Component Shelf Life: How To Use All That Old Junk

April 23, 2019 by Ted Yapo 31 Comments

There are two types of Hackaday readers: those that have a huge stock of parts they’ve collected over the years (in other words, an enormous pile of junk) and those that will have one a couple of decades from now. It’s easy to end up with a lot of stuff, especially items that you’re likely to use in more than one design; the price breakpoints at quantities of 10 or 100 of something can be pretty tempting, and having a personal stock definitely speeds the hacking process now that local parts shops have gone the way of the dinosaur. This isn’t a perfect solution, though, because some components do have shelf-lives, and will degrade in some way or another over time.

If your stash includes older electronic components, you may find that they haven’t aged well, but sometimes this can be fixed. Let’s have a look at shelf life of common parts, how it can be extended, and what you can do if they need a bit of rejuvenation.

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Need A Small Keyboard? Build Your Own!

April 23, 2019 by Brian Benchoff 72 Comments

If you want keyboards, we can get you keyboards. If you want a small keyboard, you might be out of luck. Unless you’re hacking Blackberry keyboards or futzing around with tiny tact switches, there’s no good solution to small, thin, customization keyboards. There’s one option though: silicone keyboards. No one’s done it yet, so I figured I might as well.

Unfortunately, there is no readily available information on the design, construction, or manufacture of custom silicone keypads. There is a little documentation out there, but every factory that does this seems to have copy and pasted the information from each other. Asking a company in China about how to do it is a game of Chinese Whispers. Despite this, I managed to build a custom silicone keypad, and now I’m sharing this information on how to do it with you.

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Add-Ons Go Electroluminescent

April 17, 2019 by Brian Benchoff 24 Comments

It’s that time of the year again, and once more we’re faced with the latest innovations in Badgelife, the movement to explore the artistic merits of electronics and manufacturing. This is an electroluminescent printed circuit board, and it’s some of the finest work we’ve seen. It’s also a Shitty Add-On that glows blue.

The process for applying an electroluminescent coating to printed circuit boards is, surprisingly, something we’ve covered before. Late last year, [Ben Krasnow] delved deep into a DIY EL display. The process is expensive, but all the products come from a company called Lumilor. The first step in this process is applying a thin conductive coating on a substrate with an airbrush. Since the entire idea of printed circuit boards is to have a layer of conductive material etched into any shape you want, the simple circuit board is the idea experimental platform for playing with EL displays. Traditionally, EL displays were made entirely with a silk screen process, like [Fran]’s ongoing attempt to recreate the Apollo DSKY display.

The electronics for this badge are simply a Microchip MIC4832 EL Driver, which converts the 3.something volts from the add-on header into 100 or so Volts AC at hundreds of Hz. This is a single-chip solution to driving EL displays, and the only other parts you need are an inductor, diode, and a few caps and resistors. An ATtiny85 can be used to blink the circuits, or, alternatively, you could copy [Ben]’s work and build a character EL display.

The process of applying an electroluminescent coating to a PCB does require a spray gun or airbrush, and the chemicals are a bit expensive. This, though, is pushing the boundaries of what can be done with artistic PCBs. It’s new applications of technology, simply as wearable electronics. It’s the best example of the possibilities of the medium and some of the best work that’s come out of the Badgelife scene.

What Can You Learn From An Eggbot?

April 17, 2019 by Elliot Williams 32 Comments

An eggbot is probably the easiest introduction to CNC machines that you could possibly hope for, at least in terms of the physical build. But at the same time, an eggbot can let you get your hands dirty with all of the concepts, firmware, and the toolchain that you’d need to take your CNC game to the next level, whatever that’s going to be. So if you’ve been wanting to make any kind of machine where stepper motors move, cut, trace, display, or simply whirl around, you can get a gentle introduction on the cheap with an eggbot.

Did we mention Easter? It’s apparently this weekend. Seasonal projects are the worst for the procrastinator. If you wait until the 31st to start working on your mega-awesome New Year’s Dropping Laser Ball-o-tron 3000, it’s not going to get done by midnight. Or so I’ve heard. And we’re certainly not helping by posting this tutorial so late in the season. Sorry about that. On the other hand, if you start now, you’ll have the world’s most fine-tuned eggbot for 2020. Procrastinate tomorrow!

