Haptic Feedback in the Da Vinci Surgical System

The Da Vinci Surgical System is a robot built by Intuitive Surgical. After being approved for use by the FDA in 2000, it has been adopted by surgeons performing a wide range of minimally invasive procedures, including prostatectomies, cardiac valve repair, and gynecologic procedures. As of June 30, 2014, approximately 3,100 Da Vinci robots were installed worldwide, with each unit costing roughly $2 million. The primary innovation of the Da Vinci system is the surgeon’s console: an immersive visualization system that takes an ordinary laparoscopic image and projects it to a binocular display, enhancing the dexterity with which a surgeon can perform several procedures. For the patient, the Da Vinci system typically provides a reduced amount of pain and blood loss, frequently resulting in a shorter hospital stay and faster recovery period. Continue reading “Haptic Feedback in the Da Vinci Surgical System”

Getting Started with Haptic Feedback (Arduino Guide)

The DRV2605 breakout board from Adafruit.
The DRV2605 breakout board from Adafruit.

Adafruit provides a breakout board for the DRV2605 haptic driver from Texas Instruments. Although the example tutorial included with the product describes a quick way to set up the driver with an eccentric rotating mass (ERM) motor, we prefer using a linear resonant actuator (LRA) for increased precision and enhanced haptic feedback. You can use the breakout board with an Arduino Uno to quickly make a prototype of a system that delivers precise vibrotactile cues.

Materials & Supplies

Hardware

Software

Additional Resources

Creating Haptic Feedback

Step 1: Soldering

The DRV2605 breakout board attached to a LRA.
The DRV2605 breakout board attached to a LRA.

Solder the header strip onto the breakout board, and solder the LRA onto the breakout board. After this step, your DRV2605 breakout board should look like this:

Step 2: Wiring and Hookup

  • Connect VIN on the DRV2605 to the 5V supply of the Arduino
  • Connect GND on the DRV2605 to GND on the Arduino
  • Connect the SCL pin to the I2C clock SCL pin on your Arduino, which is labelled A5
  • Connect the SDA pin to the I2C data SDA pin on your Arduino, which is labelled A4
  • Connect the IN pin to an I/O pin, such as A3

Step 3: Testing and Creating Effects

Adafruit provides a very useful Arduino library for the DRV2605 that you can use to get started. In particular, we recommend looking through the example code to get an idea of the effects you can produce. In page 57 and 58 of the DRV2605 datasheet, you can find a table of all the effects you can produce “out of the box.”

Step 4: Creating Your Own Waveforms

Since you can also set the intensity of the LRA in realtime, you can design your own waveforms and effects by changing the value over time. Adafruit also provides an example for setting the value in realtime on Github. You can combine this example code with a waveform design tool like Macaron to customize the feedback provided by your new Arduino-powered haptic device!

Macaron and the Future of Haptic Editors

Screenshot of the Macaron interface.
A screenshot of the Macaron haptic effects editor.

Earlier this week, we had the pleasure of talking to Oliver Schneider, a graduate student and researcher at the University of British Columbia. Working at the Sensory Perception & Interaction Research Group, Oliver spends most of his days developing new software and hardware interfaces that engage our sense of touch. He described various techniques he used to create development tools and interfaces for creating rich tactile effects, including Haptic Jazz – a system for taking improvisational input on a tablet and translating it in real-time into a vibrotactile sensation. Continue reading “Macaron and the Future of Haptic Editors”

The Future of 4D Home Cinema: A Haptic Effects Track

Diagram of 4D Movie Theater
Diagram of a 4D movie theater from Wikipedia.

With the rise of Netflix and Youtube as dominant platforms for video consumption, fewer people are visiting theaters to watch movies. An increasing amount of multimedia content will be designed for the home theater as these streaming services grow their libraries. Netflix users consume content on whichever screen is available: a laptop, tablet, or smartphone. As the user experience for content consumption shifts towards mobile applications and at-home viewing, the interactive elements of 3D and 4D film previously reserved for movie theaters will transition to technologies easily adopted by households.

