Aithre Illyrian Smart Pulse Oximeter

For full-time SpO2 monitoring, stick the Illyrian under the headset and let the app do the rest.


It took a high-altitude scare for Van’s‭ ‬RV-10‭ ‬builder and Aithre founder Jim‭ ‬Rutler to develop an interesting new‭ ‬product that allows for full-time SpO2‭‭ ‬monitoring and alerting‭. ‬SpO2‭ ‬is the‭ ‬shorthand way of describing oxygen saturation in the blood‭, ‬a good way to know‭ ‬if you need to add supplemental oxygen‭ ‬or to descend during high-altitude flying‭. ‬

The Illyrian‭, ‬which measures SpO2‭‭ ‬under the earlobe with a sensor that‭ ‬attaches to a headset earcup‭ (‬or the‭ ‬forehead with a sport wrap‭), ‬is a bold‭ ‬departure from traditional finger pulse-ox devices‭. ‬The Illyrian device got my attention while browsing the‭ ‬“innovations building”‭ ‬at last-year’s AirVenture because there has been a slow progression of gadgets for minding pilot and‭ ‬passenger health‭. ‬Sure‭, ‬finger pulse‭-‬ox devices get the job done‭, ‬but they don’t allow for full-time monitoring‭. ‬If you’re hypoxic‭, ‬you might not have the smarts to take a sampling‭, ‬plus there’s added workload when monitoring passengers‭. ‬The Illyrian sensor‭, ‬which uses a smartphone app for connecting with‭ ‬multiple sensors‭, ‬solves the problem‭. ‬I’ve been using the device for a couple of months‮—‬here’s a field report‭.‬

The Hardware

Need a quick review on pulse oximetry‭? ‬No matter how it’s packaged‭, ‬a sensor shines a visible red and an infrared beam of light‭ (‬through the finger or toe‭, ‬to name two bodily locations‭) ‬to detect the changes in color of the arterial blood‭. ‬Once the device computes‭, ‬it displays‭ ‬the measured blood oxygen saturation level on a display‭. ‬The Illyrian sensor is different only in that it measures below the earlobe or‭, ‬if you wish‭, ‬on the forehead while a sport headwrap keeps the sensor in place‭.‬

The main hardware consists of the‭ ‬SpO2‭‭ ‬sensor‭, ‬which has a built-in‭ ‬Bluetooth transmitter and antenna that sits in a small junction box on‭ ‬the bottom of the sensor’s cable‭. ‬That’s a good design because it keeps the transmitting antenna away from the head‭. ‬The‭ ‬sensor automatically pairs and streams‭ ‬the measured data to the smartphone‭ ‬without any user action‮—‬the whole idea behind the Illyrian‭.‬

The Illyrian works with the company’s useful Aithre Connect app for iOS devices, plus there’s compatibility with the Apple Watch.

Since the system needs battery voltage to operate‭, ‬it comes with a portable USB power bank‭, ‬though you can plug it in to a panel‭ ‬USB power port if you don’t want to deal with the power supply‭. ‬The‭ ‬power bank has minimal controls‮—‬a‭ ‬power button‭, ‬five battery life indicators and a handy flashlight function‭. ‬It’s charged via Micro-USB input and lasts a long time between charges‭. ‬I’ve been using it for a couple of months during my trials‭, ‬on a single charge‭. ‬Not any portable power bank will do since the Illyrian draws so little current some smart power banks will power off‭, ‬falsely sensing that nothing is connected‭. ‬There’s roughly 38‭ ‬inches of cable length to work with‭, ‬from the base of the sensor to the base of the USB connector on the other end‭,‬‭ ‬so keep that in mind if you plan to plug it into ship’s USB power‭.‬

Using It

Among pulse oximeters, we think the clinical-grade Masimo MightySat sets a standard for accuracy, and the Illyrian came close in performance.

I evaluated the device with my Bose‭ ‬A20‭ ‬headset‭, ‬and included is a coil cable wrap for keeping the sensor’s interface‭ ‬cable intertwined with the headset’s‭ ‬down cable‭. ‬These days I hate wired‭ ‬interfaces‭, ‬and this one is tolerable‮—‬barely‮—‬with the coil cable wrap‭. ‬I also evaluated the device with a Masimo‭ ‬MightySat‮—‬my go-to‭, ‬high-accuracy‭ ‬pulse oximeter I’ve learned to rely on in the airplane and also for endurance cycling training‭. ‬I also threw Garmin’s D2‭ ‬Delta PX aviator’s watch in the mix‭. ‬It has a wrist-based SpO2‭‭ ‬and heart-rate sensor built into the watch’s chassis‭. ‬What I’ve learned to like about it is its basic data display in the Garmin‭ ‬Pilot smartphone app‭, ‬but I’ve also‭ ‬learned to accept its measuring limitations‭. ‬The heart rate data lags‭, ‬and the SpO2‭‭ ‬measuring is finicky at best‮—‬accurate when it gets a clean sample‭, ‬which it doesn’t always get‭.‬

The Illyrian’s readings‭ (‬as measured under the earlobe‭) ‬were consistently close‭ ‬to the Masimo’s finger measurements‭. ‬Slapping the sensor on the forehead yielded good results‭, ‬too‭, ‬but admittedly not everyone will want to wear the headwrap to keep it in place‭. ‬One caveat‭, ‬says the company‭: ‬Women and children might get inconsistent readings below the earlobe and I couldn’t substantiate this so far in my trials when passing it around the cabin‭.‬

Garmin’s $1249 D2 Delta PX aviator’s watch (left) has a built-in wrist-based pulse oximeter (right) and heart rate sensor, but it has accuracy limitations. It’s more accurate when it gets a “clean sample,” but that isn’t always the case.

