Showing pulse oximeter and color sensor combining to measure oxygen in blood and skin tone

Perfecting The Pulse Oximeter

August 7, 2023 by Orlando Hoilett 28 Comments

We’re always looking for interesting biohacks here on Hackaday, and this new research article describing a calibrated pulse oximeter for different skin tones really caught our attention.

Pulse oximeters are handy little instruments that measure your blood oxygen saturation using photoplethysmography (PPG) and are a topic we’re no strangers to here at Hackaday. Given PPG is an optical technique, it stands to reason that its accuracy could be significantly affected by skin tone and that has been a major topic of discussion recently in the medical field. Given the noted issues with pulse oximeter accuracy, these researchers endeavored to create a better pulse oximeter by quantifying skin pigmentation and using that data to offset errors in the pulse oximeter measurements. A slick idea, but we think their results leave a lot to be desired.

Their idea sounds pretty straightforward enough. They created their own hardware to measure blood oxygen saturation, a smartwatch that includes red and infrared (IR) light-emitting diodes (LED) to illuminate the tissue just below the surface of the skin, and a photosensor for measuring the amount of light that reflects off the skin. But in addition to the standard pulse oximeter hardware, they also include a TCS34725 color sensor to quantify the user’s skin tone.

So what’s the issue? Well, the researchers mentioned calibrating their color sensor to a standard commercially-available dermatology instrument just to make sure their skin pigmentation values match a gold standard, but we can’t find that data, making it a bit hard to evaluate how accurate their color sensor actually is. That’s pretty crucial to their entire premise. And ultimately, their corrected blood oxygen values don’t really seem terribly promising either. For one individual, they reduced their error from 5.44% to 0.82% which seems great! But for another user, their error actually increases from 0.99% to 6.41%. Not so great. Is the problem in their color sensor calibration? Could be.

We know from personal experience that pulse oximeters are hard, so we applaud their efforts in tackling a major problem. Maybe the Hackaday community could help them out?

Mergers And Acquisitions: Analog Devices Snaps Up Maxim Integrated For $21 B

July 13, 2020 by Mike Szczys 25 Comments

Analog Devices will acquire Maxim Integrated for $20.9 billion dollars in stock, as reported by Bloomberg this morning.

Perhaps the confusing part of the news is that the Bloomberg article mentions the acquisition will let Analog Devices better compete with Texas Instruments. Wait, didn’t Texas Instruments acquire Maxim back in 2015? Actually, no. There were rumors (reported then by Bloomberg) that TI was nearing an acquisition deal but it fell through in January of 2016.

You may remember that Analog Devices snapped up Linear Tech in a $30 B acquisition back in 2017. Considering this morning’s news, how will they compare to the might of TI? Looks like 2019 revenue for TI was $14.38 B while Analog reported $5.99 B. Add in Maxim’s revenue of $3.1 B and there’s still a David and Goliath scenario here. Although revenue doesn’t tell the whole story and the proverbial slingshot for Analog may be its existing portfolio of high-margin devices, grown even larger with this acquisition.

Considering how the last half decade played out, this might mark the beginning of another wild cycle of mergers and acquisitions. The consolidation trend continues as we approach a world where just a few gigantic semiconductor companies turn production lines up to eleven to fill the world’s insatiable appetite for more powerful electronics (and more electronics in general).