Good video is engaging – it tells a compelling story with excellent production value. Since there is increasing competition for viewership between different streaming platforms, devices, and content production studios, there is an increasing demand for differentiated content – content that provides a unique experience to its viewers. Continue reading “The Future of 4D Home Cinema: A Haptic Effects Track”

Temperature Feedback with the Thermoelectric (Peltier) Effect

Photograph of a thermoelectric cooler (Peltier diode)
A Peltier diode available from Sparkfun Electronics.

Vibrotactile pulses (e.g. the buzzing of a cell phone or game controller) can provide users with real-time feedback in a computer interface, but it’s not the only way to transmit information through the sense of touch. Modulating the temperature of the surface of a device can also provide additional information to users.

When a current flows through a junction between two different conductors, heat can be generated or removed from the junction. This phenomenon is called the Peltier effect, named after physicist Jean Charles Athanase Peltier. Different conductive materials that exhibit a Peltier effect will generate or remove different amounts of heat proportional to the amount of current running through the junction – the Peltier coefficient measures how much heat is carried for every unit of charge flowing through the device. Continue reading “Temperature Feedback with the Thermoelectric (Peltier) Effect”

The Haptic Breakdown: What’s Inside Your Smartwatch

In this post, we’ll look at the different ways that some of the most popular wearables implement haptics. Outside of the Apple Watch, most wearables use a simple eccentric rotating mass motor for haptic feedback.

Apple Watch

The Apple Watch was first introduced in the fall of 2014 and has since become the world’s best selling wearable device. It was Apple’s first introduction of its “Taptic Engine”, which provides haptic feedback for alerts and notifications. While the design of the Taptic Engine module is proprietary, it is likely a customized linear resonant actuator.

Continue reading “The Haptic Breakdown: What’s Inside Your Smartwatch”

Electrovibration In Ungrounded MacBook Pros

My 2011 15” MacBook Pro

A few weeks ago, I noticed that the aluminum enclosure of my unibody Macbook Pro had a strange texture when I brushed my hand across the surface. After some tinkering, I noticed that this only happened when the device was being used while charging and that it only happened when using my shorter, 2-prong, power cable—leading me to believe there was some sort of current leakage happening.

Continue reading “Electrovibration In Ungrounded MacBook Pros”

Tactile Illusions: Interesting Ways Our Brains Fail

Waterfall by MC Escher
If you haven’t seen enough optical illusions, check out some MC Escher artwork.

If we’re honest about shortcomings in human physiology, optical illusions would be labelled “Brain Failures.”

– Neil DeGrasse Tyson

When we think about the ways our perception plays tricks on us, optical illusions come to mind first. They’re not the only kind of sensory illusions, though. Tactile illusions also illustrate the fascinating ways that our perception ‘fails’ to reflect reality. In this post, we describe several different types of tactile illusions.

Continue reading “Tactile Illusions: Interesting Ways Our Brains Fail”

How It Works: Linear Resonant Actuators

Diagram of a linear resonant actuator.
Diagram of the construction of a linear resonant actuator.

A linear resonant actuator is a vibration motor that produces an oscillating force across a single axis. Unlike a DC eccentric rotating mass (ERM) motor, a linear resonant actuator relies on an AC voltage to drive a voice coil pressed against a moving mass connected to a spring. When the voice coil is driven at the resonant frequency of the spring, the entire actuator vibrates with a perceptible force. Although the frequency and amplitude of a linear resonant actuator may be adjusted by changing the AC input, the actuator must be driven at its resonant frequency to generate a meaningful amount of force for a large current.

Continue reading “How It Works: Linear Resonant Actuators”

Electrovibration and Touchscreens: Creating Virtual Textures

Graph of Perceived Friction by Voltage
A higher voltage results in a higher perceived friction.

In 1950, Edward Mallinckrodt, a researcher at Washington University in St. Louis, accidentally discovered the phenomenon of electrovibration (also known as electrostatic vibration). He noticed that a brass electric light socket had a different texture when a light was burning than it did when the light was turned off. Along with a team of researchers, he began exploring the phenomenon in more detail by running experiments using an aluminum plate with insulating varnish. They wrote:

If the dry skin of one’s finger is moved gently over a smooth metal surface covered with a thin insulating layer, and the metal is connected to the ungrounded side of an 110-v power line, the surface has a characteristic feeling that disappears when the alternating voltage is disconnected.

Continue reading “Electrovibration and Touchscreens: Creating Virtual Textures”