Design Engineering
Showcase 2020

Holdable Devices: Making Our Phones Good for Our Brains

Federico Tiersen
Design Engineering MEng
Prof. Rafael Calvo
Humanising Technology

Holdable Devices have the ability to sense when you use your phone inattentively or compulsively. They then induce mindfulness and reflection through tactile feedback and abstract visualisations, so you effortlessly regain control of your phone, your time and your mind. User-centred design, psychology and engineering methodologies were combined to create tangible interfaces that tackle the underlying mechanisms of problematic smartphone habits. An integrated hardware and software solution accurately classifies potentially unhealthy behaviours (e.g., scrolling or tapping through social media, frequently checking for notifications). Mechanical and vibrotactile actuation provides well-timed and unintrusive sensory stimulation. A pilot study revealed beneficial impacts on cognition and behaviour and scopes for further product development and commercialisation.

 — Holdable Devices: Making Our Phones Good for Our Brains


Behind the benefits that smartphones bring to 3.5 billion people worldwide, lie subtle threats to our brains. Advertising-based apps exploit vulnerabilities in the human psyche to maximise engagement and sell more of their users’ attention to marketers. The ubiquity of such products has led to widespread behavioural addiction and lower attention spans, productivity, and quality of in-person conversations.

Knowing an activity conflicts with personal goals and values, as does half of Americans' media use, may not suffice to self-regulate: 40% of UK adults think they spend too much time online, 60% consider themselves ‘hooked’ and 33% find disconnecting difficult. Lacking impulse control, children and teenagers are even more vulnerable.

Current 'screen time' solutions are predominantly digital and rely on quantifying and blocking app usage, but guilt is an unsustainable motivation and different types of experiences may occur on the same platform. For example, while active engagement with real-life peers on social media has benefits comparable to offline interactions, passive consumption of content can undermine life satisfaction, emotional wellbeing and mindfulness. An effective intervention must, therefore, tackle the experiences that make phones and social media addictive regardless of which apps they occur on.

 — Holdable Devices: Making Our Phones Good for Our Brains
Social impact of products designed to maximise engagement.

Interaction Design

Drawing analogies between multidisciplinary literature and field observations, and interviews resulted in a profound understanding of the causes of problematic habits.

The underlying cause of compulsive use is the inhibition of our reflective mind. Social and micro-targeted content loads faster than our reflective brain thinks, and continuously arouses our mind, overwhelming our sense of sight and our reptilian brain, while depriving other senses and altering our perception of object permanence and time. Moreover, our brain seeks emotional homeostasis and needs external interruptions or strong willpower to change attentional states.

With our reflective brain off and our posture hunched, however, our willpower is weak. So, we scroll for more content on bottomless feeds that reward our actions with variable amounts of dopamine, like slot machines. We’re in a state of immersed flow until another event stimulates us enough to snap out of it, but withdrawal from all that dopamine may make us soon rush back to the phone.

Holdable devices offer platform-agnostic support through biofeedback-based, multimodal interventions that gently induce mindful attention awareness when using the phone on 'automatic pilot'. Users then effortlessly reawaken their reflective brain and consciously decide what to engage with. A spectrum of personas was defined from primary research findings. Their needs guided the definition of essential touchpoints.

 — Holdable Devices: Making Our Phones Good for Our Brains
Factors leading to unhealthy smartphone use.

Sensing and Signal Processing

Mutual capacitance changes reflect the motion between the hand and the phone and were sensed with off-the-shelf components.

Use cases were accurately inferred from mutual capacitance data using a confidential process pipeline.


The device combines vibration and large movements to stimulate all of the hand’s mechanoreceptors. Changes in sensory stimuli induce sensory-motor awareness and, subsequently, mindfulness.

Shape memory alloys allow for big shape changes in thin form factors. A gentle haptic wave accompanies interventions, and users can feel pleasant or unpleasant pulses by touching the device. These reflect how addicted to the phone users have recently been.

 — Holdable Devices: Making Our Phones Good for Our Brains
Actuation in interventions (top) and visualisations (bottom).

Power Management

High-discharge Li-Po batteries provide enough current to actuate shape memory alloys through transistor switches. The system’s average discharge rate of 11mA guarantees 54.5 hours of continuous usage with a small 600mAh battery, removing the need to switch it on/off so the Holdable doesn’t miss any usage. Users with reverse wireless charging-enabled phones never have to charge the device.

 — Holdable Devices: Making Our Phones Good for Our Brains
Internal and wireless charging hardware.


Three stickers with the same functionality but slightly different value propositions were built to test the impact of design decisions on cognition, behaviour and desirability.

  1. A high-tech-looking device with a discreet cover to resemble a phone case. Its pulse gets stressed when you repeatedly use your phone compulsively;
  2. A more decorative accessory;
  3. A speculative concept representing the skin of the phone. Its touches reward you for using it compulsively and its pulse gets anxious if you don’t, exposing its intentions.
 — Holdable Devices: Making Our Phones Good for Our Brains
Embodiments for pilot study.


Combining user-centred design, positive psychology, HCI and engineering methodologies resulted in the development of Holdable devices and a proposed paradigm shift in PSU interventions. Contrary to currently available software solutions, Holdables don’t surveil or judge users’ actions but focus on the quality of fundamental cognitive and behavioural processes. Their interventions tackle the underlying motivators of PSU and offer platform-agnostic support by gently inducing mindful attention awareness in moments of unplanned, inattentive behaviour, and by promoting compassionate self-reflection about one’s dysfunctional habits through non-quantified visualisations.

A mixed-methods approach evaluated the prototypes’ impact as psychological interventions, their touchpoints’ appropriateness and their desirability. Preliminary evidence validates the product’s benefits on user autonomy and mindfulness during smartphone use, and a very positive social impact. Tactile stimuli empowered users to effortlessly self-regulate, and the TUI’s sensing and actuation were perceived as intimate and non-invasive. Qualitative insights allowed a broad evaluation of design decisions and features that informed further development opportunities, value propositions, and empirical validation procedures. Engagement of currently underserved users is encouraging and insights indicate that achieving smaller form factors while more finely tailoring different Holdables to different consumer attitudes and demographics can fulfil the device’s potential as a widely accessible intervention. Further design development will then naturally extend Holdables into accessories for emerging wearable and immersive technologies.


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