Locket: a connected necklace for couples

Annah Amici
8 min readJan 1, 2017


Project Goals

In the Spring of 2016, I had the opportunity to dedicate a semester to a very open-ended research studio with the following goals:

  1. Reinvent/Rethink: identify an interactive UI problem or scenario
  2. Different/Better: work through radically different or better ideas & solutions
  3. New Thoughts: create something to fundamentally change how we think about our interaction with technology

From these very broad goals, I looked outward at emerging wearable technology and screen-less user interfaces, as well as inward, at what sort of problems people around me encounter in everyday life.

Since I met my wife at university, we would always be apart during the day. Sending messages back and forth was never a problem, but we didn’t always have the time to have in-depth discussions around the interesting topics that came up. Then, when we were back together in the evening, those little topics would be far in the back of our minds or lost in the message history.

Busy couples miss out on small, yet easily-forgettable, moments in their partner’s life when apart. Bookmarking these moments until the couple is reunited will help them connect more deeply in-person.

Below, the three project goals have been adapted to this issue:

  1. Reinvent/Rethink: reinvent bookmarking, diary-keeping, passive wearables in the domain of time-strapped couples
  2. Different/Better: passive notifications provide an alert but do not distract, creating a sense of expectation & looking forward to reuniting
  3. New Thoughts: can we use tech/wearables/apps to be a better partner?

Market Analyses


In looking for inspiration, I of course did a lot of competitive analysis on the wearable market. Stand-out products/concepts include:

  • Misfit Shine An unobtrusive UI that uses taps and cleverly hidden LEDs to show your percentage of total points for a day as well as time
  • Tactilu, TapTap, RingU, PillowTalk All products that transfer some form of touch (or heartbeat!) from one wearable device to another, mostly intended for those in long-distance relationships.
  • Ringly, Omate Ungaro Rings functioning as push notifiers for messages
  • purple A locket with a screen that pulls social media photos

Tech to Connect

Additionally, I looked at other ideas people had to help couples or family/friends connect more deeply on a daily basis, like this set of connected lights for families across the globe: Good Night Lamp.
By far, though, the concept that stood out the most to me was Dhruv Jain’s Jog Call, an MIT Media Lab project that encouraged couples to exercise in the morning through a device that moves two little birds ever closer together the more the partners run together (while I would love to have one of these, rare is the day Edelweiss gets up before 8, let alone goes out to run).

User Research


The next phase of research was gathering user data! First, I set up a Google Survey to gauge interest among couples for some kind of wearable device used to keep in touch.


With 30 answers from the survey, I began to prepare for user interviews. I interviewed three couples and focussed on how and how often they keep in touch throughout the day, what kinds of things they send/save/talk about, and their opinions on wearables, especially necklaces, towards which I had been gravitating for a while.

A locket is very intimate, in that it is close to one’s heart, has the ability to be public or private (inside/outside of shirt) and often carries significance for the wearer.

From the interviews, I found that other couples do share the same difficulties my wife and I have around keeping in touch during the day. The other couples liked conversing and sending lots of messages, but often didn’t have the time to have deeper conversations at that moment. “Remind me to tell you about this later!” was commonly heard. They would also be sad or concerned if their partner didn’t/couldn’t reply to a funny or interesting message they sent. Regarding the necklace form factor, important issues brought up included personalisation and non gender-specific design, as well as the possibility to wear it as a ring or watch (à la the Misfit Shine).

Defining Form & Function

With competitive analyses and user research in hand, I began the process of actually creating the thing!

LEFT: feature ideation, RIGHT: possible form factors and interaction methods

I began by defining my system as a wireless necklace paired with a phone app. After some time, I boiled down the necklace’s features to a set of inputs:

  • Tapping to take a screenshot of your connected phone
  • Double-tapping to type a short message on your connected phone
  • Tap-and-hold to record a short voice message through the locket

And outputs:

  • a gentle vibration when a message has been received
  • a light that increases in intensity based on how many messages have been received

The paired app functions as a messaging app, however, messages sent by each partner are locked from view until the two lockets are in physical proximity to each other. This ‘restriction’ means that when one partner sends a message, the receiving partner gets only a gentle vibration and an increase in light on the locket. Only when the two reunite at the end of the day can each view the other’s messages, thus increasing face-to-face communication and helping couples connect more deeply.

simple user flow of necklace & app


Since I had the time and resources, I decided to go ahead and prototype this idea as far as I could. With an Arduino, very limited electrical engineering skills (but knowledgable friends), and an array of 3D printers, I set out.

