Steve showing a circuit built with spintronics blocks

Electronics Explained With Mechanical Devices

It can be surprisingly hard to find decent analogies when you’re teaching electronics basics. The water flow analogy, for instance, is decent for explaining Ohm’s law, but it breaks down pretty soon thereafter.

Hydraulics aren’t as easy to set up when you want an educational toykit for your child to play with, which leaves them firmly in the thought experiment area. [Steve Mould] shows us a different take – the experimentation kit called Spintronics, which goes the mechanical way, using chains, gears, springs and to simulate the flow of current and the effect of potential differences.

Through different mechanical linkages between gears and internal constructs, you can implement batteries, capacitors, diodes, inductors, resistors, switches, transistors, and the like. The mechanical analogy is surprisingly complete. [Steve] starts by going through the ways those building blocks are turned into mechanical-gear-based elements. He then builds one circuit after another in quick succession, demonstrating just how well it maps to the day-to-day electronic concepts. Some of the examples are oscillators, high-pass filters, and amplifiers. [Steve] even manages to build a full-bridge rectifier!

In the end, he also builds a flip-flop and an XOR gate – just in case you were wondering whether you could theoretically build a computer out of these. Such a mechanical approach makes for a surprisingly complete and endearing analogy when teaching electronics, and an open-source 3D printable take on the concept would be a joy to witness.

Looking for something you could gift to a young aspiring mind? You don’t have to go store-bought – there are some impressive hackers who build educational gadgets, for you to learn from.

Fritzing diagram of connections between the Wemos D1 board, the TP4056 board, the pushbutton and the LiIon battery

Battery-Powered ESP8266 Sensor? Never Been Simpler

Say, you’re starting your electronics journey with a few projects in mind. You have an ESP8266 board like the Wemos D1, a Li-Ion battery, you want to build a small battery-powered sensor that wakes up every few minutes to do something, and you don’t want to delve into hardware too much for now. Well then, does [Mads Chr. Olesen] have a tutorial for you! Here, you’ll learn the quick and easy way to get your sensor up and running, learn a few tricks for doing sleep Arduino environment, and even calculate how long your specific battery could last. Continue reading “Battery-Powered ESP8266 Sensor? Never Been Simpler”

A closeup picture showing the jagged edge of the cut

Debugging Laser Cut Wobble, The Scientific Way

[PWalsh] was using his lasercutter to cut acrylic, expecting the cuts to have a pleasantly smooth edge. Alas, the edges turned out to be wobbly and sandpaper-like, not smooth in the slightnest. Bummer! Internet suggested a stepper motor swap, but not much in the way of insights – and that would’ve been a royal pain for sure. How would you approach debugging such a problem? Well, [PWalsh] didn’t want to swap crucial components willy-nilly, going the scientific way instead, and breaks it down for us.

Having compiled an extensive list of possible places to look for a fault in, he started going through fundamental assumptions. Do other lasercutters experience this issue? No, even the cheap ones can cut things properly. Is it water level causing intermittent cooling? Nope, not that. Is it the stepping settings? Tweaked, not that. Laser pulsing frequency? No dice. Continue reading “Debugging Laser Cut Wobble, The Scientific Way”

The Sweetest Glue In The World

Perhaps we’re not alone in having a penchant for gummy sweets, but we have to admit to never following the train of thought shared by [Lost Art Press]. Upon finding that a hide glue ingredient was raw gelatin obtained from a confectionery company, they stored away the knowledge and eventually tried making some glue using Haribo Goldbears from a gas station.

Melting the anthropomorphised sweets in a pot with a little water produced a thin glue, which was tried on a couple of bits of wood. The test joint duly stuck together, and after a few weeks for it to set it was time to test it. Simply hitting it with a hammer caused the wood to fracture, but using more traditional hide glue dissolving techniques with water or alcohol gave the expected result of parting it.

So a pretty usable hide glue for woodworking can be made using gummy sweets. We think it’s pretty cool, but perhaps given how easy it is to buy either the real thing or a PVA-based alternative, that this is one for the MacGyver file. Should you ever find yourself stranded in a gas station unable to save the world for want of a bit of glue then now you have the crucial bit of knowledge. Until then, leave out Haribo Goldbears alone!

