Haptic Technology | From the Archives, Feb. 2015

Karthik Subramaniam
11 min readAug 23, 2018

From the Archives is a series that pulls from a collection of research papers written for a high school STEM program between the years 2013–2015. These papers pushed students to investigate a subject, formulate questions and further developments upon the matter, and ultimately expand knowledge through some form of experimentation and execution. While much of the information and personal opinions presented have changed since the time of writing, I wanted to publicly document my thinking and explorations from that time.


Over the past five years, various forms of new technology and devices have been introduced. Unfortunately, since that time, the level of innovation and ingenuity present in these devices has arguably declined, leaving both creators and consumers itching for the next development in any tech-related field. A group of devices is expected to rise and fill this hole in the year 2015, dubbed wearables. A wearable is any electronic that “is incorporated into items of clothing and accessories [and] can comfortably be worn on the body” [13]. Although the year 2015 is mentioned specifically above, wearables that act as accessories to smartphones have been available to the general public for many years: in 2009, Samsung introduced one of the very first smartwatches [8].

Since then, various companies have debuted their own smartwatches, including Pebble, LG, and Motorola; however, despite the large number of smartwatches that entered the market in 2014, mainstream consumers still have not found a need to use these devices, and therefore are not using them. In 2013, less than only one million Samsung smartwatches were sold, with his company being the highest seller of such devices during that year [2]. In comparison, Samsung sold 40 million units of their Galaxy S4 smartphone within six months of launch, demonstrating that the demand for wearables pales in comparison to the market’s hunger for new phones. A more adept figure to use for contrast is Samsung’s own estimate of smartwatch sales. Samsung’s Chief Analyst Michael Wolf predicts that sales will exceed 100 million units by the year 2020 [11]. While this figure is not a projection for the year 2013 specifically, if the unit figure prediction is divided by the eleven years between 2020 and 2009, Samsung should have sold approximately 9 million smartwatches every year since the introduction of their wearable. It can be argued that sales are not going to reach that figure in the first year, as people take time to adopt a product, but an 8 million unit disparity is still stretching the qualification of success.

It is clear to see from the figures presented that, as of yet, consumers have not embraced the newest form of technology racing into their lives and onto their wrists. This leaves 2015 ripe for one more company to attempt to bring the wearable category life, a company that has proved to have a knack of helping people crave a product they did not realize they needed until it was shown to them: Apple. The most recent form of evidence to support this can be found in the sales of big-screened smartphones. In the 2014 holiday quarter, Apple sold 74.4 million units of their first-generation bigger iPhones [8]. Conversely, Samsung only sold 20 million units of their fifth-generation big-screen Galaxy phone [1]. Although smartphones with larger displays have been around for years, consumers clearly show an interest when Apple releases their spin on a previously tried product. In April, Apple will release their newest product, Apple Watch, which will be their first foray into the wearable market. The Apple Watch brings various new technologies to the industry, some of which revolutionize the way people communicate or exercise. One of the biggest advancements, though, is a concept called taptic feedback, which will essentially change the manner in which people interact with devices themselves.

Taptic feedback, previously known as haptic feedback, is produced by a linear actuator within Apple Watch, and serves to deliver notifications not through a traditional vibration, but through a tapping sensation. Before taptic feedback and its applications can be explored, both linear actuators and haptics must be understood. A linear actuator, as the name suggests, is a machine that creates motion in a straight line, as opposed to the circular motion of a traditional vibration motor system [7]. With Apple Watch, when a notification is received by the device, programming commands the linear actuator to push downwards with force, and then retract back to its original state. This motion, in conjunction with a precisely timed and very subtle vibration creates haptic feedback, also known as kinesthetic communication [3]. While haptic technology has been employed in past smartphones, primarily to provide a clicking sensation when a person is typing on an on-screen keyboard or even mimic textures when a finger is dragged across a display, the use of haptics has not been used in a mainstream capacity for notifications [4]. While it remains to be seen whether the taptic engine and its implementation by Apple is effective, as the Apple Watch only goes on sale in April 2015, the other use cases of such technology are endless, and will be discussed in this paper.

