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Prepi hero with award.jpg

Project Duration

10 weeks

Project Partner

Jack Johnston



video direction/editing

internal mechanism

case design

prototype fabrication
CAD + rendering

Prepi Logo.png
A smart epinephrine autoinjector system
Iphone Mockup.png
Case + Pen.png

Severe allergies are rising in America


The percent increase of severe allergy diagnoses  between 2007 and 2016

1 in 10

American adults have a severe allergic reaction to some foods

There are 3 problems with current Epinephrine auto-injectors

(Hover over images for more information about them)

Logistics with paramedics 

"During a time of crisis,
humans are bad historians." 

They are too big

"The only time I needed my EpiPens, was when I didn't have them." 

Lack of Communication

"I wish I could know if my daughter is having an attack before getting a call from the hospital." 

EpiPen holds a monopoly on the market, stunting progress in the industry, and price gouging.




Alongside face to face interviews, we used anonymous online polling to get a broader audience 


Robustness vs. Connectivity

The reality of technology is that there are inevitable technical difficulties. It's also more costly for a one-use item, which is what we wanted to get away from. 
Because of this, it was vital to keep the electronics out of PREPI.

Flatter Form

Fits into pocket much better.

Emergency Services

Allows for communication and tracking features.

Pen Semantics

Common usage errors result in the user stabbing their thumb. Everyone knows how to work a pen, so we utilized this natural movement.
We continued with
The overall size 
The flat shape
The arrow indicating the needle end

We dropped
The safety living at the top
The wire frame clip 
Prototype Proof (dragged) 2_edited.jpg
Prototype Proof (dragged)

Pen semantics and flat forms followed through into our first prototype






1 Updated external housing design.
2 The safety cap design changed from clipping onto the internal housing (3), to mating into the external housing (1). This was a safety consideration so the cap does not accidentally set off the injector.
3 Internal housing contains the syringe + needle. These iterations were mostly space constraint struggles. Getting the thinnest possible final product while still using standard parts inside.
4 Final injector design. One PREPI is 25% shorter than an EpiPen.

Final form features

But we still had problems to solve

• How can we implement IoT without deadly technical difficulties?
• How can we make the smaller size plausible?
• How do we carry two at a time? 

The size issue

A large part of this project, for me especially, was to actually prove that our concept could realistically be as small as we made it.

We referenced a similar design created by mechanical engineering students at the University of Connecticut. From there, we were able to get standard parts that we knew were actually tested and would work. 
The main difference in our design is that our pen uses spring force to puncture the CO2 cartridge, while UConn's uses human force (which is unreliable).

How it works

Remove Cap

Implementing connectivity
and carrying two PREPIs

The case features a BLE (bluetooth low energy) module, temperature sensor, photoresistor, and a small battery. When PREPI is removed, the case sends a notification to the user's phone where they can access emergency services.
The temperature sensor is used in non-emergencies to alert the user when their PREPIs are getting too hot, since epinephrine degrades with heat and light.

Emergency Services

Background features

Magazine .jpg
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PREPI was featured in the 2019 December issue of Gray Magazine
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