Haptic Soft Buttons Speak(er) To Your Sense Of Touch

April 24, 2025 by Tyler August 7 Comments

There’s just something about a satisfying “click” that our world of touchscreens misses out on; the only thing that might be better than a good solid “click” when you hit a button is if device could “click” back in confirmation. [Craig Shultz] and his crew of fine researchers at the Interactive Display Lab at the University of Illinois seem to agree, because they have come up with an ingenious hack to provide haptic feedback using readily-available parts.

The “hapticoil”, as they call it, has a simple microspeaker at its heart. We didn’t expect a tiny tweeter to have the oomph to produce haptic feedback, and on its own it doesn’t, as finger pressure stops the vibrations easily. The secret behind the hapticoil is to couple the speaker hydraulically to a silicone membrane. In other words, stick the thing in some water, and let that handle the pressure from a smaller soft button on the silicone membrane. That button can be virtually any shape, as seen here.

Aside from the somewhat sophisticated electronics that allow the speaker coil to be both button and actuator (by measuring inductance changes when pressure is applied, while simultaneously driven as a speaker), there’s nothing here a hacker couldn’t very easily replicate: a microspeaker, a 3D printed enclosure, and a silicone membrane that serves as the face of the haptic “soft button”. That’s not to say we aren’t given enough info replicate the electronics; the researchers are kind enough to provide a circuit diagram in figure eight of their paper.

In the video below, you can see a finger-mounted version used to let a user feel pressing a button in virtual reality, which raises some intriguing possibilities. The technology is also demonstrated on a pen stylus and a remote control.

This isn’t the first time we’ve featured hydraulic haptics — [Craig] was also involved with an electroosmotic screen we covered previously, as well as a glove that used the same trick. This new microspeaker technique does seem much more accessible to the hacker set, however.

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Haptic Baby Monitor Gets The Wearer’s Attention

August 11, 2022 by Tom Nardi 10 Comments

Anyone who’s ever slept through a morning’s alarm can tell you that sounds, even loud piercing ones, don’t always wake a person out of a deep sleep. Similarly, hearing a baby cry on the other side of the monitor might not always wake a parent up in the middle of the night. So what’s the solution? This haptic baby monitor created by [Guy Dupont] certainly looks like it has some promise.

[Guy] picked up a fairly standard baby monitor from VTech and popped it open to see how he could tie a vibration motor into the original circuitry. He originally thought he’d have to do some signal processing magic to figure out the amplitude of the audio, but then he realized that the five LEDs on the front of the unit that light up to indicate the audio level were already doing the hard work for him.

Detecting audio level by reading the status of the LEDs.

So he wired each of the LEDs up to the pins of a Seeed Studio XIAO nRF52840 microcontroller, and wrote some code that would poll their status a few hundred times per second. Dividing the total number of LEDs by the count of how many are currently illuminated gives him a nice average that he can use to set the intensity of the vibration motor that he’s built into a stretchy armband.

For extra points, [Guy] is also using the Bluetooth capability of the XIAO to provide a rudimentary configuration service — just connect up to the MCU with a Bluetooth serial application on your computer or phone, and fire off a value between 0 and 10 to augment the motor’s intensity. There’s also a BLE characteristic which can be read from a client device to determine the currently detected audio amplitude, which could be used to chart how well the baby is sleeping over time. Alternately, as demonstrated at the end of the video, you could use it to play Flappy Bird.

It’s an elegant modification that could potentially hold promise for parent’s who need a bit of extra help keeping tabs on their miniature humans. This isn’t the first time we’ve seen hackers try to improve upon the classic baby monitor, but this is arguably the most approachable attempt we’ve seen to date.

