The board in question, with a Pi Pico soldered on, with old PCBs for macropads being used as captouch electrodes

Give Your Pi Pico Captouch Inputs For All Your Music Needs

March 31, 2024 by Arya Voronova 11 Comments

Unlike many modern microcontrollers, RP2040 doesn’t come with a native capacitive touch peripheral. This doesn’t mean you can’t do it – the usual software-driven way works wonderfully, and only requires an external pullup resistor! In case you wanted a demonstration or you have a capacitive touch project in mind, this lighthearted video by [Jeremy Cook] is a must watch, and he’s got a healthy amount of resources for you in store, too!

In this video, [Jeremy] presents you with a KiCad schematic and an PCB design you can use to quickly add whole 23 capacitive touch sensing inputs to a Pi Pico! The board is flexible mechanically, easy to assemble as [Jeremy] demonstrates, and all the pins involved can still be used as regular GPIOs if you’d like. Plus, it’s fully open-source, can easily be assembled on your own, and available on Tindie too!

Of course, such a board doesn’t get created for no reason – [Jeremy] has a healthy amount of musical creations and nifty ideas to show off. We quite liked the trick of using old PCBs as capacitive touch sensing, using copper fills as electrodes – which has helped create an amusing “macropad of macropads”, and, there’s quite a bit more to see.

If capacitive touch projects ever struck a chord with you and you enjoy music-related hacking, [Jeremy]’s got a whole YouTube channel you ought to check out. Oh, and if one of the musical projects in the video caught your eye, it might just be the one we’ve featured previously! Continue reading “Give Your Pi Pico Captouch Inputs For All Your Music Needs” →

Thumbs Up To This Pico MIDI Kalimba

March 6, 2024 by Kristina Panos 8 Comments

The kalimba, or thumb piano, is an easy way to make some music even if you have next to no idea what you’re doing. The only real downside is that they are limited to the twinkly sounds of metal tines being plucked by thumbs.

[Jeremy Cook] broke the sonic possibilities wide open by converting a couple of kalimbas into capacitive-touch MIDI instruments using the Raspberry Pi Pico. He started with a small one that is curiously made of solid wood. Usually these instruments are at least partially hollow to allow air to resonate inside the body.

After soldering up all the 1 MΩ resistors necessary to utilize the capacitive touch capabilities of the Pico, [Jeremy] found it a bit difficult to play individual notes on such a small instrument, so he made version two out of a much larger specimen.

This time, [Jeremy] cooked up a custom PCB which he is calling the Pico Touch 2, which adds the necessary resistors at the SMD level for capacitive touch sensing and in turn cleans up the wiring a bit. Be sure to check it out in action after the break.

Okay, so you don’t have an iota of musical talent. You could always build a kalimba that plays itself.

Continue reading “Thumbs Up To This Pico MIDI Kalimba” →

Get To Know Touch With This Dev Board

December 31, 2022 by Jenny List 5 Comments

In the catalogue of the Chinese parts supplier LCSC can be found many parts not available from American or European suppliers, and thus anyone who wants to evaluate them can find themselves at a disadvantage. [Sleepy Pony Labs] had just such a part catch their eye, the Sam&Wing AI08 8 channel capacitive touch controller. How to evaluate a chip with little information? Design a dev board, of course!

The chip tested is part of a family all providing similar functionality, but with a variety of interface options. The part tested has eight touch inputs and a BCD output. Said output is used to feed a 74 series decoder chip and drive some LEDs. The touch pads were designed with reference to a Microchip application note which incidentally makes for fascinating reading on the subject as it covers far more than just simple touch buttons.

Whether or not you’ll need this touch chip is a matter for your own designs, however, what this project demonstrates is that with the ready availability of cheap custom PCBs and unexpected parts it’s not beyond reason to create boards just for evaluation purposes.

Perhaps the subject of a previous Hackaday piece would have found this board useful.

The assembled switch PCB in the palm of its creator's hand

TTP223 Brings Simple Touch Controls To A LED Lamp

October 4, 2022 by Arya Voronova 7 Comments

You can buy small modules with capacitive touch detection ICs — most often it’s the TTP223, a single-button capacitive model with configurable output modes. These are designed to pair with a microcontroller or some simple logic-level input, but [Alain Mauer] wanted was to bring touch control to a simple LED strip. Not to be set deterred, he’s put together a simple TTP223-based switch board.

Initially, he made a prototype using one of the regular TTP223 boards as a module, but then transferred the full schematic onto a single PCB. The final board uses an NPN transistor capable of handling up to 3 amps to do the switching job, and Zener-based regulation to provide 5 V for the TTP223 itself from the 12 V input. [Alain] shares the schematic, as well as BOM together with Gerber files for a 2×3 panel in case you’re interested in adding a few of these handy boards to your parts bin.

The TTP223 is a ubiquitous and quite capable chip – we’ve seen it used for building a mouse with low actuation force buttons, a soft power switch, and even a UV-sensing talisman that’s equal parts miniature electronics and fascinating metalwork.

Continue reading “TTP223 Brings Simple Touch Controls To A LED Lamp” →

REMOTICON 2021 // Hal Rodriguez And Sahrye Cohen Combine Couture And Circuitry

March 31, 2022 by Kristina Panos 3 Comments

[Hal Rodriguez] and [Sahrye Cohen] of Amped Atelier focus on creating interactive wearable garments with some fairly high standards. Every garment must be pretty, and has to either be controllable by the wearer, through a set of sensors, or even by the audience via Bluetooth. Among their past creations are a dress with color sensors and 3D-printed scales on the front that change color, and a flowing pantsuit designed for a dancer using an accelerometer to make light patterns based on her movements.

