Adding Analog Touch To (Nearly) Any Mechanical Keyboard

September 26, 2018 by Brian Benchoff 37 Comments

The new hotness for DIY electronics is mechanical keyboards, and over the past few years we’ve seen some amazing innovations. This one is something different. It adds an analog sensor to nearly any mechanical key switch, does it with a minimal number of parts, and doesn’t require any modification of the switch itself. It’s a reddit thread and imgur post, but the idea is just so good we can overlook the documentation on this one.

The key development behind this type of sensor is realizing that nearly every mechanical keyswitch (Cherry MX, Kalth, Gateron) has a spring in the bottom. A spring is just a coil of wire, and an inductor is just a coil of wire, too. By putting a spiral trace on the PCB of a mechanical keyboard underneath the keyswitch, you can sense the inductance of this spring. This does require a little bit of additional hardware, in this case an LDC1614 inductance to digital converter, but this is an I2C-readable part that can, theoretically, be integrated rather easily with any mechanical keyboard PCB and firmware.

The downside to using the LDC1614 is that sampling is somewhat time-limited, with four channels or individual keys being polled at 500 Hz. This isn’t a problem if the use-case is adding analog to your WASD keys, but it may become a problem for an entire keyboard. Additionally, the LDC1614 is a slightly expensive part, at about $2 USD in quantity 1000. A fully analog keyboard using this technique is going to be pricey.

Right now, the proof-of-concept for this analog mechanical keyswitch is just a 0.1 mm flexible PCB that is shoehorned inbetween a Cherry MX red and a (normal) mechanical keyboard PCB. The next step in the development will be a 2×4 keypad with analog sensors, and opening up the hardware and firmware examples up under a GPL license.

DIY Puff-Suck Interface Aims For Faster Text Input

September 25, 2018 by Donald Papp 9 Comments

Puff and Suck (or Sip and Puff) systems allow people with little to no arm mobility to more easily interact with computers by using a straw-like unit as an input device. [Ana] tells us that the usual way these devices are used to input text involves a screen-based keyboard; a cursor is moved to a letter using some method (joystick, mouse emulator, buttons, or eye tracking) and that letter is selected with a sip or puff into a tube.

[Ana] saw such systems as effective and intuitive to use, but also limited in speed because there’s only so fast that one can select letters one at a time. That led to trying a new method; one that requires a bit more work on the user’s part, but the reward is faster text entry. The Puff-Suck Interface for Fast Text Input turns a hollow plastic disk and a rubber diaphragm into bipolar pressure switch, able to detect three states: suck, puff, and idle. The unit works by having an IR emitter and receiver pair on each side of a diaphragm (one half of which is shown in the image above). When air is blown into or sucked out of the unit, the diaphragm moves and physically blocks one or the other emitter-receiver pair. The resulting signals are interpreted by an attached Arduino.

How does this enable faster text input? By throwing out the usual “screen keyboard” interface and using Morse code, with puffs as dots and sucks as dashes. The project then acts as a kind of Morse code keyboard. It does require skill on the user’s part, but the reward is much faster text entry. The idea got selected as a finalist in the Human-Computer Interface Challenge portion of the 2018 Hackaday Prize!

Morse code may seem like a strange throwback to some, but not only does the bipolar nature of [Ana]’s puff-suck switch closely resemble that of Morse code input paddles, it’s also easy to learn. Morse code is far from dead; we have pages of projects and news showing its involvement in everything from whimsical projects to solving serious communication needs.

Send Smooches Over Skype With The Kiss Interface

September 23, 2018 by Donald Papp 14 Comments

This project of [Nathan]’s certainly has a playful straightforwardness about it. His Skype ‘Kiss’ Interface has a simple job: to try to create a more intuitive way to express affection within the limits of using Skype. It all came about from a long distance relationship for which the chat program was the main means of communicating. Seeking a more intuitive and personal means of expressing some basic affection, [Nathan] created a capacitive touch sensor that, when touched with the lips, sends the key combination for either a kissy face emoji or the red lips emoji, depending on the duration.

Capacitive touch sensing allows for triggering the sensor without actually physically touching one’s lips to the electrodes, which [Nathan] did by putting a clear plastic layer over the PCB traces. His board uses an STM32 microcontroller with software handling the USB HID and STM’s TSC (Touch Sensing Controller) functionality. As a result, the board has few components and a simple interface, which was in keeping with the goal of rejecting feature creep and focusing on a simple task.

Clearly the unit works; but how well does it actually fulfill its intended purpose? We don’t know that yet, but we do know that [Nathan] seems to have everything he needs in order to find out. Either way, it’s a fun project that definitely fits the spirit of the Human-Computer Interface Challenge of The Hackaday Prize.

