Cheap Stereo Microscope Helps With SMD

Soldering is best done under magnification. Parts become ever smaller and eyes get weaker, so even if you don’t need magnification now, you will. [Makzumi] didn’t want to shell out $400 or more for a good microscope so he hacked one from some cheap binoculars from the toy section on Amazon.

A lot of magnifiers aren’t really good for soldering because the distance between the work and the lens isn’t very large. The hacked ‘scope has about 4 inches of working distance, which is plenty of room to stick some solder and a hot iron under there. The resulting magnification is about 12 or 15X and he claims that the cell phone pictures he’s included aren’t as good as really looking through the eyepieces yourself.

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Field Expedient Soldering Iron Will Do In A Pinch

If you think [Dubious Engineering]’s moniker is just a name, have a look at the pretty terrible soldering iron hacked out of a lighter in the video below. No one is suggesting this is a good idea but in an emergency, maybe it would come in handy. We liked the use of a chopstick and the formation of a heat exchanger with the copper wire coil. It was a mild disappointment that you had to drill out the chopstick, but we think you could have figured out a different method with a little thought.

The use of duct tape, of course, lends it instant hacker credibility. We suppose this might be useful not just after the robot uprising, but if you had to make a few quick solder joints far away from power and you don’t have a battery-operated iron.

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Workbench Fume Extractor Sucks, But Has A Charming Personality

Shop safety is important regardless of what kind of work you do. For those of us soldering, that means extracting the noxious fumes released by heating up the solder flux used in our projects. [yesnoio] brings to us his own spin on the idea of a fume extractor, and it pulls out all stops with bells and whistles to spare.

The Workbench Assistant bot, as [yesnoio] describes it, is an integrated unit mounted atop a small tripod which extends over the working area where you’re soldering. Inside the enclosure are RGBW lights, an IR camera, and an Adafruit ItsyBitsy M4 Express driving the whole show. Aside from just shining a light onto your soldering iron though, the camera senses thermal activity from it to decide when to ramp up the server-grade fan inside which powers the whole fume extraction part of the project.

But the fun doesn’t stop there, as [yesnoio] decided to go for extra style points. The bot also comes with an amplified speaker, playing soundbites whenever actions such as starting or stopping the fan are performed. These soundbites are variations on a theme, like classic Futurama quotes or R2-D2’s chattering from Star Wars. The selectable themes are dubbed “performers”, and they can be reprogrammed easily using CircuitPython. This is a neat way to give your little desktop assistant some personality, and a fun way to break up the monotony of soldering up all those tiny SMD components on your next prototype.

If even after all this you still need more than just a cute little robotic voice beeping at you to convince you to get a fume extractor for your bench, then maybe some hands-on results could give you that little push you need. And if you’re already convinced and want to build your own, there is no shortage of DIY solutions we’ve seen around here at Hackaday. Check out this one in action after the break!

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BGA Hand Soldering Uses Tombstone Resistor Technique, Demands Surgical Precision

Most Hackaday readers will be a pretty dab hand with a soldering iron. We can assemble surface-mount boards, SOICs and TSSOPs are a doddle, 0402s we take in our stride, and we laugh in the face of 0201s. But a Twitter thread from [Greg Davill] will probably leave all but the most hardcore proponents of the art floundering, as he hand-wires a tiny FPGA in a BGA package to the back of a miniature dot-matrix LED display module.

Resistors soldered on-end, awaiting wires to connect to the BGA microcontroller

As far as we can see the module must once have had its own microcontroller which has been removed. We’d guess it was under an epoxy blob but can’t be sure, meanwhile its pads are left exposed. The Lattice LP1k49 fits neatly into the space, but a web of tiny wires are required to connect it to those pads. First, [Greg] populates the pads with a set of “tombstoned” tiny (we’re guessing 0R) resistors, then wires them to the pads with 30μm wire. He describes a moment of confusion as he attempts to tin a stray hair, which burns rather than accepting the solder.

The result is a working display with a new brain, which surprises even him. We’ve seen more than one BGA wiring over the years, but rarely anything at this scale.

It’s worth mentioning that [Greg] was behind the FLIR frame grabber that was a runner-up in last year’s Hackaday Prize. We admire the photos he’s able to get of all of his projects and aspire to reach this level with our own. Take this as inspiration and then check out the Hackaday contest for Beautiful Hardware images happening right now.

