I had fun in the sun with LogicInk's UV-sensing temporary tattoo

Can this sensor help you avoid dangerous UV rays?
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Skin cancer is one of the most common types of cancer, with over 5.4 million new cases each year in the US - so there's a good reason you should be slapping on that lotion when the sun is beating down.

LogicInk is hoping to show people just how damaging the sun can be with its new Logic UV temporary tattoo. On a warm San Francisco day in the middle of a heatwave, I trekked over to Logic's headquarters to get some hands-on time with the tattoo.

Read this: Temp tattoos will get us to invisibles

Does it actually work, and can it actually help you avoid damaging UV rays? Let's find out.

Shine on me

I had fun in the sun with LogicInk's UV-sensing temporary tattoo

Carlos Olguin, LogicInk's co-founder and CEO, handed me a small purple envelope. Inside of it was just a couple of materials: The Logic UV and some instructions. I slapped it on the backside of my hand and peeled the protective layer off.

Wearing it is a little like putting a sticker on your hand, and people are definitely not going to confuse this with an ink stamp or henna. There are two indicator rings in the middle, and the rest is clear. The inner ring is white and will turn various shades of purple in the sun. The outer ring is divided into three segments, and they will turn bright pink to let you know you've had your fill of sun for the day.

Olguin escorted me outside, and as I stepped into the shade just beyond the front door I looked at the tattoo. It turned to a light pink. There was no sun on me; I was in the shade, as was the tattoo. Yet the tattoo was telling me I was still absorbing UV rays. When you're going about your day, it's instinct to head for shade or shaded areas when the sun feels like it's going to melt off your skin. Usually, you feel safe and comforted - but, as the Logic UV showed me, you're still getting those UV rays. Olguin says that for many people this was a particularly surprising revelation during research, as they were constantly surprised by where they were touched by UV rays - even under an umbrella.

As I stepped into the sun directly, the inner ring got darker. Then, Olguin pulled out a trick. He gave me some sunscreen to lather directly to the Logic UV, advising me to apply it on only half of the tattoo. I went back into the shade and saw that it had become two-toned. The half with sunscreen was white, while the half without sunscreen was still pink.

Basically, the Logic UV is always telling you how much UV you're being exposed to, and it adjusts based on the elements. This works in the shade, in the water, in direct sunlight and even with sunscreen.

The outer ring tells you when you've had your fill in the day. I wasn't able to try this, as I didn't get to play with the Logic UV for a full day, but Olguin tells me it's dependent on your skin type. Each of the three segments corresponds to a different type, you see; The first segment is for fair skin, the second is for medium skin and the third is for dark skin.

In my time with it, the Logic UV was a breeze to use. It's simple to understand, with only glances at your hand telling you what you need to know. To create something so simple takes a lot of work, so how did it come together?

The most personal wearable

I had fun in the sun with LogicInk's UV-sensing temporary tattoo

When LogicInk was founded, the company believed the future of wearables would create a new space - one that has been popping up at research universities all over the world - wearable temporary tattoos.

"Yes, electronic wearables will continue to evolve, but there will also be a space where having wearables that the same UIs you see on your Apple Watch or your phone - activity bars or energy rings or whatever you have now - could be programmed not by electronics but by using chemistry or biology directly on a device that is on your skin," Carlos Olguin tells Wareable.

So while LogicInk was working on a host of different skin-based sensors, it looked around and decided to venture forth with an idea that had business opportunity, could be manufactured with ease and wouldn't run into federal regulations from the likes of the FDA. It settled on skin care, with a specific interest in UV rays.

Initially, this was all about the health angle - keeping people's skin healthy and helping them avoid skin cancer, but it soon found out there were other segments of people who wanted to keep track of UV rays on the skin. People who tan, for example, could use Logic UV to tell them when they're done so they don't over-tan. People who are afraid of aging of skin later in life could also use it to help reduce exposure.

As LogicInk was developing the UV, it started to dive into science like minimal erythema dose (MED), which is the amount of UV light a certain skin type can be exposed to. LogicInk's sensors are calibrated to those existing measurements. "We're not making things up," Olguin says.

The natural next step is to look at the different skin types, and the company looked at measures like the Fitzpatrick scale, which covers six variations of skin. The problem, however, is the more data and information LogicInk built into the Logic UV, the more test users were getting confused.

"Initially we started doing it very accurate but then we realized that users were overwhelmed by the fact that they don't even know what skin type they are," Olguin says. "We started to differentiate between UV A and UV B, which have different effects on your skin, but we also learned that was a bit overwhelming for users."

So the team kept it more simple. A small ring to tell you how exposed you are, and a large ring telling you when you've had your fill. While LogicInk isn't ready to talk about price yet - noting that it's still testing potential price points - the Logic UV is set to start shipping in early 2018.

The tattoo is designed for a day's use, though Olguin notes its adhesive and sensors will last for longer than that. It's also in discussions with possible partners on selling the Logic UV. For example, Olguin notes it would be cool if a dermatologist were to hand out Logic UVs like a dentist does floss during visits. Alternatively, imagine Ray Ban packing in the tattoos with sunglasses, or sunscreen makers packing it in with sunscreen.

The ultimate goal for LogicInk, however, is ultimate personalization. "That's our goal, that people really treat this as another form that tells something about themselves," Olguin says.

Eventually, this would include being able to create your own design, mixing and matching sensors for different conditions with different designs to create the best skin-based wearable for you. For example, LogicInk showed early prototypes that could sense alcohol, which would be able to tell you if you're impaired to drive. Other potential biological-based sensors include pollution sensors for air quality, diabetes and more.

The future for LogicInk is bright indeed, but users will have to get their fill on the Logic UV first.

How we test

Husain Sumra


Husain joined Wareable in 2017 as a member of our San Fransisco based team. Husain is a movies expert, and runs his own blog, and contributes to MacRumors.

He has spent hours in the world of virtual reality, getting eyes on Oculus Rift, HTC Vive and Samsung Gear VR. 

At Wareable, Husain's role is to investigate, report and write features and news about the wearable industry – from smartwatches and fitness trackers to health devices, virtual reality, augmented reality and more.

He writes buyers guides, how-to content, hardware reviews and more.

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