No Solder! Squeeze Your Parts To The PCB

What’s solder for, anyway? It’s just the stuff that sticks the parts to the PCB. If you’re rapid prototyping, possibly with expensive components, and want to be able to remove chips from the board easily when you spin up the next iteration, it would be great if you didn’t have to de-solder them to move on. If only you could hold the parts without the solder…

That’s exactly the goal behind [Zeyu Yan] et al’s SolderlessPCB, which uses custom 3D printed plastic covers to do the holding. And it has the knock-on benefit of serving as a simple case.

In their paper, they document some clever topologies to make sure that the parts are held down firmly to the board, with the majority of the force coming from screws. We especially like the little hold-down wings for use with SMD capacitors or resistors, although we could absolutely see saving the technique exclusively for the more high value components to simplify design work on the 3DP frame. Still, with the ability to automatically generate 3D models of the board, parts included, this should be something that can be automated away.

The group is doing this with SLA 3D printing, and we imagine that the resolution is important. You could try it with an FDM printer, though. Let us know if you do!

This is the same research group that is responsible for the laser-cut sheet-PCB origami. There’s clearly some creative thinking going on over there.

Switching Converter For EEPROM Programmer Taxes Solderless Breadboard

We all know that solderless breadboards have their limitations. All that stray capacitance can play hell with circuits, especially high-speed stuff, but they’re so darn useful that avoiding them in favor of some other prototyping method can be really hard. So we often just forge ahead, plugging in our parts and hoping for the best

A recent veteran of the breadboard battle is [Anders Nielsen], who kicked off a new project by prototyping this high-voltage boost converter on a breadboard, with mixed results. The project is a scratch-built programmer for old-school ROM chips, a task normally farmed out to a dedicated programmer, but where’s the sport in that? Besides, this is the future, and generating the 12 to 14 volts needed should be a snap. And it would be, except for the fact that his chosen chip, a MIC2288 switching boost regulator, is only available in an SMD package. Getting the chip and a few other SMD support components onto breadboard-compatible breakouts proved to be challenging, and getting it working once it was there was even more work.

A lot of the trouble was down to simple breadboarding errors, but the big problem was the input capacitance, which [Anders] had to fiddle with quite a bit to get the converter to 14 volts. The current maxes out at about 25 mA before the voltage starts dropping, which just might be enough to burn those old chips, so we’ll call this a provisional win and see what happens when he builds the rest of the programmer.

[Anders]’ experience here raises a good question: what’s the best way to prototype using fussy SMD components? PCBs are cheap enough that it’s tempting to go straight to one, but swapping parts in and out like he had to do here to get everything just right would be much harder that way. We’re not sure we know the answer, but we’re pretty sure we’ll hear your thoughts on that in the comments section.

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Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Tri-lingual Typewriter

Isn’t it just fantastic when a project finally does what you wanted it to do in the first place? [Simon Merrett] isn’t willing to compromise when it comes to the Aerodox. His original vision for the keyboard was a wireless, ergonomic split that could easily switch between a couple of PCs. Whereas some people are more into making layout after layout, [Simon] keeps pushing forward with this same design, which is sort of a mashup between the ErgoDox and the Redox, which is itself a wireless version of the ErgoDox.

The Aerodox has three nRF51822 modules — one for the halves to communicate, one for the control half to send key presses, and a third on the receiver side. [Simon] was using two AA cells to power each one, and was having trouble with the range back to the PC.

The NRFs want 3.3 V, but will allegedly settle for 2 V when times are hard. [Simon] added a boost converter to give each a solid 3.3 V, and the Aerodox became reliable enough to be [Simon]’s daily driver. But let’s go back to the as-yet-unrealized potential part.

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Who Needs Pin Headers?

[Martin] sent this query, along with the lead photo, into the tip line, and he makes a good point. Most development and evaluation boards have multiple rows of pin headers, often arriving loose in the package — soldering is left to the user. In an abundance of caution, we usually design our prototype boards with many pin headers for debugging and testing. But as [Martin] reminds us, there are other alternatives to solder.

  • Yours truly once worked with a prolific designer of PIC microprocessor boards. Long before the advent of solutions like the Tag Connect family, [Ralph] would program his boards by just inserting a pin header into the PCB and applying gentle pressure with his thumb until the code finished flashing.
  • You may have seen the staggered offset PCB patterns that hold your pin header securely while you solder. You could tweak this a little bit to put more pressure on the pins, making a solder-less connection that is sufficient for temporary testing.
  • Taking the opposite approach, you can get solderless connectors with press-fit pins, a method we tested a few years ago on a Raspberry Pi Zero. Anyone who has worked on Eurocard-based systems like VME can appreciate the time-savings and improved reliability of 96-pin DIN-41612 press-fit connectors.
  • Or, as [Martin] proposes, you could use one of these inexpensive pogo-pin clamps. These are available for less than $10 from your favorite Asian electronics distributor. They are about the size of a large clothespin, and are available in several different pin configurations.