Further Development

The technology used in Apple Watch’s taptic engine can be carried over to other Apple products, specifically iPhone; utilizing a taptic engine rather than a traditional vibration system in phones would alleviate two issues. The first problem that would be solved is the annoying buzz produced when a phone is placed on a desk, which would be replaced with a sound more akin to a person tapping on their desk. The sound of a single tap on a desk is very unassuming and also a sound that people have subconsciously accustomed to, as it is very common in life. Through the commonality of the tap, people have also learned to automatically tune out such noises and not be bothered by it. This can be placed in direct contrast to the sound of a phone vibrating, which is very distinctive and cannot be blocked out because people still have not gotten used to such a noise in the near-decade that smartphones have been widely available. This leads to the second problem that would be solved: the content of a notification would be unaccessible to unauthorized users. Layered notifications enabled by the taptic engine would require multiple processes to be completed before a notification can be viewed, adding privacy. When a person receives a notification, their device will remain off; however, if the accelerometer picks up motion within a specific range of time after this notification (perhaps from a person removing the phone from their pocket or picking it up off a desk), the display will automatically activate. From this lock screen, only the sender and respective application of the notification are visible. Additional content can be viewed here without unlocking through a native facial recognition software: this software would utilize the front facing camera to view a visage, and identify specific points on the face to verify identity. Finally, in order to unlock the device and reply to the notification, or bypass the facial recognition step, a person needs only enter their fingerprint using Touch ID.

Personal Connection

The creation of taptic feedback and its implementation in devices other than the Apple Watch, such as iPhones, would apply to both my life and the lives of my peers in a variety of manners. First, my transition from middle school to high school has incurred a plethora of changes in my life, yet the most prominent one, to me, is my increased social life. Now, I am barraged by thousands of text messages every day during both school and at home. While my own notifications do not bother me, the incessant sounds of vibrations may present an issue for my peers and parents. By the same token, the vibrations of my friends’ phones become an annoyance to me at times. The situation is always the same: one of my friends retrieves their phone to check a text message, replies, then leaves the device on their desk. Minutes later, they receive a new message, but this time, the phone buzzes against the wooden of the desk, creating the most unpleasant sound. The daily repetition of this event become aggravating very quickly, especially when I am taking a test or reading something quietly; I imagine my peers feel the same way when my own phone vibrates on a table.

Bridging the Gap

Eliminating irritating vibrations from devices is only half of the benefit provided by taptic feedback. The other component here is that notifications received via the taptic engine will also be shown to a user in layers. Such an enhancement applies to a greater range of people and their personal lives, not just myself and fellow teenagers. On the surface level, layered notifications would assist both myself and my peers in keeping notification content private from friends and family. An example of this that is currently highly applicable is relationship problems: many of my friends are undergoing such issues, and are working them out over text. On a conventional notification system, the sender and contents of a text are visible to everyone in the area, yet a device utilizing the taptic engine would do two things differently: first, only the user of the device would be alerted that a new notification exists, and then subsequently discover the contents after the device verifies the identity of the user, perhaps with a Touch ID biometric scan or facial recognition. The same principle can apply to adults, too; however, rather than providing a means to hide sensitive messages, taptic feedback can help keep corporate emails private. In this example, an individual is working for Apple and developing the next version of the iPhone. While in transit on a crowded public subway, the individual receives a sensitive email from CEO Tim Cook regarding a revolutionary new camera module that will be used. On a device without taptic feedback, the notification would appear dictating both the sender and the sensitive content and also be broadcasted to the ten people surrounding the individual of the subway. However, a device with the taptic engine would receive the notification, yet censor all content except Tim Cook’s name. With this information in mind, the individual can evaluate whether or not to find out more about the email in his crowded environment, or wait until a more opportune moment arrives.


While taptic feedback and the use of a linear actuator is an interesting and potentially successful take on a previously developed technology, there are a variety of risks present with its usage, as is the case with any reimagining and innovation. One of the more intriguing questions that I have had since the announcement of Apple Watch relates to the effect of haptics on such small hardware: would the linear actuator and its constant movement would cause any damage to the bottom casing of Apple Watch? Specifically, would the constant tapping of the linear actuator directly against the aluminum or stainless steel of the body cause it to crack or wear thin?

The answer to my question was found with the help of a plethora of sources. First, I ventured to Apple’s website and attempted to find any information of the build materials of Apple Watch. Many of the images on the website of the back of the device displayed an inscription etched into the body, detailing the “ceramic back” [12]. While this was a hint as to what material was used, the phrase was very vague, so I perused the website further, this time looking at the product introduction video, narrated by Senior Vice President of Design Jonathan Ive. The ten minute video revealed many interesting details about the technology and construction, and also provided me with an elaboration on ceramic: the term zirconia [5].

This foreign word was soon deciphered with a quick Google search. Zirconia is a shortening of zirconium oxide ceramic, and is commonly used as “wire…auxiliaries in welding processes [and] as materials for crowns and bridges in the dental industry” [10]. Apple used this particular material in the watch not only because of its “excellent wear resistance and decent toughness” but also for its ability to support wireless inductive charging [6]. This information demonstrates that even though the linear actuator will shift and collide with the body of Apple Watch, fears can be put to rest because the backing of the device was designed with strength and durability in mind.


