Pocket CO2 Sensor Doubles As SMD Proving Ground

While for some of us it’s a distant memory, every serious electronics hobbyist must at some point make the leap from working with through-hole components to Surface Mount Devices (SMD). At first glance, the diminutive components can be quite intimidating — how can you possibly work with parts that are literally smaller than a grain of rice? But of course, like anything else, with practice comes proficiency.

It’s at this silicon precipice that [Larry Bank] recently found himself. While better known on these pages for his software exploits, he recently decided to add SMD electronics to his repertoire by designing and assembling a pocket-sized CO2 monitor. While the monitor itself is a neat gadget that would be worthy of these pages on its own, what’s really compelling about this write-up is how it documents the journey from SMD skeptic to convert in a very personal way.

A fine-tipped applicator will get the solder paste where it needs to go.

At first, [Larry] admits to being put off by projects using SMD parts, assuming (not unreasonably) that it would require a significant investment in time and money. But eventually he realized that he could start small and work his way up; for less than $100 USD he was able to pick up both a hot air rework station and a hotplate, which is more than enough to get started with a wide range of SMD components. He experimented with using solder stencils, but even there, ultimately found them to be an unnecessary expense for many projects.

While the bulk of the page details the process of assembling the board, [Larry] does provide some technical details on the device itself. It’s powered by the incredibly cheap CH32V003 microcontroller — they cost him less than twenty cents each for fifty of the things — paired with the ubiquitous 128×64 SSD1306 OLED, TP4057 charge controller, and a SCD40 CO2 sensor.

Whether you want to build your own portable CO2 sensor (which judging from the video below, is quite nice), or you’re just looking for some tips on how to leave those through-hole parts in the past, [Larry] has you covered. We’re particularly eager to see more of his work with the CH32V003, which is quickly becoming a must-have in the modern hardware hacker’s arsenal.

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A freshly reballed BGA chip next to a clean PCB footprint

Working With BGAs: Soldering, Reballing, And Rework

In our previous article on Ball Grid Arrays (BGAs), we explored how to design circuit boards and how to route the signals coming out of a BGA package. But designing a board is one thing – soldering those chips onto the board is quite another. If you’ve got some experience with SMD soldering, you’ll find that any SOIC, TQFP or even QFN package can be soldered with a fine-tipped iron and a bit of practice. Not so for BGAs: we’ll need to bring out some specialized tools to solder them correctly. Today, we’ll explore how to get those chips on our board, and how to take them off again, without spending a fortune on equipment.

Tools of the Trade

For large-scale production, whether for BGA-based designs or any other kind of SMD work, reflow ovens are the tool of choice. While you can buy reflow ovens small enough to place in your workshop (or even build them yourself), they will always take up quite a bit of space. Reflow ovens are great for small-scale series production, but not so much for repairs or rework. Continue reading “Working With BGAs: Soldering, Reballing, And Rework”

PnPAssist: A “Smart” Build Platform For Manual PCB Assembly

Open source pick and place machines have come a long way in the past years, but are not necessarily worth the setup time and machine cost if you are only building a few PCBs at a time. [Nuri Erginer] found himself in this situation regularly, so he created PnPAssist, a “smart” build platform to speed up manual PCB assembly. Video after the break.

The PnP assist consists of a small circular platform that can automatically translate and rotate to place the current footprint in the middle of the platform, right in the center of your microscope’s view, and a laser crosshair. The entire device can also rotate freely on its base to avoid contorting your arm to match the footprint orientation. Just export the PnP file from your favorite PCB design software, load it on a micro SD card, plug it into the PnPAssist, and start assembling. The relevant component information is displayed on a small OLED display right on the machine. [Nuri] has also created a component organizing tray that will indicate the correct compartment with an RGB LED.

Below the build platform, a 3D printed gear is in contact with a pair of parallel lead screws driven by stepper motors. The relative motion of the lead screws allows the platform to rotate, translate, or both. This arrangement also means the machine is a lot more compact than a conventional XY-table and can be packed away when not in use. The base is held firmly in place on the workbench with a set of suction cups or screws. Power is provided through the fixed base using a slip-ring, so there are no cables to twist up as you spin the machine around. Continue reading “PnPAssist: A “Smart” Build Platform For Manual PCB Assembly”

Automatic Component Tape Cutter For When Your Electronics Kit Hits The Big Time

Even for the simplest of products, production at scale can be big challenge. For example, you might find yourself spending many hours manually counting and cutting strips of component tape to go with the DIY electronics kit your selling on Tindie. [Tom Keddie] found himself in similar position some time ago, and built himself an automated component counter and tape cutter.

