Post by William J Williams, Product Lead
I am often asked why keep changing the Arclight when it already works.
It is a fair question. Used in more than 60 countries, the basic format has proved itself over many years. The easy route would be to add features simply to have something new to advertise. We try to do the opposite: keep what works and change only what earns its place.
Listening to user feedback
Two points kept coming back from users.
First, an Arclight kept in a clinic drawer, teaching kit or emergency bag should still switch on when suddenly needed. An instrument can be optically excellent, but if it has quietly gone flat at the bottom of a bag it is not much use.
Second, charging should be simple. USB-C chargers are now everywhere, yet earlier versions could leave users hunting for an older power source or the right cable.
These are modest changes, but such details often decide whether equipment is trusted, carried and actually used.
Improving charge retention
The biggest electrical change is what the Mk5 does when it appears to be doing nothing.
Earlier versions drew a small but continuous standby current. Over weeks and months, even this added up. The Mk5 now has true deep-sleep circuitry, reducing the drain to almost nothing, so natural battery self-discharge becomes the main limit.
Long-term, real-time storage tests continue — there is no substitute for simply waiting — but early results point towards storage times measured in years rather than months.
Simplifying USB-C charging
Arclight PCB highlighting the USB-C port
The Mk5 does not need fast charging. It simply recognises an ordinary USB-C supply and charges safely at the rate the battery requires.
It can therefore now use common phone, tablet and laptop chargers, as well as older USB supplies — one less special cable to lose.
From customer feedback to production
Every piece of customer feedback is reviewed as part of our ISO 13485 quality management system. A suggestion cannot simply be bolted onto the next batch. It becomes a design requirement, with risks and pass criteria set in advance.
Prototypes were tried with different power sources, storage current measured and normal operation checked before drawings, assembly instructions and inspections were updated for production. The first production lot was then inspected and tested to confirm the manufactured devices met the same requirements before being released.
It may sound dry, but it stops 'improvement' becoming guesswork. A clever circuit is useful only if it solves the original problem, is consistent and still works on the thousandth unit.
Continuous improvement, not reinvention
Breakdown of the internal components of the Arclight
Externally, the Mk5 is deliberately familiar: thin, light, solar-powered and free of bulbs or routine consumables. We have not added a screen, menu or pile of parts. The best new features are often those users barely notice because they simply remove a problem.
We have never treated the Arclight as finished. Each version makes the same core tool smaller, tougher, easier to use and more dependable. The Mk5 follows that line: listen, measure, simplify and improve.
Useful beats flashy every time. For us, that's what good medical device design looks like.