These techniques won’t help you if you need to plug your board into another card, such as a hat onto a Raspberry Pi. But when you just want to grab a few signals for a serial port or probing some digital I/O signals, having a few of these clips in your tool box can save you the time and headache of soldering down a header. Do you have any tips for making soldering pin headers easier, or even avoiding them altogether? Let us know in the comments below.

Silicon Jumpers Make This Wire-Free Breadboard Programmable

There’s no doubting the utility of the trusty solderless breadboard, but you have to admit they’re less than perfect. They’re not ideal for certain types of circuits, of course, but that’s less of a problem than those jumper wires. The careless will end up with their components hopeless tangled in a rat’s nest of jumpers, while the fastidious will spend far more time making the jumpers neat and tidy than actually prototyping the circuit itself. What to do?

One way to crack this nut is to make the solderless breadboard jumperless, too. That’s the idea behind “breadWare” a work-in-progress undertaken by [Kevin Santo Cappuccio]. The idea is to adapt a standard breadboard so that connections between arbitrary pairs of common contact strips — plus the power rails — can be made in software. The trick behind this is a matrix of analog CMOS switch chips, specifically the MT8816AP. Each chip’s 128 crosspoint switches can handle up ± 12 volts, so there are plenty of circuits that can use these programmable silicon jumpers.

[Kevin] is currently on version 0.2, which is sized to fit under a solderless breadboard and make a compact package. He shared details on how he’s connecting to the breadboard contacts, and it looks like a painful process: pull out the contact, cut a small tab at the gutter-end, and bend it down so it forms a lead for a through-hole in the PCB. It seems like a lot of work, and there must be a better way; [Kevin] is clearly open to suggestions.

While we’ve seen crosspoint switching used to augment solderless breadboarding before, we find this project pleasing in its simplicity. The thought of tossing out all those jumpers is certainly tempting.

[Ben Eater]’s Breadboarding Tips

A solderless breadboard is a place where ideas go to become real for the first time. Usually, this is a somewhat messy affair, with random jumpers flying all about the place, connecting components that can be quickly swapped to zero in on the right values, or to quickly change the circuit topology. Breadboards aren’t the place to make circuit artwork.

That is, however, not always the case, and we’ve seen more than a few examples from [Ben Eater] on breadboarding that approaches the circuit sculpture level of craftsmanship. And like any good craftsman, [Ben] has shared some of his breadboarding tips and tricks in a new video. Starting with a simple 555 blinkenlight project that’s wired up in the traditional anything-goes fashion, [Ben] walks us through his process for making a more presentation-worthy version.

His tools are high-quality but simple, with the wire strippers being the most crucial to good results. Surprisingly, [Ben] relies most heavily on the simple “scissors-style” strippers for their versatility, rather than the complicated semi-automatic tools. We found that to be the biggest take-home from the video, as well as the results of practice. [Ben] has done tons of this type of breadboarding before, which means when he “eyeballs” stripping 0.3 inches of insulation, he can do it down to a ten-thousandth precision.

Granted, there’s not much new here, but watching this video is a little like watching [Bob Ross] paint — relaxing and strangely compelling at the same time. You can get more of the same with pretty much any of his videos that we’ve covered, like this 6502 breadboard computer build. We’ve also seen [Eater]-inspired builds that are pretty impressive, like this full-8-bit breadboard computer.

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Fail Of The Week: Z-Tape Is No Substitute For Solder

Here at Hackaday, we see all kinds of mechanical construction methods. Some are impressively solid and permanent, while others are obviously temporary in nature. The latter group is dominated by adhesives – sticky stuff like cyanoacrylate glue, Kapton tape, and the ever-popular hot glue. They’ve all got their uses in assembling enclosures or fixing components together mechanically, but surely they have no place in making solid electrical connections, right?

Maybe, maybe not. As [Tom Verbeure] relates, so-called Z-tape just might be an adhesive that can stand in for solder under certain circumstances. Trouble is, he couldn’t find the right conditions to make the tape work. Z-tape, more properly called “Electrically Conductive Adhesive Transfer Tape 9703”,  derives its nickname from the fact that it’s electrically conductive, but only in the Z-axis. [Tom] learned about Z-tape in [Joe FitzPatrick]’s malicious hardware prototyping workshop at the 2019 Hackaday Superconference, and decided to put it to the test.

A card from a Cisco router served as a testbed thanks to an unpopulated chip footprint. The 0.5-mm pin spacing on the TSOP-48 chip was within spec for the Z-tape, but the area of each pin was 30 times smaller than the recommended minimum bonding area. While the chip was held down mechanically by the Z-tape, only five of the 48 pins were electrically connected to the pads. Emboldened by the partial success, [Tom] tried a 28-pin SOIC chip next. The larger pins and pads were still six times smaller than the minimum, and while more of the pins ended up connected by the tape, he was unable to make all 28 connections.

Reading the datasheet for the adhesive revealed that constant pressure from a clamp or clip might be necessary for reliable connections, which suggests that gluing down SMD chips is probably not the best application for the stuff. Still, we appreciate the effort, and the fine photomicrographs [Tom] made showing the particles within the Z-tape that make it work – at least in some applications.