Make An Electric Skateboard For Your Cat

September 21, 2018 by Richard Baguley 10 Comments

Have you ever looked at your cat and thought “You know, my kitten really needs an electric skateboard!” Probably not, but this seems to have happened to [Kim Pimmel] while looking at his cat MIDI, so he decided to build one. This process involved building a simple, low powered skateboard with a Feather mainboard and motor controller combined with a laser-cut switch mechanism. When [Kim] puts a treat into the mechanism, the cat pulls the switch and the skateboard moves forward, moving into a brave new e-skateboarding feline future. MIDI looks somewhat unimpressed by this whole business, but I suspect that as long as the treats keep coming, he will be happy to keep on truckin’. Now, if he can just figure out how to persuade the cat to ollie, we will be really getting somewhere.

Feline tomfoolery seems to be a regular pastime here on these pages, and more than just a quest for easy moggy-driven clickbait. A lot of cat feeders and cat finders abound, but this project isn’t the only cat-operated one. Our readers’ pets can probably spot an Arduino a mile away by now.

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C64 Keyboard Helps Keep The Memory Alive

September 20, 2018 by Tom Nardi 11 Comments

To say that the Commodore 64 was an important milestone in the history of personal computing is probably a bit of an understatement. For a decent chunk of the 1980s, it was the home computer, with some estimates putting the total number of them sold as high as 17 million. For hackers of a certain age, there’s a fairly good chance that the C64 holds a special spot in their childhood; perhaps even setting them on a trajectory they followed for the rest of their lives.

At the risk of showing his age, [Clicky Steve] writes in to tell us about the important role the C64 played in his childhood. He received it as a gift on his fifth birthday from his parents, and fondly remembers the hours he and his grandfather spent with a mail order book learning how to program it. He credits these memories with getting him interested in technology and electronic music. In an effort to keep himself connected to those early memories, he decided to build a modern keyboard with C64 keycaps.

As you might expect, the process started with [Steve] harvesting the caps from a real Commodore, in fact, the very same computer he received as a child. While the purists might shed a tear that the original machine was sacrificed to build this new keyboard, he does note that his C64 had seen better days.

Of course, you can’t just pull the caps off of C64 and stick them on a modern keyboard. [Steve] found the STLs for a 3D printable C64 to Cherry MX adapter on GitHub, and had 80 of them professionally printed as he doesn’t have access to an SLS printer. He reports the design works well, but that non-destructively removing the adapters from the caps once they are pressed into place probably isn’t going to happen; something to keep in mind for others who might be considering sacrificing their personal C64 for the project.

[Steve] installed the caps on a Preonic mechanical keyboard, which worked out fairly well, though he had to get creative with the layout as the C64 caps didn’t really lend themselves to the keyboard’s ortholinear layout. He does mention that switches a bit heavier than the Cherry MX Whites he selected would probably be ideal, but overall he’s extremely happy with his functional tribute to his grandfather.

If you’re more of a purist, you can always adapt the C64 keyboard directly to USB. Or go in the complete opposite direction and put a Raspberry Pi into a C64 carcass.

This Keyboard And Mouse Also Gives You A Workout

September 20, 2018 by Brian Benchoff 2 Comments

The Ergonomic Handheld Mouse / Keyboard Alternative from [Shervin Emami] is an all-in-one solution for your keyboarding and cursor moving needs.

The core of this build is a ‘grip-strengthening’ device that’s sold to guitarists. While the actual benefit of these devices for guitarists is questionable — there are a few anecdotes any music teacher will tell you about classical pianists ruining their hands with similar devices — the device itself can be converted into a fantastic chording keyboard. All you really need for a full-functioned keyboard is a few buttons in a rugged shell, and this ‘grip strengthener’ has that going in spades.

Underneath the plungers for each button [Shervin] installed a magnet and a magnetic sensor, meaning these buttons are analog, and shouldn’t wear out ever. With just a little bit of code on a Tiny BLE board these analog sensors can become a keyboard, a quadcopter controller, an interface for your VR setup, or anything else that can be controlled with a bunch of buttons.

Not to outdo himself, [Shervin] also managed to add some cursor control functionality to this build. This is done via the IMU onboard the Tiny BLE board, and by all accounts it works great. You can check out a video of this build pretending it’s both a keyboard and a mouse below.

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DIY Switches For People Who Can’t Push Switches

September 10, 2018 by Donald Papp 3 Comments

An outstanding number of things most people take for granted present enormous hurdles for people with physical disabilities, including interaction with computers and other digital resources. Assistive technologies such as adaptive switches allow users who cannot use conventional buttons or other input devices to interact with digital devices, and while there are commercial offerings there is still plenty of room for projects like [Cassio Batista]’s DIY Low-cost Assistive Technology Switches.

[Cassio]’s project focuses on non-contact switches, such as proximity and puff-based activations. These are economical, DIY options aimed at improving accessibility for people who are unable to physically push even specialized switches. There are existing products in this space, but cost can be a barrier and DIY options that use familiar interfaces greatly improves accessibility.

Assistive technologies that give people the tools they need to have more control over their own lives in a positive, healthy way is one of the more vibrant and positive areas of open hardware development, and it’s not always clear where the challenges lie when creating solutions. An example of this is the winner of the 2015 Hackaday Prize, the Eyedrivomatic, which allows one to interface the steering of an electric wheelchair to a gaze tracking system while permanently altering neither device; a necessity because users often do not own their hardware.