TouchPad

20 Articles

Crabapplepad Folding Keyboard Is Actually Pretty Sweet

October 13, 2023 by 10 Comments

[Sergei Silnov] was quite attached to the Microsoft Natural Ergonomic 4000 keyboard, an updated version of their Natural keyboard that brought so many into the split fold. But once [Sergei] started writing notes in coffee shops, it was time for something portable.

The trouble with many portable keyboards, especially folding ones, is that they’re not often comfortable to type on. However, the Crabapplepad, a sleek, elegant offering, looks as though it begs to differ.

[Sergei] truly thought of everything and packed it into this 2cm thick wonder. There’s a little kickstand to hold your phone, or you can just throw an Apple trackpad between the halves and it magnetically attaches. Inside there’s a Seeed Studio XIAO nRF52840, and the switches are the extremely thin and hard-to-find Kailh PG1425 X, a sweet-looking scissor switch.

The only problem with X-switches is that there is only one type of keycap for them at the moment, and there aren’t any homing bums for F and J. To get around this, [Sergei] designed some 3D-printed frames to go around the keycaps and make them more distinct. Yes, this beauty it is open source, so go forth and be comfortable in absolute style. Don’t forget to check out the demo after the break.

To be honest, there once was a pretty good folding keyboard — the Palm Portable. Don’t worry; someone made a Bluetooth adapter for them.

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Turning The Back Of Your Phone Into A Touchpad

July 21, 2022 by 28 Comments

Smartphones use big touchscreens on the front as a useful tactile interface. However, our hands naturally wrap around the back of the phone, too. This area is underutilized as an interface, but the designers of BackTrack found a way to change that.

Touches on the 2D rear matrix are translated into a pair of touches on the linear line of pads on the front screen. This can then be reconstructed into the touch location on the rear touchpad.

The idea is simple. The project video notes that  conductive tape can be placed on a multitouch touchscreen, allowing touches to be read at a remote location. Taking this concept further, BackTrack works by creating a 2D matrix on the back of the phone, and connecting this matrix to a series of pads in a row on the front touchscreen. Then, touches on the back touchpad can be read by the existing touchscreen on the front screen. Continue reading “Turning The Back Of Your Phone Into A Touchpad” →

Making Your Own Touchpad With PWM And Rust

November 16, 2021 by 9 Comments

The modern touchpads are incredible feats of engineering, with everything from complex signal processing for noise and tremendous economies of scale driving prices low. So [Kevin] decided to see if he could make his own touchpad. Partially out of curiosity of what makes one touchpad better than another, but also because he was curious if he could. Using an STM32 and a custom PCB, he was off to the races in an incredibly cost-effective way.

After writing some quick firmware in Rust, he was reporting the values read by the PWM channels. Using python, he could get a good idea of the raw values that were being written over USB and visualized. So rather than implement filtering in hardware or firmware, he elected to do the filtering and processing on the host computer side in Python. We suspect this gave him much shorter iteration cycles.

If you like the idea of making your own touchpad but perhaps are dreaming a little bigger, why not make a tablecloth-sized touchpad?

Control A Motor With A Touchpad

June 10, 2020 by 11 Comments

There are a surprising wealth of parts inside of old laptops that can be easily scavenged, but often these proprietary tidbits of electronics will need a substantial amount of work to make them useful again. Obviously things such as hard drives and memory can easily be used again, but it’s also possible to get things like screens or batteries to work with other devices with some effort. Now, there’s also a way to reuse the trackpad as well.

This build uses a PS/2 touchpad with a Synaptics chip in it, which integrates pretty smoothly with an Arduino after a few pins on the touchpad are soldered to. Most of the work is done on the touchpad’s built in chip, so once the Arduino receives the input from the touchpad it’s free to do virtually anything with it. In this case, [Kushagra] used it to operate a stepper motor in a few different implementations.

If you have this type of touchpad lying around, all of the code and schematics to make it useful again are available on the project page. An old laptop in the parts bin is sure to have a lot of uses even after you take the screen off, but don’t forget that your old beige PS/2 mouse from 1995 is sure to have some uses like this as well.