A Decent App

The Connect app has useful trend and accuracy data, but we’re waiting for third-party app compatibility.

You monitor SpO2‭‭ ‬on the Aithre Connect smartphone app‭, ‬which is refreshingly simple and has a shallow menu structure‭. ‬The Aithre‭ ‬Connect app can simultaneously connect with up to six Illyrian oximeters‭ (‬that’s a huge workload reducer when flying high with passengers‭), ‬and at press time the company was offering a 50%‭ ‬discount for a second oximeter‭. ‬I like that the Aithre Connect app notes the sampling quality of the SpO2‭‭ ‬and blood pressure readings below the displayed values‭. ‬That means if you get a reading that doesn’t quite look right‭, ‬you can dismiss it as a bum sample‮—‬and then adjust the sensor‭. ‬

You start by turning the Apple Siri/popup notifications on in the app‭. ‬For alerting‭, ‬the default warnings trigger when the SpO2‭‭ ‬drops below 92%‭ ‬and then again below 85%‮—‬which is indeed‭ ‬hypoxic‭. ‬You can also specify custom‭ ‬SpO2‭‭ ‬warning levels within the Settings tab of the app‭. ‬But the app falls short in that the warnings are provided only once‭, ‬“so as to avoid them being a nuisance‭,‬”‭ ‬says the instructions manual‭. ‬I think that should be user-controlled and the company says it is working on that in a future release‭.‬

The Illyrian can transmit to and display on some Experimental displays. That’s the Garmin G3X Touch.

The app has an easy to decipher time-trend‭ (‬up to 12‭ ‬hours‭) ‬graph for SpO2‭‭ ‬and heart rate that’s overlaid against pressure altitude‭. ‬The app is also interactive‭, ‬offering regular hypoxia risk testing with custom interval quizzes‭. ‬Wear an Apple Watch‭? ‬It’ll come in‭ ‬handy with this device‭. ‬The Aithre‭ ‬Connect iOS app includes a companion WatchOS app that tags along with the free download‭. ‬It’s installed automatically on the Apple Watch once the iOS device downloads the Connect app‭. ‬In turn‭, ‬the WatchOS app will display the SpO2‭‭ ‬and blood pressure automatically when the Illyrian is paired with the main iOS device‭. ‬I don’t use an Apple Watch but for those who do‭, ‬I think it will be more‭ ‬convenient than keeping the Aithre‭ ‬Connect app open all the time to monitor the biometrics data‭, ‬though the app does work in the background‭. ‬It doesn’t work with third-party apps and I’d like to see an interface with ForeFlight‭, ‬Garmin Pilot and the Seattle FlyQ app‭, ‬to name a few‭. ‬

Speaking of third-party systems‭, ‬the‭ ‬company at AirVenture was showing‭ ‬an onscreen biometrics interface with a Garmin G3X Touch display and an Advanced Flight Systems display‭. ‬The‭ ‬interface uses the Aithre Shield EX‭ ‬3.0‮—‬a device that’s integral to the company’s carbon monoxide and oxygen-tank pressure measuring systems‭, ‬which also display on the Aithre Connect app‭. ‬We’ll‭ ‬look at these worthwhile devices and‭ ‬their interfaces in a later issue‭.‬

Note the size of the Aithre’s pulse-ox sensor compared to the earcup of a Bose A20 headset. It’s reasonably unobtrusive and more convenient than a finger sensor.

Fair Price, Good Performer

These are my surface observations after‭ ‬using the Illyrian and the accompanying app‭. ‬Priced at‭ $‬169‭ ‬and now distributed by Sporty’s‭, ‬Aircraft Spruce and Pilot Mall‭, ‬to name a few‭, ‬the device is simple and simplifies the chore of keeping tabs‭ ‬on your‭ (‬and passengers’‭) ‬SpO2‭‭ ‬levels‭. ‬Company founder Jim Rutler saw that exact need firsthand when he and his passengers ran out of oxygen in his RV-10‭ ‬on a high-flying trip‭, ‬something that could have ended with an NTSB‭ ‬report‭. ‬“In my RV‭, ‬I have so many‭ ‬advanced avionics including synthetic vision‭, ‬I can precisely measure parameters down to the exhaust temperature in a cylinder and I have multiple ways‭ ‬to look at fuel flow‭, ‬but on that one‭ ‬passenger-carrying trip I couldn’t effectively monitor the O2‭ ‬supply and everyone’s blood-oxygen levels‭,‬”‭ ‬Rutler said‭. ‬Warts and all‭, ‬I think his Illyrian full-time pulse ox monitoring system is just the right backstop‭.

For more information, contact Aithre Aviation at 208-481-8310, or visit

Photos: Larry Anglisano and courtesy of the manufacturer.


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