Thanks [Sophi] for the tip.

Homemade Magic Makes The Metcal Go

First soldering irons are often of the Radioshack or Maplin firestarter variety. They’re basically wall power shorted across a nichrome heater or similar with some inline resistance to make it harder to burn down the house. You plug them in, the current flows, and they get hot. Done.

If you stick with the hobby for a while, these eventually get replaced with something like the venerable HAKKO FX-888D or that one Weller everyone likes with the analog knob. These are much improved; having temperature control leads to a more consistently heated tip and much improved soldering experience.

Entering the electronics workplace one comes across the next level of quality soldering iron: high end HAKKOs, Metcals, JBCs, and the like. Using one of these irons is practically a religious experience; they heat in a flash and solder melts while you blink. They even turn off when you put the handpiece down! But they’re expensive to buy (hint: think used). What’s a hobbyist to do?

[SergeyMax] seems to have had this problem. He bit the bullet, figured out how the Metcal works, and made his own base. This is no mean feat as a Metcal might look like a regular iron but it’s significantly more complex than ye olde firestarter. The Metcal magic is based on a oscillating magnetic fields (notice the handpiece is connected via BNC?) interacting with a tip bearing a special coating. In the presence of the changing field the tip heats up until it hits its Curie temperature, at which point it stops interacting with the magnetic field and thus stops heating.

When the user solders, the tip cools by sinking its heat into the part and drops below the Curie temperature again, which starts the heating again. It’s like temperature control with the sensor placed absolutely as close to the part as possible and a nearly instant response time, without even a control loop! [SergeyMax] has a much more thorough description of how these irons work, which we definitely recommend reading.

So what’s the hack? Based on old schematics and some clever reverse engineering from photos [SergeyMax] built a new base station! The published schematic is as rich with capacitors and inductors as one could hope. He didn’t post source or fab files but we suspect the schematic and photos of the bare board combined with some tinkering are enough for the enterprising hacker to replicate.

The post contains a very thorough description of the reverse engineering process and related concerns in designing a cost efficient version of the RF circuitry. Hopefully this isn’t the last Metcal replacement build we see! Video “walkthrough” after the break.

Edit: I may have missed it, but eagle eyed commentor [Florian Maunier] noticed that [SergeyMax] posted the sources to this hack on GitHub!

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Solder SMDs With A Pan O’ Sand

For those that grew up working with through-hole components, surface mount parts can be challenging to deal with. However, there are plenty of techniques out there that are more than accessible to the DIY set. With the right gear, soldering SMD boards is a snap – just get yourself a hot pan of sand (Youtube link, embedded below)!

The process starts with a professionally manufactured PCB, and accompanying stencil. All major PCB CAD packages are capable of generating stencil files these days, and many manufacturers will throw in a laser cut stencil for minimal extra cost with a PCB order. The board is first mounted on a stable surface, and has solder paste applied, before components are placed with tweezers. Perfect placement isn’t necessary, as the surface tension of the molten solder pulls components into their correct orientations. The populated board is then placed on a bed of sand in a frying pan, which is placed on an induction cooktop. The board is then heated until the solder melts, and all the components are neatly reflowed. Once allowed to cool, the board is done!

The trick is that the sand helps evenly heat the circuit board, while keeping it a safe distance away from the heat source. Results are good, and the process is far quicker than hand soldering. It’s easy to keep an eye on the process too. Of course, the traditional method is still to use the humble toaster oven, but new techniques are always useful. We’ve seen it done with a Bunsen burner, too. Video after the break.

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The Fascinating World Of Solder Alloys And Metallurgy

Solder is the conductive metal glue that one uses to stick components together. If you get the component and the PCB hot enough, and melt a little solder in the joint, it will stay put and conduct reliably. But it’s far from simple.

There are many different solder alloys, and even the tip of the soldering iron itself is a multi-material masterpiece. In this article, we’ll take a look at the metallurgy behind soldering, and you’ll see why soldering tip maintenance, and regular replacement, is a good idea. Naturally, we’ll also touch upon the role that lead plays in solder alloys, and what the effect is of replacing it with other metals when going lead-free. What are you soldering with? Continue reading “The Fascinating World Of Solder Alloys And Metallurgy”