A UV Meter For The Flipper Zero

May 19, 2025 by Matt Varian 6 Comments

We all know UV radiation for its contributions to getting sunburned after a long day outside, but were you aware there are several types different types of UV rays at play? [Michael] has come up with a Flipper Zero add on board and app to measure these three types of radiation, and explained some of the nuances he learned about measuring UV along the way.

At the heart of this project is an AS7331 sensor, it can measure the UV-A, UV-B, and UV-C radiation values that the Flipper Zero reads via I2C. While first using this chip he realized to read these values is more complex than just querying the right register, and by the end of this project he’d written his own AS7331 library to help retrieve these values. There was also a some experimenting with different GUI designs for the app, the Flipper Zero screen is only 128x64px and he had a lot of data to display. One feature we really enjoyed was the addition of the wiring guide to the app, if you install this Flipper Zero app and have just the AS7331 sensor on hand you’ll know how to hook it up. However if you want he also has provided the design files for a PCB that just plugs into the top of the Flipper Zero.

Head over to his site to check out all the details of this Flipper Zero project, and to learn more about the different types of UV radiation. Also be sure to let us know about any of your Flipper Zero projects.

An Exceptionally Small UV Sensor

May 2, 2015 by Brian Benchoff 7 Comments

Most of the hacks we see hitting the tip line are exactly that – hacked up hardware projects held together with hot glue and duct tape. [x-labs]’ entry for the 2015 Hackaday Prize, the UV badge, is certainly not one of these projects. It’s a professional one-off, capable of displaying the UV index, temperature, humidity, and pressure in one tiny little enclosure.

The UV badge is designed to be used outdoors. This means any old display ripped from a Nokia phone won’t do; that will wash out in the sun. Instead, [x-labs] is using a very sunlight-readable Sharp Memory LCD. A nice choice, as it’s an exceptionally low-power device.

Inside the 54 x 34 x 7.1 mm 3D printed enclosure is a very thin PCB, and all surface-mount components. The device is powered by a single coin cell battery that should give months of run time.

With a product designed so well, we’re wondering if the UV badge will be in the running for the Best Product category of the Hackaday Prize this year. There aren’t many projects in the running, and the winner gets a enough funding, machinery, and experience to turn their project into a product.

The 2015 Hackaday Prize is sponsored by:

Hats With Sunblock Reminders Are Easy To Make

July 26, 2014 by Matt Terndrup 14 Comments

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Just about anyone can build this UV index sensing wearable that detects heat rays from the sun and reminds the user to put on sunscreen. There is no soldering required, which makes this a nice beginners projects for those unfamiliar with hooking up electronic sensors.

All that is needed is a FLORA main board, one UV index sensor, a piezo Buzzer, a 500mAh lipoly battery, 2-ply conductive thread, a couple of household tools, and your favorite summer’s hat.

Once the materials have been rounded up, the rest of the process is relatively simple. Threading the FLORA in and place and connecting the Piezo only takes a few minutes. Then the UV sensor is added allowing the hat to start collecting data. A little bit of coding later, and the whole system is ready to be worn out in the sun.

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What’s great about this project is that the hat can be programmed to play a song when it is time to apply more sunscreen. Everyone from beach bums, to sun-bathing beauties, to music festival attendees will be able to find this hat useful. And, it is cheap and easy to make.

The video on the Adafruit tutorial page shows how simple it is to rig up the system.

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