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A mechanical keyboard with a haptic knob and E-ink display

Smart Modular Keyboard Sports An E-ink Display And A Haptic Feedback Knob

July 28, 2022 by Robin Kearey 19 Comments

While most people may think that a keyboard is just a board with keys, those who read Hackaday will no doubt know that there’s an infinite variety of beautiful designs to suit any use case. [Peng Zhihui] is the latest to impress us with an excellent custom keyboard that packs several unusual features (video in Chinese, with English subtitles, embedded below). What started out as a simple lockdown project turned into what [Zhihui] imagines to be the ultimate keyboard for his daily tasks. At first glance it might look like just another custom keyboard with mechanical switches, but when you look inside you’ll find it full of clever design tricks and neat features.

When he started on the design of the main key area, [Zhihui] could have used any of the open-source keyboard frameworks. Instead, he decided to do everything himself in order to obtain maximum performance and configurability. This went all the way down to the readout circuitry: rather than wiring the switches in a matrix, as most keyboards do, he used a set of shift registers. This enables the main ARM controller to read out every key separately, eliminating ghosting and allowing any number of keys to be pressed simultaneously. The shift registers are driven by a 4 MHz SPI clock, which means that a full scan of all keys takes just 40 microseconds.

That is brilliant, but what makes this project really interesting is an extension module on the left side of the keyboard that turns it into what [Zhihui] calls a “smart keyboard”. The bottom part of this module has an E-ink display that can show a variety of useful information: current memory usage, email notifications or simply the weather forecast.

Next to the big E-ink screen is a tiny OLED display that works in tandem with a haptic feedback knob. Based on a brushless DC motor, this knob can be configured in various ways to perform several different tasks. It can be set to friction-less spinning mode, which is useful for quickly scrolling through long documents. It can become a multi-level switch to enable or disable features, or a volume knob with virtual end stops. There’s even an option to use it as a physical indicator for things like the current CPU usage.

The keyboard also houses a USB hub to attach other gadgets, as well as a lithium battery to power the haptic knob, since it uses more power than a standard USB 2.0 port can deliver. There’s even a little capacitive touch strip below the space bar, which allows you to use one of your thumbs to switch between different tabs or to use quick copy/paste functions.

If all of this sounds like your idea of a perfect keyboard, then you’ll be pleased to hear that [Zhihui] plans to open-source all hardware and software designs once he’s cleaned up his code. Until that time, you may want to read up on the working principle of a haptic smart knob, or find out what’s the most efficient way to read out a certain number of buttons with a microcontroller.

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Balloons Are The User Interface Of The Future

July 26, 2022 by Lewin Day 12 Comments

We’ve seen all kinds of interfaces come and go over the years, from keyboards and mice to lightpens and touchscreens. Now, a group of researchers at the University of Tokyo have built a device that enables haptic interaction with a balloon.

It takes quite a rig to achieve this feat. A vaguely-spherical frame is used, which mounts eleven airborne ultrasound phased arrays, or AUPA. Each phased array is made up of many ultrasonic transducers, with the machine having 2739 individual transducers in total. The phased arrays are controlled in such a way to create a sound field that moves the balloon around and holds it in various desired positions. Closed loop control is achieved with the use of stereo cameras, which track the balloon’s position at high speed.

The system allows the balloon to be moved around quickly in three dimensions. Plus, a user can touch and interact with the balloon directly as it floats in mid-air. They can even drag and redirect the balloon, which can be tracked by the stereo camera system.

The research team don’t highlight any particular applications for this technology at this stage. We’re not expecting the Touch Balloon on next year’s Surface Pro or the next MacBook, that’s for sure. However, it’s great fun to look at and likely has some creative applications that we can’t think of off the top of our heads. Share yours in the comments.

The 2022 Hackaday Prize has a special focus on odd inputs and peculiar peripherals, so be sure to check out that whole scene. Video after the break.

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Seeing-Eye Shoes Pair Computer Vision With Haptic Feedback

May 12, 2021 by Kristina Panos 21 Comments

Over the years, we’ve seen plenty of projects that use ultrasonic or time-of-flight sensors as object detection methods for the visually impaired. Ultrasonic sensors detect objects like sonar — they send sound pulses and measure the time it takes for the signal to bounce off the object and come back. Time-of-flight sensors do essentially the same thing, but with infrared light. In either case, the notifications often come as haptic feedback on the wrist or head or whatever limb the ultrasonic module is attached to. We often wonder why there aren’t commercially-made shoes that do this, but it turns out there are, and they’re about to get even better.

