Materials For Self Learners

August 11, 2021 by Chris Lott 13 Comments

[João Nuno Carvalho] is a passionate learner. Software engineer by day, he studies all different branches of science and engineering in his spare time. He has organized an impressive list of study / reference materials on a wide variety of subjects that interest him, from aeronautical engineering to quantum mechanics and dozens more in between. In fact, his study lists themselves became so numerous that he collected them into a list of lists, which can be found here on his GitHub repository. These include categories on “How to learn…”

Modern Electronics
Modern Linux
Modern Embedded Systems
Mathematics from the ground up
Physics from the ground up
Modern Compressive Sensing
Modern [C, C++, Rust, Python]
Modern Machine Learning
Modern Aeronautics and Astronautics
Guitar on a budget

Another interesting thing we found in his repo was a list of common electrical components. If you can’t remember off the top of your head the part number of common 100 V PNP bipolar transistor, [João]’s list will point you towards a BD136.

It’s quite an impressive list of resources, and we can’t help but wonder how large [Joã0]’s personal library is if it contains even half of the materials from these lists. Check these out if you want to brush up on a topic — they include not only text books and reference volumes, but forums, blogs, YouTube links, etc. On the topic of learning, we wrote a piece back in 2017 on how learning differs between hobbyists and students. Do you have a favorite list-of-lists that you turn to when you want to brush up or learn about a new subject? Let us know in the comments below.

Everything You Always Wanted To Know About Radioactive Lenses

August 7, 2021 by Al Williams 45 Comments

We think of radioactive material as something buried away in bunkers with bombs, power plants, and maybe some exotic medical equipment. But turns out, there are little bits of radiation in the water, our soil, bananas, granite countertops, smoke detectors, and even some camera lenses. Camera lenses? A few decades ago, camera companies added rare elements like thorium to their glass to change the optical properties in desirable ways. The downside? Well, it made the lenses somewhat radioactive. A post by [lenslegend] explains it all.

Exotic elements such as Thorium, Lanthanum and Zirconium are added to glass mixtures to create the high refractive indexes necessary in sophisticated lens designs. Selection of premium quantities of glass from the large glass pots, stringent spectrophotometric tests after stress and strain checks provide the valuable raw glass for ultimate use in lens elements.
—Konica Hexanon Lens Guide, Konica Camera Company, 1972

According to [lenslegend] the practice started in 1945 with Kodak. However, by the 1980s, consumer distaste for radioactive things and concern for factory workers ended the production of hot camera lenses.

Continue reading “Everything You Always Wanted To Know About Radioactive Lenses” →

Magnus-Effect RC Aircraft Is A Lot Harder Than It Looks

August 5, 2021 by Danie Conradie 13 Comments

Conventional airfoil wings have come out on top for getting flying machines airborne over the last century, but there were a few other interesting designs that have come and gone. One of these is the Magnus effect plane, which makes use of the lift produced by a spinning cylinder. [James Whomsley] from [Project Air] decided to build one as a side project, but it ended up being a lot more challenging than what he initially suspected. (Video, embedded below.)

The Magnus effect achieved a bit of viral fame a few years when [How Ridiculous] dropped a basketball down a dam wall with some backspin. [James] T-shaped Magnus effect plane has a pair of spinning cylinders at the top to create lift, driven by a brushless motor using a belt. A second brushless motor with a propeller is on the center carbon fiber tube provides forward thrust, and a rudder provides yaw control. The battery is attached to the bottom of the tub for stability.

The very first flight looked very promising, but [James] quickly ran into a series of problems related to center of gravity, power, pitch control, and drag. After iterations of the build-crash-rebuild cycle, he ended up with larger motors and rudder, shorter “wings”, and a higher thrust motor position. This resulted in a craft still only marginally controllable, but stayed in the air for quite a while. Since the intention was never to turn it into a long-term project, James] called it a success to avoid more yak shaving, and continue work on his airboat and rocketplane.

If you are interested in building one of your own, he put all the findings of his experimentation in a short report. For more inspiration, check out the other Magnus effect plane we covered that used KFC buckets for the wings.

Continue reading “Magnus-Effect RC Aircraft Is A Lot Harder Than It Looks” →

Working LEGO Space Computers Are A Chip Off The Old Block

August 4, 2021 by Kristina Panos No comments

We all have our favorite classic LEGO bricks, and wouldn’t be surprised if one or more of the various space computers showed up on pretty much everyone’s list. [dyoramic] loves them so much that they built two different working versions that do different things.

The first one is about six times the size of the original brick. Inside the 3D printed case is an ESP32 and a 1.5″ OLED display. [dyoramic] wired up the top six buttons as inputs and the rest are just for looks. The screen defaults to the classic white cross on green that just sits there looking legit. But start pushing buttons and you’ll find other modes — the cross becomes a radar screen in one, the computer spits out space facts in another, there’s a falling bricks game, and finally, a time and date screen.