Although it is easy for one to complain about the negative aspects of an existing technological system, in this case a normal vibration system, some people require additional evidence to be convinced of these shortcomings. In order to gather such evidence, I decided to conduct an experiment rather than conduct additional research; this experiment focused on the relationship between the surface a phone vibrates on and the noise and vibrations felt by both the user and the surrounding people. The setup of this experiment was simple, yet the difficulty was in execution. First, I wore very baggy sweatpants and placed my phone in my right-hand pocket; after doing so, I asked my dad to send me a text message at any random time. The random timing was essential so that I would not anticipate receiving a message and thereby skew the data. After the message was sent, I would check with my family members and tally if they had heard the vibration or not. This process was repeated with me wearing jeans, placing the phone on a countertop, a sofa, and finally a wooden desk similar to the ones used in classes at school.

The data collected revealed two major adjustments that can be made in order to reduce the obtrusiveness of phone vibrations. First, as indicated in the table below, the optimum place to put a phone so that a user is still alerted of a new notification by the sound is virtually unheard by others is jean pockets. These pockets are close enough to a person’s skin that vibrations can be felt, and the material is thick enough that sound does not escape and bother others. If a person was to remove their phone from their pocket and place it on a table, the best surface would be a silestone counter, commonly found in kitchens. On this surface, the vibrations can nigh be felt, but the sounds produced by the vibrations and are low enough that only people in very close proximity, such as the user, can hear it and thereby be alerted to a new notification.

Finally, as suspected, the worst place for a person to lay their phone is a wooden desk in a classroom or any other common place of learning. Evidenced overwhelmingly by data and those involved with the experiment, the sound of a phone vibrating on a desk is very obtrusive and distracting. Furthermore, the vibrations flow throughout the surface of the desk and can be felt by both the person seated there and any others touching it; this combination of irritating noise and a distracting feeling when a notification arrives detracts from a positive concentration.


[1] Boxall, Andy. “2 Million Smartwatches Were Sold Last Year, and Galaxy Gear Is Leading.” Digital Trends. Ian Bell, 13 Feb. 2014. Web. 03 Feb. 2015.

[2] Boxall, Andy. “Top Job Shake up Possible at Samsung after Galaxy S5 Sales Disappoint.” Digital Trends. Ian Bell, 24 Nov. 2014. Web. 04 Feb. 2015.

[3] “Haptic Technology: An Animated Explanation.” International Society for Haptics. GABRIEL ROBLES DE-LA-TORRE, n.d. Web. 03 Feb. 2015.

[4] “Haptics Is Quite Literally The Science of Touch.” What Is Haptics? Immersion Corporation, n.d. Web. 03 Feb. 2015.

[5] Introducing the Apple Watch. Perf. Sir Jonathan Ive. YouTube. Apple, Inc., 30 Sept. 2014. Web. 02 Feb. 2015.

[6] Jasper. “3 Reasons Apple Used Zirconia Ceramic in the IWatch.” Precision Ceramics. Precision Ceramics, Inc, 14 Sept. 2014. Web. 03 Feb. 2015.

[7] Linear Actuator. Digital image. Wikipedia. Wikimedia, 17 July 2007. Web. 03 Feb. 2014.

[8] Marshall, Gary. “Before Apple Watch: The Timely History of the Smartwatch.” TechRadar. Future US, Inc, 13 Sept. 2014. Web. 03 Feb. 2015.

[9] Reed, Brad. “Apple’s IPhone Sales Rampage Shows No Signs of Slowing.” BGR. BGR Media, LLC, 3 Feb. 2015. Web. 03 Feb. 2015.

[10] Sellers, Dennis. “Apple to Use Zirconium Oxide Ceramic Materials for the Apple Watch.” Apple Daily Report. N.p., 26 Nov. 2014. Web. 03 Feb. 2015.

[11] Siegal, Jacob. “Smartwatch Sales Set to Explode, Expected to Top 100M within Four Years.” BGR. BGR Media, LLC, 27 Sept. 2013. Web. 04 Feb. 2015.

[12] “Technology: Innovation In every Interaction.” Apple. Apple, Inc., 14 Sept. 2014. Web. 03 Feb. 2015.

[13] Tehrani, Kiana, and Andrew Michael. “Wearable Technology and Wearable Devices: Everything You Need to Know.” Wearable Devices. Wearable Devices Magazine, 18 Oct. 2013. Web. 03 Feb. 2015.



Karthik Subramaniam

I’m an empathy-driven UI/UX designer who focuses on accessibility, well-being, and joy. Check out my work at www.karthiks.xyz