The shoe’s view — safe walking space is delimited with color. Image via TU Graz

Today, Tec-Innovation makes shoes with ultrasonic sensors on the toes that can detect objects up to four meters away. The wearer is notified of obstacles through haptic feedback in the shoes as well as an audible phone notification via Bluetooth. The company teamed up with the Graz University of Technology in Austria to give the shoes robot vision that provides even better detail.

Ultrasonic is a great help, but it can’t detect the topography of the obstacle and tell a pothole from a rock from a wall. But if you have a camera on both feet, you can use the data to determine obstacle types and notify the user accordingly. These new models will still have the ultrasonic sensors to do the initial object detection, and use the cameras for analysis.

Whenever they do come out, the sensors will all be connected through the app, which paves the way for crowdsourced obstacle maps of various cities. The shoes will also be quite expensive. Can you do the same thing for less? Consider the gauntlet thrown!

We could all use some navigational help sometimes. Don’t want to look like a tourist? Get turn-by-turn directions in the corner of your eye.

Thanks for the tip, [Qes]!

Virtual Reality Gloves Aim To Improve Interactivity

April 15, 2021 by Lewin Day 13 Comments

Virtual reality is a slow-moving field in some respects. While a lot of focus is put on optical technologies and headsets, there’s a lot more involved when it comes to believably placing a human being in a virtual environment. So far, we’ve gotten a good start at the visuals and head tracking, but interaction technology is still lagging behind a lot. [Lucas] is working in just that area, iterating heavily on his homebrew VR gloves.

The gloves consists of potentiometers, fitted with spools and attached to the tip of each digit on a wearer’s hand by a string. As the user curls their fingers, the potentiometers turn and the position of the fingers can be measured. The potentiometers are all read via an Arduino, which communicates back to a PC via USB. A custom driver is then used to interact with Valve’s SteamVR software, allowing the glove to be used with a wide variety of existing software.

Thus far, the system is merely tracking finger position, but the spool and string based design is intended to support motors down the line for each finger to create resistance, so the user can gain the feeling of touching and interacting with virtual objects. The project has the potential to be a cheaper, more accessible alternative than current off-the-shelf solutions. We’ve seen other hand-tracking gloves before, too – though none that track the spread of a wearer’s hand as well as the finger extension. If you’re working on precisely that, please do drop us a line. Video after the break.

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Gaming With 1 Horsepower Of Rumble Feedback

April 14, 2021 by Lewin Day 14 Comments

Force feedback took off in a big way in the late 90s, bringing a sense of realism to flight sticks and racing wheels that hadn’t been there before. Its cheaper haptic cousin was rumble feedback via vibration motors, which does add a little something but it’s more an idea of a feeling than anything relevant to real life. It’s also usually pretty weak, but [teenenggr] has a way around that.

The build takes a regular Playstation controller, and disconnects the internal rumble motors. The controller’s motor output is instead linked to an Arduino Uno’s digital input. When the Arduino detects the rumble motor signal switching on, it turns on a relay, supplying power to a hefty one horsepower induction motor, fitted with an eccentric weight.

What happens next is pure chaos. Essentially equivalent to throwing a brick in a washing machine, the motor shakes the entire desk at the slightest hint of rumble signals from the gain. Sustained vibration commands, such as when firing machine guns in Crysis, flung [teenenggr]’s monitor from the desk. Even with it taped down, game play quickly became impossible as he inadvertently hits ALT-Tab and leaves the game while trying to hang on to the desk for dear life.

Is it a useful hack? No, but it would make an excellent prank if bolted underneath your friend’s gaming rig for a laugh. With that said, the intense vibration probably won’t do any good for mechanical hard drives, anything with edge connectors, or just their computer in general. It’s a big step up from the last [teenenggr] project we featured – a rumble feedback mouse. Video after the break.
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