The second LEGO space computer build is even bigger — both were designed around the size of their screens. It has a Raspi 4 and shows a dashboard with the weather, time, date, latest xkcd, and a few cryptocurrency prices. [dyoramic] has an even bigger version in the works that will use a 720 x 720 screen and a handful of brown key switches as inputs. We can’t wait to see that one! For now, check out the build and demo of the first two after the break.

What can’t you do with LEGO? It feels like we’ve seen it all, from cameras to microscopes to continuously variable transmissions. Wouldn’t you love to drive one of those around the block?

Continue reading “Working LEGO Space Computers Are A Chip Off The Old Block” →

EXPS/2 Keyboard Adapter Translates PS/2 And USB To MSX

August 2, 2021 by Kristina Panos 9 Comments

Say what you will about suitcase computers, but at least most of them still have their keyboards with them. [danjovic] has this vintage Brazilian computer from the 1980s called a Gradiente Expert. These were MSX machines with Z80 chips that ran BASIC, DOS, and CP/M, and they looked like state-of-the-art dual-deck stereo systems. You can still find them pretty easily, but sadly, most of them have lost their rad mechanical keyboard with its giant arrow keys and proprietary connector.

If you now want to get one of these awesome pieces of computing history and would like to be able to talk to it, [danjovic] has you covered with the open-source EXPS/2 keyboard adapter. It will allow you to connect either a PS/2 keyboard or a USB keyboard in fallback mode to the Expert using an ATMega328P and a bespoke DIN-13 to DB-13 cable. As it turns out, there’s a wealth of information on MSX keyboard matrices out there.

How much do you know about the USB keyboard interface? If you want a warehouse of information delivered to your brain in the most pleasant way possible, go watch [Ben Eater] break it down with pen and paper.

Living The Dream: New PCB For A Dirt-Cheap Calculator Watch

August 1, 2021 by Kristina Panos 6 Comments

Well, this hack has us tickled pink. We love the idea of buying some really cheap piece of technology and doing something amazing with it, and this is a textbook example of that. [davedarko] found the cutest little calculator watch on Ali Express and is working on making a new PCB for it. The plan is to use an ARM processor and Arduino and add a few extras like 24-hour mode and a pink (or potentially RGB) backlight. The new brain will be an ATSAML22G18A, which has an on-board LCD controller and exactly one I/O pin to spare without charlieplexing the buttons.

One of [davedarko]’s primary goals is to keep the LCD and figure out how to talk to it. The first order of business was reverse engineering the watch’s LCD controller by sussing out the secrets from beneath the black blob of epoxy. This was an eye-opening experience as [davedarko] had never worked directly with LCDs before. A strange reading made him bust out the oscilloscope. Long-ish and informative story short, [davedarko] found out that it uses a bias of 1/2 for generating the wave necessary to multiplex the segments and keep the signal alternating. This is definitely one to watch!

We love timepieces around here and have seen all kinds of hacks, especially on Casio watches. Want dark mode? Done. Enable the hidden countdown timer? We’ve got that, too. And have you ever wondered just how water-resistant the F91W is?

Step ‘n Snack Fanny Pack Motivates With M&Ms

July 30, 2021 by Kristina Panos 5 Comments

[Sam March] has made a lot of different kinds of things, many of which have appeared on these very pages. Nowadays he wants to get the viewers more involved in his projects, so he started doing a monthly collaboration with YT viewers. Basically, he gives a prompt, and people comment with their wild and crazy ideas on the topic. Whoever has the winning idea gets the finished build. The maiden prompt was ‘fanny pack’, and you can check out the result in the build video (embedded below).

Someone suggested a Reese’s cup-dispensing fanny pack that gives you one cup for every 10,000 steps you take. We like what [Sam] did with that idea, because it’s way more practical — M&Ms are the original travel candy, and this way, you get to eat chocolate way more often. Depending on your sweet tooth, Reese’s Pieces would be a good compromise.

[Sam] figured out that the average human burns one calorie for every 25 steps, and that the average plain M&M is worth four calories, so he built a fanny pack with a step counter that dispenses one M&M for every 100 steps taken using a tiny auger. It’s calorie-neutrality!

You might be wondering if [Sam] made the fanny pack, too, or used something store-bought. The answer is neither: at some point in the build process, a company graciously offered to make a fanny pack with a special compartment in the bottom for the M&M dispenser. If you want to build one of these for yourself, you can get the CAD file for the milled base, the screw, the hopper, and the lid plus the code and also the gerbers on GitHub. We see a place for the sewing pattern, but as of now, the folder is empty. Be sure to check out the build and demo video after the break as [Sam] hits the town in a screaming set of neon workout wear to test the dispenser.

Most of the M&M-based projects we see around here are designed to sort by color. Here’s one that searches for the holy grail — peanut M&Ms that didn’t get a peanut. Continue reading “Step ‘n Snack Fanny Pack Motivates With M&Ms” →