More Homemade PCB Tinning

[Marko] styles himself as a crazy chemist. His video showing a fast tin plating solution for PCBs (YouTube, see below) doesn’t seem so crazy. We will admit, though, it uses some things that you might have to search for.

The formula calls for stannous chloride — you could probably make this by dissolving tin in hydrochloric acid. There’s also thiourea — the main chemical in silver-cleaning dips like Tarn-X. Sulphuric acid and deionized water round out the recipe.

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Tinning Solution From the Hardware Store

Making your own printed circuit board at home often leads to a board which looks homemade. Exposed copper is one of the tell-tale signs. That may be your aesthetic and we won’t cramp your style, but exposed copper is harder to solder than tinned copper and it likes to oxidize over time. Tinning at home can bring you a step closer to having a full-featured board. In the video after the break, famed chemist [nurdrage] shows us how to make tinning solution at home in the video below the break.

There are only three ingredients to make the solution and you can probably find them all at a corner hardware store.

  • Hydrochloric acid. Also known as muriatic acid.
  • Solid lead-free solder with ≥ 95% tin
  • Silver polish containing thiourea

Everything to pull this off is in the first three minutes of the video. [nurdrage] goes on to explain the chemistry behind this reaction. It doesn’t require electricity or heat but heat will speed up the reactions. With this kind of simplicity, there’s no reason to make untinned circuit boards in your kitchen anymore. If aesthetics are very important, home tinning yourself allows you to mask off certain regions and have exposed copper and tin on the same board.

[nurdrage] is no stranger to Hackaday, he even has an article here about making your own PCB etchants and a hotplate to kick your PCB production into high gear.

Thanks for the tip, [drnbutyllithium].

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The Art of Blinky Business Cards

Business cards are stuck somewhere between antiquity and convenience. On one hand, we have very convenient paperless solutions for contact swapping including Bluetooth, NFC, and just saying, “Hey, put your number into my phone, please.” On the other hand, holding something from another person is a more personal and memorable exchange. I would liken this to the difference between an eBook and a paperback. One is supremely convenient while the other is tactile. There’s a reason business cards have survived longer than the Rolodex.

Protocols and culture surrounding the exchange of cards are meant to make yourself memorable and a card which is easy to associate with you can work long after you’ve given your card away. This may seem moot if you are assigned cards when you start a new job, but personal business cards are invaluable for meeting people outside of work and you are the one to decide how wild or creative to make them.

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Print A Flexible Keypad

[Micah Elizabeth Scott] needed a custom USB keyboard that wrapped around a post. She couldn’t find exactly what she wanted so she designed and printed it using flexible Nijaflex filament. You can see the design process and the result in the video below.

The electronics rely on a Teensy, which can emulate a USB keyboard easily. The keys themselves use the old resistor divider trick to allow one analog input on the Teensy to read multiple buttons. This was handy, but also minimized the wiring on the flexible PCB.

The board itself used Pyralux that was milled instead of etched. Most of the PCB artwork was done in KiCAD, other than the outline which was done in a more conventional CAD program.

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An Hour to Surface Mount

Most of us have made the transition from through hole parts to surface mount. There are lots of scattered tutorials, but if you want to learn some techniques or compare your technique to someone else’s, you might enjoy [Moto Geek’s] hour-long video on how he does surface mount with reflow soldering. You can see the video below.

What makes the video interesting is that it is an hour long and covers the gamut from where to get cheap PCBs, to a homebrew pick and place pencil. [Moto Geek] uses a stencil with solder paste, and he provides links to the materials he uses. Continue reading “An Hour to Surface Mount”

540 PCBs Make a Giant LED Cube

Just about anyone can make a simple LED cube. But what if you want to make a 1-meter cube using 512 LEDs? [Hari] wanted to do it, so he created two different kinds of LED boards using EasyEDA. There are 270  of each type of board, for a total of 540 (there are only 512 LEDs, so we guess he got some spares due to how the small boards panelized). The goal is to combine these boards to form a cube measuring over three feet on each side.

To simplify wiring, the boards are made to daisy chain like a cordwood module. However, to get things to line up, each column of LED boards have to rotate 90 degrees. You can see several videos about the project below.

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Retrotechtacular: Tinkertoy and Cordwood in the Pre-IC Era

It is widely accepted that Gutenberg’s printing press revolutionized thought in Europe and transformed the Western world. Prior to the printing press, books were rare and expensive and not generally accessible. Printing made all types of written material inexpensive and plentiful. You may not think about it, but printing–or, at least, printing-like processes–revolutionized electronics just as much.

In particular, the way electronics are built and the components we use have changed a lot since the early 1900s when the vacuum tube made amplification possible. Of course, the components themselves are different. Outside of some specialty and enthusiast items, we don’t use many tubes anymore. But even more dramatic has been how we build and package devices. Just like books, the key to lowering cost and raising availability is mass production. But mass producing electronic devices wasn’t always as easy as it is today.

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