[Tom] posted the video of his old machine (see it after the break) after a call for help from another Twitter user who found himself with a lot of component strips to cut. The frame of the machine is made from 20×20 aluminium extrusions and laser cut plexiglass. The tape is pulled off the reel by a stepper motor using a 3D printed sprocket, with the tape held on by Lego wheel and tension spring. A second idler sprocket with tensioner is used to guide the tape through two photo-interrupters that can count holes in opaque tape or the components in clear tape. The cutter itself it an Exacto blade mounted on a wooden block in a guillotine-like arrangement, driven by another stepper motor and a threaded rod as lead screw. Everything is of course controlled by an Arduino. Although not used any more, [Tom] says it worked very well in its day.

The availability of cheap laser cutting, 3D printing and components like aluminium extrusions and stepper motors have really made it possible for anyone to add some automation to production in the home workshop. You won’t be surprised that we’ve seen something like this before, but we’ve also seen similar machines for wiring prep and through-hole resistors. Let us hear your production hacks in the comments, or drop us a tip if you’ve documented it!

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Component Shelf Life: How To Use All That Old Junk

There are two types of Hackaday readers: those that have a huge stock of parts they’ve collected over the years (in other words, an enormous pile of junk) and those that will have one a couple of decades from now. It’s easy to end up with a lot of stuff, especially items that you’re likely to use in more than one design; the price breakpoints at quantities of 10 or 100 of something can be pretty tempting, and having a personal stock definitely speeds the hacking process now that local parts shops have gone the way of the dinosaur. This isn’t a perfect solution, though, because some components do have shelf-lives, and will degrade in some way or another over time.

If your stash includes older electronic components, you may find that they haven’t aged well, but sometimes this can be fixed. Let’s have a look at shelf life of common parts, how it can be extended, and what you can do if they need a bit of rejuvenation.

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Freeform Wire Frame Tulip Blooms To The Touch

Holidays are always good for setting a deadline for finishing fun projects, and every Valentine’s Day we see projects delivering special one-of-a-kind gifts. Why buy a perishable bulk-grown biological commodity shipped with a large carbon footprint when we can build something special of our own? [Jiří Praus] certainly seemed to think so, his wife will receive a circuit sculpture tulip that blooms when she touches it.

via @jipraus

This project drew from [Jiří]’s experience with aesthetic LED projects. His Arduino-powered snowflake, with LEDs mounted on a custom PCB, is a product available on Tindie. For our recent circuit sculpture contest, his entry is a wire frame variant on his snowflake. This tulip has 7 Adafruit NeoPixel in the center and 30 white SMD LEDs in the petals, which look great. But with the addition of mechanical articulation, this project has raised the bar for all that follow.

We hope [Jiří] will add more details for this project to his Hackaday.io profile. In the meantime, look over his recent Tweets for more details on how this mechanical tulip works. We could see pictures and short videos of details like the wire-and-tube mechanism that allowed all the petals to be actuated by a single servo, and the components that are tidily packaged inside that wooden base.

Need more digital expressions of love? We have no shortage of hearts. Animated LED hearts, illuminated acrylic hearts, and talking hearts. We’re a little short on flower projects, but we do have X-ray of a rose among others to accompany [Jiří]’s tulip.

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Bumblebee Breakout, A DIY Wearable Connector

The practice of developing wearable electronics offers a lot of opportunity for new connector designs and techniques for embedding electronics. Questions like these will eventually come up: How will this PCB attach to that conductive fabric circuit reliably? What’s the best way to transition from wire to this woven conductive trim? What’s the best way to integrate this light element into this garment while still maintaining flexibility?

Mika Satomi and Hannah-Perner Wilson of Kobakant are innovators in this arena and inspire many with their prolific documentation while they ask themselves questions similar to these. Their work is always geared towards accessibility and the ability to recreate what they have designed. Their most recent documented connector is one they call the Bumblebee Breakout. It connects an SMD addressable RGB LED, such as Adafruit’s Neopixel, to a piece of side glow fiber optic 1.5mm in diameter. On a short piece of tubing, the four pads of the SMD LED are broken out into four copper rings giving it the look of a striped bumblebee. To keep from shorts occurring while wrapping the copper tape contacts around the tube, they use Kapton tape to isolate each layer as they go.

This connector was originally created to be used in a commission they did out of Koba, their e-textile tailor shop located in Berlin. Fiber optics were applied to jackets for a performance called “All Your Base Are Belong To Us” produced by the Puppetry Department of the Hochschule für Schauspielkunst Ernst Busch.

Peruse more e-textiles techniques and learn how to build a connector transitioning from an embroidered thread bus to a wire and how to knit solderable circuit boards. And make sure to click around Kobakant’s website, it’s full of e-textile DIY tutorials!