April 29, 2015 -
Some users of Apple Watch have reported on YouTube and Reddit that the device does not work properly if you have a wrist tattoo, as the ink seems to interfere with the smartwatch’s infrared sensors that enable wrist detection, according to a report by Business Insider.
The Apple Watch’s sensors are designed to automatically detect whether the smartwatch is on a person’s wrist, as well as access heartbeat-tracking capabilities and Apple Pay.
As a result, an individual’s wrist tattoos may prevent these features from working.
Reddit commenter “guinne55fan” said he thought his Apple Watch was defective until he “decided to try holding it against my [un-tattooed] hand and it worked … Once I put it back on the area that is tattooed with black ink the watch would automatically lock again.”
Meanwhile, YouTube user Michael Lovell posted a video demonstrating the issue.
The smartwatch appears to work fine on his untattooed left wrist, but the device fails to work and asks for his passcode when he attempts to use it while on his tattooed right wrist.
Tech blog iMore tested the device on a number of different individuals with tattoos and found that the sensor readings “varied wildly depending on colours and shading.”
The Apple Watch seemed to work fine with lighter shades, but had issues when being applied to wrists with tattoos that featured big, block dark colors.
However, the smartwatch works fine on those individuals with darker skin tones because “natural skin pigmentation doesn’t block light the same way artificial ink pigment or even scar tissue does,” iMore writes.
Apple Watch users can disable the wrist detection feature so they won’t be required to enter a passcode, however, this will make the smartwatch less secure.
On a related note, Valencell’s PerformTek biometric sensor technology is able to accurately measure biometric data such as blood flow, in any form-factor and under any condition, including on individuals with tattoos.
The company recently identified how to use multiple wavelengths at the wrist for the most accurate signal for measuring biometric data.
The Scosche Rhythm+, which is powered by Valencell’s PerformTek biometric sensor technology, uses both green and yellow light to measure at the arm and wrist.
The yellow light can successfully penetrate through tattoos to generate accurate readings, said Valencell.