! He provides extensive instructions on building this clock in the README, including a flashing and configuration tutorial, complete wiring diagrams, and a soldering guide. A manufacturing-grade amount of build information that won’t leave you guessing. He’s also added a fair number of animations, put plenty of effort into clock precision verification, and even investigated some Neopixel protocol minutiae. All in all, our hacker went all in on the capabilities while embracing the constraints. This reminds us of the similarly well-documented haptic word clock we covered just a year ago – check that one out, too!

Continue reading “An Impeccably Documented Word Clock In Dutch” →

Got A Cardboard Box? Get Into Food Smoking!

July 15, 2022 by Donald Papp 17 Comments

We appreciate a good kitchen hack, and we have always liked TV personality and chef [Alton Brown]’s McGuyver-ish approach to these things. So for anyone who hasn’t seen it, let’s take a moment to highlight how to make (and use) Alton Brown’s Cardboard Box Smoker.

[Alton] himself confesses that over the years it has remained his favorite smoker for a few good reasons. The price is certainly right, but there are a few other things that really stand out in the design. It’s easy to assemble and take down, needing very little storage space compared to a purpose-built smoker. It’s also trivial to monitor the temperature inside: just poke a thermometer probe through the side of the box. Finally, it’s a great way to get some additional use out of an old hot plate and cast iron pan. It’s the kind of thing one could put together from a garage sale and a visit to the dollar store.

The cardboard box is perfectly serviceable, but one may be tempted to kick it up a notch with some upgrades. In that case, check out this tech-upgraded flower pot smoker (also based on an Alton Brown design.)

Reusing and repurposing is a great way to experiment in the kitchen without needing to buy specialized equipment. Here’s another example: Kyoto-style cold brew coffee. It’s thick and rich and brings out different flavor profiles. Curious? Well, normally it requires a special kind of filter setup, but it can also be accomplished with cheesecloth, coffee filters, and a couple of cut-up soft drink bottles. Oh, and some rubber bands and chopsticks if things are too wobbly. Just do yourself a favor and use good quality coffee beans, or better yet, roast them yourself. Just trust us on this one.