Grogu said:
ThunderBird said:
Next year marks my last year in engineering, and I'll need to begin a finished project for my capstone design course. This hands me a rare chance to pour an absurd amount of time, money, and effort into building something impressive from scratch. At the moment, I'm considering designing an injector pen that's improved and more tailored to what a typical peptide user actually needs, rather than being built for insulin delivery. The Novo Nordisk Echo sparked this idea for me—it's somewhat smart, but its electronics are just so-so in my view. Given how small chips and electronics have become these days, it seems like it ought to be capable of FAR more.
So here's my question: if you could have a pen with XYZ features, doing XYZ things, what would you want it to do, and why?
A few items I already intend to show on the pen are listed below:
Substance - Total initial amount
Dose - total dose left
Dosing Schedule
Date/Time + Date Reconned / however days old the pep is
Previous Dose
Time till next Dose
Other things you might want could include:
form Factor
general aesthetics
needles ( hidden or shown)
how you chose the dose
smartphone connectivity
Alarms
Cartridge loading and compatibility
Material/build quality
Thanks for sticking with this long post. If you've got any ideas you'd like to share, please go ahead and put them here—I'll read every reply in this thread.
Just to be clear, I have no plans to bring anything to market; I don't have the CAPX for a project like that. More likely, I'll share Code/CAD/manufacturing process once everything is finished, if this ends up being the project I pursue.
For my part, one improvement would be knowing more precisely how much peptide remains in the cartridge. A few of my pens have markings on the cartridge holder, yet those markings are meaningless to me. Sure, I could consult the instructions, but finding the time is another matter...

On top of that, certain pens arrived without any paperwork.
Priming is another annoyance. I believed I had removed every bit of air from a cartridge I'm using now, but when I checked yesterday, air was still present. Whether any engineering solution exists for that, I can't say.
Since I won't keep the pen needle attached between doses, I'd rather have pens that are more compact. I get that cartridge length and the length of the "plunger" set the size, but any way to make these pens slimmer and shorter would be welcome.
There's one more frustration: at the moment I use the Savvio. The build quality is great, its smaller size is great, but the cartridge loading mechanism is not. Screw-in cartridge holders are what I prefer, whereas the Savvio relies on a spring mechanism that rotates the same direction as when you take off a needle. As a result, while removing a needle, I've had the cart holder pop out several times by accident. A spring loaded cart holder sounds appealing, but perhaps the threading should have gone the opposite way?
Ergonomics deserve thought too. A design that made one-handed use easier, particularly for those with arthritis, could be worth designing around. I don't have that (yet), but I can imagine it becoming a problem.
Last, even though I like pens and have tested dosing many times, I still find myself unsure whether the dose actually went in. I don't know if there's a way to engineer something for that.