Context

The AED (Automated External Defibrillator) design has remained largely unchanged for several decades. Heart Restart puts control back in the hands of the user, enabling people at risk of a cardiac arrest to carry a life-saving device with them everywhere they go.

I was responsible for the interface design of the device, ensuring it was intuitive to use. I also directed and edited the concept video.

Problem

Solution

Heart Restart challenges the status quo of defibrillators being publicly owned objects dispersed throughout the city and puts control back in the hands of the individual.

The primary goal of the defibrillator redesign is to be accessible; user-friendly, portable, and affordable.

Impact

We streamlined the defibrillation process by reducing the number of steps from an average of 22 to just 8. Each step was designed with accessibility in mind, incorporating both visual and audio guidance, including animated instructions to support users with varying literacy levels and those without medical training. By simplifying navigation and eliminating unnecessary steps, we significantly improved usability and response efficiency.

As a result, we successfully reduced the time to defibrillation from 10 minutes to just 1 minute, dramatically increasing the likelihood of survival in emergency situations.

Heart Restart can retail at £718, which is on the lower end of the defibrillator market (current defibrillators cost £900-1800).

Identifying the gap - the insight

Through a combination of user and professional interviews, market analysis, and early usability testing, we identified a significant gap in the AED market: the absence of a portable, affordable, and intuitive device designed specifically for laypeople. This insight became the foundation for our design direction, aiming to make life-saving technology more accessible to everyday users.

Medical Professional Interviews

• Switched focus to London, where ambulance response times average 11 minutes, compared to under 8 minutes in rural areas like Orkney.
• Medical professionals unanimously agreed: "The more defibrillators, the better."

Street Interviews

• Most people don’t know where the nearest AED is located.
• The public underestimates AED costs (guess £1,000 but existing AED's are on average £3,000). Would be willing to pay around £500, at a more affordable price point.
• Some would consider purchasing an AED as a "good Samaritan" item.

Usability Testing Existing Products (Establish Baseline)

• Users experienced high stress, even in a non-emergency setting.
• Many struggled to locate visual cues and follow audio instructions properly.
• Common issues included incorrect CPR technique, uncertainty, and lack of control over instruction pacing.
• Average time to defibrillation was 3-5 minutes.

Secondary Research (CPR & AED Accessibility)

• Only 5% of the UK population is trained and willing to perform CPR.
• 80% of cardiac arrests happen at home, and half are witnessed.
• Survival rate drops by 10% per minute without intervention—3 minutes is the critical window.
• Even in AED-dense areas of London, the nearest public AED takes 10 minutes to reach.
• Women are 27% less likely to receive CPR than men.
• No legal requirement for employers to provide AEDs in workplaces.

Market Analysis (AED Availability & Pricing)

• AEDs are primarily sold B2B, with prices ranging from £900-£1,800.
• The cheapest AED costs £450 (256 x 220 x 80 mm, 1.9kg).
• The smallest AED costs £2,880 (133 x 126 x 35 mm, 0.5kg).

Iterating - Physical and Digital Prototyping

Unlike public AEDs, which are large primarily for visibility—not due to complexity—we had the freedom to design a smaller, personal device. We quickly identified the smallest feasible form factor using open-source circuitry and existing component constraints, estimating the cost of electrical components at around £200 per unit.

Carry Test

Since our goal was to create an AED that people would carry with them daily, we needed to validate that behavior. We ran a week-long field test where two participants carried a prototype with them at all times, followed by in-depth interviews.

• Participants often left the device in a go-bag, indicating it was convenient—but not yet habitual.
• Form factor matters: the size may need to be reduced further to fit in pockets, especially for those who don’t typically carry bags.
• There is a critical need for an external indicator or tether—so that if the carrier experiences cardiac arrest, bystanders can easily locate and retrieve the device.

This feedback reinforced that portability, discoverability, and user habits must be central to both the physical and behavioral design of a personal AED.

Tether

Given that the AED was designed for portability, we incorporated a tether with an external tag that could be visibly displayed outside of a bag or pocket. This design choice ensures that in the event of a cardiac arrest, bystanders can quickly locate the device within the belongings of the individual experiencing the emergency. By enhancing the device’s visibility and accessibility, this feature increases the likelihood of timely intervention, ultimately improving survival outcomes in critical situations.

Interface Testing

We conducted 15 usability tests to observe how intuitively participants could use the device without any guidance or prompting.

• Static diagrams and verbal instructions used in existing AEDs were often confusing, leading us to consolidate animated, step-by-step visuals into a single screen for clarity.
• Clear diagrams significantly improved accuracy in both electrode pad and CPR hand placement.

Reflection

Talk to experts early

• Conversations with professionals in the field revealed insights we never would’ve found in academic papers or articles. These early discussions helped us course-correct and saved us significant time down the line.

Challenge with purpose

• Just because something has always been done a certain way doesn’t mean it’s the right way. It’s important to question the status quo—but equally important to test whether your alternative is truly better, not just different.

Test early, test often

• User testing consistently yielded valuable feedback we wouldn’t have uncovered through conceptual work alone. It not only surfaced pain points but also validated several of our design decisions. Time spent testing is never wasted—it’s where the most grounded insights emerge.