Conductive Melody — a wearable musical instrument that is the focus of [Sahrye] and [Hal]’s Remoticon 2021 talk — was created for a presentation at Beakerhead Festival, a multi-day STEAM-based gathering in Calgary. [Sahrye] and [Hal] truly joined forces for this one, because [Sahrye] is all about electronics and costuming, and [Hal] is into synths and electronic music. You can see the demo in the video after the break.

The dress’s form is inspired by classical instruments and the types of clothing that they in turn inspired, such as long, generous sleeves for harp players and pianists. So [Hal] and [Sahrye] dreamed up a dress with a single large playable sleeve that hangs down from the mid- and upper arm. The sleeve is covered with laser-cut conductive fabric curlicues that look like a baroque interpretation of harp strings. Play a note by touching one of these traces, and the lights on the front of the dress will move in sync with the music.

[Sahrye] started the dress portion of Conductive Melody with a sketch of the garment’s broad strokes, then painted a more final drawing with lots of detail. Then she made a muslin, which is kind of the breadboard version of a project in garment-making where thin cotton fabric is used to help visualize the end result. Once satisfied with the fit, [Sahrye] then made the final dress out of good fabric. And we mean really good fabric — silk, in this case. Because as [Sahrye] says, if you’re going to make a one-off, why not make as nicely as possible? We can totally get behind that.

[Sahrye] says she is always thinking about how a wearable will be worn, and how it will be washed or otherwise cared for. That sequined and semi-sheer section of the bodice hides the LEDs and their wiring quite well, while still being comfortable for the wearer.

Inside the sleeve is an MPRP121 capacitive touch sensor and an Arduino that controls the LEDs and sends the signals to a Raspberry Pi hidden among the ruffles in the back of the dress.

The Pi is running Piano Genie, which can turn eight inputs into an 88-key piano in real time. When no one is playing the sleeve, the lights have a standby mode of mellow yellows and whites that fade in and out slowly compared to the more upbeat rainbow of musical mode.

We love to see wearable projects — especially such fancy creations! — but we know how finicky they can be. Among the lessons learned by [Sahrye] and [Hal]: don’t make your conductive fabric traces too thin, and silver conductive materials may tarnish irreparably. We just hope they didn’t have to waste too much conductive fabric or that nice blue silk to find this out.

Continue reading “REMOTICON 2021 // Hal Rodriguez And Sahrye Cohen Combine Couture And Circuitry” →

Capacitive Touch Controller For FPGAs

October 24, 2021 by Bryan Cockfield 10 Comments

Most projects that interface with the real world need some sort of input device. Obviously this article is being written from a standardized “human interface device” but when the computers become smaller the problem can get more complicated. We can’t hook up a USB keyboard to every microcontroller since we often only need a few buttons, but even buttons can be a little bit too cumbersome for some applications. For something even simpler, we would like to turn your attention to capacitive touch controllers.

Granted, these devices are really only simpler from a hardware perspective. Rather than a switch that can be prone to failure either when its moving parts break or its contacts become corroded, a capacitive touch button only needs a certain conductive area on something like a PCB, along with a few passive components, to work. The real difficulty is in the software, so this project aims to make it simpler to bring these sort of devices to any FPGA that needs some sort of interface like this. It can operate in stand-alone mode or in a custom user interface, and was written to be platform-independent in VHDL without the need for any dependencies or macros.

The project’s page goes into a great amount of detail on how capacitive touch sensors like these work in general, and describes the operation of this specific code as well. Everything is open source, so it’s ready to be put to work right away. If you need capacitive touch capabilities on something like a microcontroller, though, take a look at this tiny Atmel-powered musical instrument instead.

Mice with capactive sensors instead of buttons. Designed for people with low mobility.

Capacitive Mouse Built For A Friend Makes For A Touching Tale

August 30, 2021 by Kristina Panos 26 Comments

Those tiny switches inside your mouse may be rated for 50 million clicks or more, but your fingers will likely wear out much sooner than that. Trust us — mouse arm and/or hand fatigue is no fun at all. If you’ve never had the displeasure, just try to imagine not being able to click or move the mouse around without extreme discomfort.

For this year’s Hackaday Prize, [BinSun] hacked together a capacitive mouse for a friend who has ALS. Instead of micro switches, it uses touch sensors to detect left and right clicks and LEDs to indicate when a click has taken place. That makes us think that haptic feedback could be cool, but it might get old quickly, or even worse, you might get used to it after a while and not feel it anymore.

This mouse would be a good alternative for anyone with limited mobility from any condition — ALS, arthritis, trigger finger, or carpal/cubital tunnel syndrome. It would also benefit anyone who wants to mouse much more stealthily, like in a library, a small shared space, or late at night. The only downside we can see is that you’d either have to get used to hovering your fingers, or else learn to rest them out of the way of the capacitive buttons. Otherwise, you’re gonna actuate them more often than you really want to.

If you want to build one of these, you’ll find a nice set of instructions over on IO that includes the minor modifications necessary to make the TTP223 capacitive modules sensitive enough to detect the presence of a finger. All you really have to do is bridge a couple of pads, add a capacitor and remove the SMD LEDs. [Bin Sun] says this is an ongoing project. He’s gotten a handful of beta testers involved at this point, and is planning to make a dedicated PCB pretty soon. Squeak past the break for a couple of brief demonstrations.

The right kind of mouse can save your limbs, sure. Hack together a different type of mouse, and you might be able to save your crops from elephant raids.

Continue reading “Capacitive Mouse Built For A Friend Makes For A Touching Tale” →