UI Mockups

First, I quickly mocked up some screens from the app, as I thought I might have time to hack together a quick HTML prototype (nah, time constraints).

LEFT: text, photo, voice input screen, MIDDLE: messages calendar view, RIGHT: a day’s stream of messages, with some still locked

Lo-fi Artefact Prototype

By this time, things were getting down to the wire and I needed to prioritise my deliverables. I decided to focus all of my remaining time into making a prototype of the locket itself, since that would challenge me the most in terms of new skills.

I began with cardboard, a spring, tape, and string in order to quickly get a feel for its size, placement, and weight. I then took those rough measurements to Cinema 4D/SolidWorks to model some basic forms from my research and sketching before printing them out. Working with physical units and accounting for fit was definitely a new challenge here.

LEFT: ugly prototype, RIGHT: failures and hacked up test prints

Electrical Components

From there, I had to source the following electrical components for minimum viable functionality:

  • Arduino Uno, breadboard, lots of wires
  • old iPhone vibration motor (hard to solder, do not recommend)
  • cheap white LEDs
  • standard buttons

Arduino Coding

Tweaking thicknesses and placements of geometry and waiting for print after print gave me time to wire up all the components and write some relatively simple Arduino code. Most of my time coding was spent implementing a crude version of my idea for the LED to increase in brightness. In this prototype, there are 5 states:

  • 0 messages, no light: analogWrite(ledPin, 0)
  • 1 message, low light: analogWrite(ledPin, 85)
  • 2 messages, medium light: analogWrite(ledPin, 170)
  • 3 messages, max light: analogWrite(ledPin, 255)
  • 4+ messages, max light & blink once:
analogWrite(ledPin, 255)
digitalWrite(motoPin, HIGH);
digitalWrite(motoPin, LOW);
check that tiny vibromotor spinning around!

3D Printing

For final 3D print (file timestamped 2:12am, 20 May!), I used standard coloured ABS for the backing and front cover and some cool green Ninjaflex TPE for the flexible centre button. The Ninjaflex had to be printed on a LulzBot, since the diameter was too thick for the MakerBot to handle.

buzz buzz buzz

Eventually, everything was snapped in place, wired together, debugged, and documented and I could call it a night, but not before putting it around my neck and feeling it in action for the first time. So satisfying!

Result & Post-Mortem

There are, of course, lessons to be learned from everything. Were I to return to this project, I would improve on things from both technical and design standpoints.

Edelweiss, trying her hardest not to laugh

Technical Improvements

First, I would use Adafruit Floras and solder down more components to eliminate the messy wires. Also, I would put more time into user testing and refining the 3D design and print quality of the lockets themselves.

Interaction Issues

Working through prototyping, I also slowly came to the serious realisation that the button on the locket is almost unnecessary. I was stuck on the idea of someone tenderly holding a locket that I didn’t focus enough on the disconnect between the content (on phone/in world) and the device. All of the inputs could live in the phone, while the locket still receives pings.

If this necklace were ever implemented in a standalone or existing messaging system, there would also need to be a major rethink of the on-screen UI. One big issue identified was that locking messages from being viewed could be too restrictive. Maybe the user could toggle locking of messages?

Final Words

Regardless, this project was incredibly valuable and was as successful as I could have hoped, as my personal goal was to take advantage of the resources I had at university to dip my feet into as many different disciplines as I could. This was the first time I had every worked with electrical components and and Arduino and the first time I approached 3D printing from a more engineering perspective than a design perspective. And I know that it won’t be the last time.

Until next month…

These articles document monthly projects I am doing to expand my knowledge across the wide range of disciplines that can be loosely associated with ‘design’. Previous works here: aja5174.cias.rit.edu & amicidesigns.tumblr.com



Annah Amici

Design encompasses all. Thoughts and ideas on health, social interaction, programming, UX, and more. Formerly at Grayscale in HK, now at Lab Zero in SF.