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Joy-Con Mod Gives Nintendo Switch Touchpad Control

May 22, 2020 by 21 Comments

While Valve’s Steam Controller ultimately ended up being a commercial flop, most users agreed its use of touch-sensitive pads in place of traditional analog joysticks or digital directional buttons was at least a concept worth exploring. Those same touchpad aficionados will likely be very interested in this modification by [Matteo Pisani], which replaces the analog joystick on a Nintendo Switch Joy-Con with a capacitive touch sensor.

As [Matteo] explains in his detailed write-up, the initial inspiration for this project was to create a permanent solution to joystick fatigue and drifting issues. He reasoned that if he removed the physical joystick completely, there would be no way for it to fail in the future. We’re not sure how many people would have taken the concept this far, but you can’t argue with the logic.

The original joystick is a fairly straightforward device, comprised of two analog potentiometers and a digital button. It’s connected to the Joy-Con’s main PCB with a 0.5 mm pitch flexible cable, so the first step for [Matteo] was to spin up a breakout for the cable in KiCad to make the development process a bit easier.

The board design eventually evolved to hold an Arduino Pro Mini, a digital potentiometer, and a connector for the circular touchpad. The Arduino communicates with both devices over I2C, and translates the high resolution digital output of the touch controller into an analog signal within the expected ranges of the original joystick. [Matteo] says he still has to implement the stick’s digital push button, but thanks to an impressive 63 levels of pressure sensitivity on the pad, that shouldn’t be a problem.

Now that he knows the concept works, the next step for [Matteo] is to clean it up a bit. He’s already working on a much smaller PCB that should be able to fit inside the Joy-Con, and we’re very interested in seeing the final product.

We’ve seen several interesting Joy-Con hacks since the Switch hit the market, including a somewhat less intense joystick swap. Between the Joy-Con and the legendary Wii Remote, Nintendo certainly seems to have a knack for creating input devices that catch the imagination of gamers and tinkerers alike.

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Go Big Or Go Home: A Tablecloth Touchpad

May 23, 2017 by 10 Comments

Phone screens keep getting bigger. Computer screens keep getting bigger. Why not a large trackpad to use as a mouse? [MaddyMaxey] had that thought and with a few components and some sewing skills created a trackpad in a tablecloth.

The electronics in this project are right off the shelf. A Flora board for the brains and 4 capacitive touch boards. If you haven’t seen the Flora, it is a circular-shaped Arduino made for sewing into things. The real interesting part is the construction. If you haven’t worked with conductive fabric and thread, this will be a real eye-opener. [Maddy’s] blog has a lot of information about her explorations into merging fabric and electronics and also covers things like selecting conductive thread.

As an optional feature, [MaddyMaxey] added vibration motors that provide haptic feedback to her touchpad. We were hoping for a video, but there doesn’t seem to be one. The code is just the example program for the capacitive sensor boards, although you can see in a screenshot the additions for the haptic motors.

We’ve covered the Flora before, by the way. You could also make a ridiculously large touch surface using tomography, although the resolution isn’t quite good enough for mouse purposes.

Laptop Trackpads And MIDI Controllers

October 26, 2013 by 9 Comments

pads

A bunch of pads connected to a MIDI out port is as old an idea as the Akai MPC. creating a homebrew version is great, but [Scott] took his version one step further. He used old laptop trackpads to control note on and note off commands when the each pad is tapped, and also added MIDI CC values for the touch pressure and the x and y-axis position.

The trackpads were identical models, each having their own PS/2 output. A few ribbon cable to 8-pin header adapters were manufactured, and the entire ensemble encased in a wonderful maple and aluminum enclosure.

The electronics are based on an Arduino Mega with 16 clock and data points for each touchpad eating up 32 of the 54 available pins on the ‘duino. The PS/2 protocol is well documented, but running 16 separate PS/2 id most certainly not. [Scott] ended up writing his own asynchronous PS/2 communications library to get the latency of his midi device down to about 50ms.

It’s an amazing bit of kit and comparatively inexpensive, given that [Scott] now has a 16-channel Kaoss pad. Video of the device hooked up to a MicroKorg below.

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