Front of PCB for "SMT Garden" with glowing LEDs

Surface Mount Soldering Practice For Budding Electrical Engineers

October 4, 2022 by Abe Connelly 10 Comments

Electronics components are steadily moving away from through hole parts to using surface mount technology (SMT) exclusively. While the small size of the SMT components can be intimidating, with a little practice, soldering can come pretty naturally. To help folks get over their fear of soldering small parts, [Alpenglow Industries] have created a charming board to practice SMT soldering skills on.

[Alpenglow Industries] board, called the “SMT Garden”, combines a variety of SMT sizes ranging from 0402 to 1206 with beautiful PCB artwork to highlight the variety of LEDs on board. [Alpenglow Industries] provides detailed instructions on the various aspects of SMT soldering including what the terminology is and providing various techniques to help in soldering. The boards have practice “stalks” of surface mount component pads, so that folks can practice on columns of similarly sized SMT components to perfect their technique. The training stalks themselves aren’t functional but are there to provide practice for when folks feel comfortable soldering the LEDs, 555 timer and inverter chips to make the board functional.

[Alpenglow Industries] have provided all the KiCAD project files, gerbers and schematics available online. SMT soldering is more accessible than ever and when you can even use your phone as a microscope, it’s a good excuse to try it out, if you haven’t already.

picture showing the re-built scale with an extra blue box with electronics on the bottom of it. on the scale, there's a transparent food-grade plastic glass with measurement marks on the side.

Urine Flow Measurement Made Accessible With UroFlow

September 29, 2022 by Arya Voronova 21 Comments

If you’re dealing with a chronic illness, the ability to continuously monitor your symptoms is indispensable, helping you gain valuable insights into what makes your body tick – or, rather, mis-tick. However, for many illnesses, you need specialized equipment to monitor them, and it tends to be that you can only visit your doctor every so often. Thankfully, we hackers can figure out ways to monitor our conditions on our own. With a condition called BPH (Benign Prostate Hyperplasia), one of the ways to monitor it is taking measurements of urinary flow rate. Being able to take these measurements at home provides better insights, and, having found flow rate measurement devices to be prohibitively expensive to even rent, [Jerry Smith] set out to build his own.

This build is truly designed to be reproducible for anyone who needs such a device. Jerry has intricately documented the project and its inner workings – the 31-page document contains full build instructions, BOM for ordering, PCB description and pinout diagrams, calibration and validation instructions, and even software flowcharts; the GitHub repo has everything else you might need. We’re pleasantly surprised – this amount of documentation isn’t typically seen in hacker projects, and is even more valuable considering that this is a medical device that other hackers in need will want to reproduce.

For the hardware, [Jerry] took a small digital scale of a certain model and reused its load cell-based weighing mechanism using an HX711 amplifier, replacing the screen and adding an extra box for control electronics. With an Arduino MKR1010 as brains of the operation, the hardware’s there to log flow data, initially recorded onto the SD card, with WiFi connectivity to transfer the data to a computer for plotting; a DS3234 RTC breakout helps keep track of the time, and a custom PCB ties all of these together. All of these things are easy to put together, in no small part due to the extensive instructions provided.

Continue reading “Urine Flow Measurement Made Accessible With UroFlow” →

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 17 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 24 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” →