I had two main goals with this project: getting it done quickly and getting it done easily. That was my best shot at getting it done at all. Secondary goals included making awesome designs, learning some new software toolchains, and doing the whole thing on the cheap. I succeeded on all counts, and that’s why I’m here encouraging you to build one for yourself.

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Picking The Right Sensors For Home Automation

April 16, 2019 by Maya Posch 22 Comments

Imagine that you’re starting a project where you need to measure temperature and humidity. That sounds easy in the abstract, but choosing a real device out of many involves digging into seemingly infinite details and trade-offs that come with them. If it’s a low-stakes monitoring project, picking the first sensor that comes to mind might suffice. But when the project aims to control an AC system in an office of temperature-sensitive coders, it pays to take a hard look at the source of all information: the sensor.

Continuing a previous article I would like to use that same BMaC project from that article as a way to illustrate how even a couple of greenhorns can figure out how to pick everything from environmental sensors to various actuators, integrating it into a coherent system that in the end actually does what it should.

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A Robust ESP8266 RFID Access Control System

April 15, 2019 by Tom Nardi 19 Comments

By now we’ve seen plenty of projects that use an ESP8266 as a form of rudimentary access control: tap a button on your smartphone, and the door to your apartment unlocks. With the power and flexibility of the ESP, it’s a very easy project to pull off with minimal additional hardware. But what about if you want to get a little more serious, and need to support many users?

Rather than reinvent the wheel, you might want to check out the extremely impressive ESP-RFID project. It’s still based on the ESP8266 we all know and love, but it combines the diminutive WiFi-enabled microcontroller with a nice custom PCB and some exceptionally slick software to create a very professional access control system without breaking the bank. As the name implies, the system is geared towards RFID authentication and supports readers such as the MFRC522, PN532 RFID, or RDM6300. Add in a stack of Mifare Classic 1KB cards, and your hackerspace is well on the way to getting a new door control system.

The official hardware for ESP-RFID can be purchased through Tindie with or without an installed ESP-12F module, but as it’s a fully open source project, you’re also free to build your own version if you’d like. In either event, the board allows you to easily connect the ESP up to your RFID reader of choice, as well as door sensors and of course the door locks themselves.

On the software side of things, ESP-RFID should be able to handle about 1000 unique users and their RFID cards before the relatively limited RAM and storage of the ESP catches up with it. But if you’ve got that many people coming and going in your hackerspace, it might be time to update your systems to begin with. Incidentally, the project makes no guarantees about the security of the ESP-RFID code, and says that the system shouldn’t be used for secure locations. That said, you can run ESP-RFID without an Internet connection to reduce your attack surface, at the cost of losing NTP time synchronization.

If you’re not managing a few hundred users and their RFID cards, one of the more simplistic ESP8266 door locks might be more your speed. We’ve also seen similar tricks pulled off with the Particle Photon, in case you’ve got one of those rattling around the parts bin.

Implementing Qi Inductive Charging Yourself

April 11, 2019 by Jenny List 21 Comments

Inductive charging is a technology that has promised a lot, but hasn’t quite delivered on the promise of never needing to plug in your phone again. The technology behind it is surprisingly simple though, and [Vinod.S] takes us through it all with an ATtiny13-based example.

An inductive charger has to be clever in its operation, for if it were to operate continuously it would soon have more in common with an inductive hob and thus become a fire risk, so it has to be sure that a compatible device is resting upon it before it tries to transmit power. It achieves this by periodically sending out a pulse of power intended to wake any devices in contact with it, and the device responds with a serial data stream encoded onto the device’s field by modifying the resonance of the receiver tuned circuit. This is done by a pair of MOSFETs under the control of the ATtiny in [Vinod]’s device, resulting in a functioning inductive power receiver built on a piece of prototyping board and sporting a buck converter capable of supplying 5 volts suitable to charge a phone. You can find the code on GitHub and see it in action below the break.

This tech has made an appearance here before a few times, such as when a Qi charger was integrated into a Chromebook.

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