Author: Al Williams

4349 Articles

Homebrew 3D Printer Goop Promises Better Bed Adhesion

December 6, 2022 by 43 Comments

Back when 3D printers were pretty new, most of us had glass beds with or without painter’s tape. To make plastic stick, you’d either use a glue stick or hair spray. Many people have moved on to various other build surfaces that don’t require help, but some people still use something to make the bed sticky and there are quite a few products on the market that claim to be better than normal glue or hairspray. [Jonas] wanted to try it, but instead of buying a commercial product, he found a recipe online for “3D printer goop” and made it himself.

You need four ingredients: distilled water and isopropyl alcohol are easy to find. The other two chemicals: PVP and PVA powder, are not too hard to source and aren’t terribly dangerous to handle. The recipe was actually from [MakerBogans] who documents this recipe as “Super Goop” and has another formula for “Normal Goop.” You’ll probably have to buy the chemicals in huge quantities compared to the tiny amounts you really need.

We assume the shots of the 3D printer printing its first layer is showing how effective the glue is. This looks like a very simple thing to mix up and keep in a sprayer. If you have some friends,  you could probably do a group buy of the chemicals and it would cost nearly nothing for the small amounts of chemicals you need.

If you don’t want to order exotic chemicals, you might not need them. We used to make “goop” by dissolving ABS in acetone, but hairspray usually did the trick.

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Designing To Remove Supports

December 5, 2022 by 22 Comments

If you want to 3D print arbitrary shapes with an FDM printer, you often find you need supports. If you have dissolvable support material, that might not be a big issue, but if you use the same material for support as you print in, removing it can be difficult, depending on the location of the support and your slicer. At the very least, it is going to require more time and filament to print and at least some post-processing. [Slant 3D] asserts that you can always redesign the part using chamfers and fillets to avoid needing support to start with. Watch the video, below.

Of course, sometimes you just need to flip the part around. For example, the part in question — which is just an example — could just be rotated to avoid support, but that isn’t the point, of course. A fillet, however, still might need support, so you wind up having to do a double fillet to really avoid support.

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Dirty TRS-80 Has A Surprise Hack

December 4, 2022 by 12 Comments

[Adrian] had a TRS-80 model IV that looks like it was stored in a mulch pile. However, it seemed to have some surprises. The first hint that something was up was that the keyboard looks like a model III and there are two mystery knobs in the back.

So what’s going on? You” have to watch [Adrian’s] video below to find out. At about the six-minute mark, you’ll find that things are not at all what you might think.

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Miracle Of Science: Scotch Tape Improves Generator

December 4, 2022 by 11 Comments

We were always amused that one of the biggest scientific discoveries of the recent past — graphene — was started with pencil lead and Scotch tape. Now, researchers at the University of Alabama in Huntsville have determined that double-sided Scotch tape can improve triboelectric power generators. Triboelectric generation, of course, is nothing new. These energy harvesters take mechanical and thermal energy and turn them into tiny amounts of electricity. What’s new here is that PET plastic, aluminum, and double-sided tape can make an inexpensive generator that works well.

Keep in mind we are talking about little bits of power. In the best scenario with the device stimulated at 20 Hz, the generator peaked at 21.2 mW. That was better than some designs that only got to 7.6 mW in the same configuration.

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The PalmPilot Returns, This Time In Your Browser

December 4, 2022 by 31 Comments

The PalmPilot doesn’t seem to get much retrocomputing love, but maybe it should. After all, it might not have been the very first handheld, but it was probably the most successful, and that ultimately led to the era of the smartphone. Whether you miss your old Palm applications, or never got to experience them the first time around, fear not. You can now relive them in all their glory in your browser thanks to the Internet Archive project.

There are over 500 applications and games all running in a browser-based emulator. Some of the programs don’t seem to work well, and some don’t make sense in the context of a virtual environment. But many work fine, and if you want the classic apps, just open up anything and press the home button. If you want a review of the Palm IIIe PDA from 1999, check out [VWestlife’s] video, below.

The Grafitti handwriting recognition system was state-of-the-art for the day. The key was the system could more easily recognize printing if it were mostly single strokes that always worked the same way. For example, the “A” had no crossbar and the “F” was missing the bottom horizontal line. As much as possible, you make letters with a single stroke and there was only one way to form each letter. Good times!

What was high tech back then you can now build out of spare parts. If you happen to have a Palm, you might consider giving it a much-needed backlight.

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Better Coding Through Sketching

December 3, 2022 by 25 Comments

Back in the late 1970s and early 1980s, engineering students would take a few semesters of drafting and there would usually be a week or two of “computer-aided drafting.” In those days, that meant punching cards that said RECTANGLE 20,30 or something like that and getting the results on a plotter. Then we moved on to graphical  CAD packages, but lately, some have gone back to describing rather than drawing complex designs. Cornell University researchers are trying to provide the same options for coding. They’ve built a Juypter notebook extension called Notate that allows you to sketch and handwrite parts of programs that interact with traditional computer code. You can see a video about the work below.

The example shows quantum computing, but the idea could be applied to anything. The example has sketches that generate quantum circuits. Naturally, there is machine learning involved.

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Car Batteries: More Than Just Wet Lead

December 1, 2022 by 47 Comments

Working on car electrical systems used to be easy. The battery simply provided power for the car’s starter motor when starting or to run the small number of accessories when the engine wasn’t running. The rest of the time, the alternator charged the battery and provided power for the rest of the vehicle and the ignition system. While very early cars didn’t have batteries, and some old cars had 6 V positive ground systems, most of us have lived our entire lives where car batteries come in several sizes (controlled by Battery Council International) and cars have a 12 V, negative ground system.

Times have changed. Cars don’t have distributors anymore, they have computers. They also have lots of gadgets from GPS to backup cameras and cellphone chargers. Batteries have had to get beefier and the modern trend is to also require less maintenance So, today, you’ll find that there isn’t just one kind of car battery. But how do these other batteries work and what was wrong with the good old lead acid wet cell?

For the purposes of this post, I’m not talking about electric car batteries which is a whole different topic — and most of them have a regular car battery, too. Continue reading “Car Batteries: More Than Just Wet Lead” →