Thanks [Aaron Tagliaboschi] for the tip!

NTC Thermistor To ThingSpeak Meter Makes A Great IoT Starter Project

There are a lot of IoT solutions and frameworks out there, and [Davide] demonstrates how to make a simple data logging and tracking application with his ESP8266-to-ThingSpeak project, which reads up to four NTC (negative temperature coefficient) thermistors and sends the data to ThinkSpeak over WiFi.

IoT can be a pretty deep rabbit hole, so if you’re looking for a simple project to demonstrate the working parts and provide a starting point, the project’s GitHub repository might help you get started. We’ve also seen ThingSpeak used to track toilet paper sheet usage, which is a nice demonstration of how to interface to a physical object with moving parts.

On the other hand, if you find reading NTC thermistors to be the more interesting part, you’re in luck because [Davide] has more information about that along with a modified ESP8266 Arduino library. Watch a tour of his temperature logging hardware in action in the video, embedded below.

Continue reading “NTC Thermistor To ThingSpeak Meter Makes A Great IoT Starter Project”

All About USB-C: Connector Mechanics

There’s two cases when hackers have to think about USB-C connector mechanics. The first is when a USB-C connector physically breaks, and the second is when we need to put a connector on our own board. Let’s go through both of them.

Clean That Connector

What if a socket on your phone or laptop fails? First off, it could be due to dust or debris. There’s swabs you can buy to clean a USB-C connector; perhaps adding some isopropyl alcohol or other cleaning-suitable liquids, you can get to a “good enough” state. You can also reflow pins on your connector, equipped with hot air or a sharp soldering iron tip, as well as some flux – when it comes to mechanical failures, this tends to remedy them, even for a short period of time.

How could a connector fail, exactly? Well, one of the pins could break off inside the plastic, or just get too dirty to make contact. Consider a device with a USB-C charging and data socket, with USB 2.0 but without high-speed pairs – which is to say, sadly, the majority of the phones out there. Try plugging it into a USB-A charger using a USB-A to USB-C cable. Does it charge, even if slowly? Then, your VBUS pins are okay.

Plug it into a Type-C charger using a Type-C cable, and now the CC pins are involved. Does it charge in both orientations? Then both of your CC pins are okay. Does it charge in only one orientation? One of the CC pins has to be busted. Then, you can check USB 2.0 pins, used for data transfer and legacy charging. Plug the phone into a computer using a USB-A to USB-C cable. Does it enumerate as a device? Does it enumerate in both orientations? If not, you might want to clean D- and D+ pins specifically, maybe even both sets. Continue reading “All About USB-C: Connector Mechanics”

Fixing (And Improving!) An Annoying Apartment Entry System

[Zak]’s two-floor apartment has a typical door entry control system, but the setup is less than ideally convenient. The wall-mounted telephone-like intercom is downstairs, but [Zak] is usually upstairs. What’s an enterprising hacker to do? Obviously the most elegant solution is to simply do without visitors in the first place, but [Zak] opted for a more full-featured solution to the problem.

The layout of the typical wall-mounted door intercom is less than ideal.

He fixed things with a custom ESP8285-based board that, with the help of opto-isolation, allows him to detect visitors and grant entry without having to be physically present at the wall-mounted intercom. It’s even integrated into Telegram, and has a few neat new features. Let’s take a look.

The first interesting bit is how [Zak] rolled his own opto-isolation. The door entry system uses 14 VAC and is frankly — electromagnetically-speaking — a very noisy device. Attaching GPIO pins directly to this system from the ESP board for interfacing is not an option. The solution in situations like this is to use opto-isolation, so that interfaced devices can be electrically isolated from one another.

Rather than use off-the-shelf options, [Zak] opted to keep things small and economical by rolling his own solution using side-mounted IR LEDs on the small interface PCB. LEDs can also act as photodiodes, so by pointing two LEDs directly at one another and driving one LED from the door control system and measuring the small amount of resulting current on the other LED, [Zak] can detect states without having to directly connect a GPIO pin.

Continue reading “Fixing (And Improving!) An Annoying Apartment Entry System”