editor's blog
Subscribe Now

UV Index Sensor

Have you been out in the sun too long?

OK, yeah, not really the right time of year to ask that question north of the equator… Especially around here in the Northwest, under a thick blanket of puffy gray.

So the answer is probably, “No.” But, come springtime, you’re going to want to get all of that flesh exposed to suck up those rays it’s been missing during the Dark Months. So… how do you know how long to stay out? Other than the telltale pink that indicates you’re too late?

What if your wearable device could measure that for you? That’s the goal of a couple of new Silicon Labs optical sensors: the Si1132, combined with an ambient light sensor (ALS), and the Si1145/6/7 devices, which include and ALS, IR proximity detector, and one or more LED drivers. All in clear 2×2 mm2 packages.

To some extent, you might just say that this is just a photodetector that responds in the UV range. But you’d then look at the block diagram and notice that there’s no UV photodiode shown.

si1132-BD_reduced.png

I asked about that, and it turns out that their visible light detector also responds to UVA and UVB, and they use proprietary algorithms to extract the UV index from them. You could do the same thing today (if you had the algorithms), but you’d need to get a plain UV detector and do the index calculation yourself using separate devices. With these devices, it’s integrated, and what you read out is the pre-calculated index.

Note also that there’s nothing in that diagram for accumulating exposure. That’s because the device doesn’t actually do that; it just gives a real-time UV index reading that the system designer can accumulate to determine overall exposure.

The LED drivers in the Si1145/6/7 series are summarized as using the 1-LED version for motion detection, 2 LEDs for 2D gesture recognition, and 3 LEDs for 3D gesture recognition. The LEDs are driven under control of this device, while the device senses the response. It also has its own IR emitter for proximity checking.

Si114x-BD_reduced.png

You can find more information in their release.

Leave a Reply

featured blogs
Jan 17, 2022
Today's interview features Dajana Danilovic, an application engineer based near Munich, Germany. In this video, Dajana shares about her pathway to becoming an engineer, as well as the importance of... [[ Click on the title to access the full blog on the Cadence Community sit...
Jan 13, 2022
See what's behind the boom in AI applications and explore the advanced AI chip design tools and strategies enabling AI SoCs for HPC, healthcare, and more. The post The Ins and Outs of AI Chip Design appeared first on From Silicon To Software....
Jan 12, 2022
In addition to sporting a powerful processor and supporting Bluetooth wireless communications, Seeed's XIAO BLE Sense also boasts a microphone and a 6DOF IMU....

featured video

Synopsys & Samtec: Successful 112G PAM-4 System Interoperability

Sponsored by Synopsys

This Supercomputing Conference demo shows a seamless interoperability between Synopsys' DesignWare 112G Ethernet PHY IP and Samtec's NovaRay IO and cable assembly. The demo shows excellent performance, BER at 1e-08 and total insertion loss of 37dB. Synopsys and Samtec are enabling the industry with a complete 112G PAM-4 system, which is essential for high-performance computing.

Click here for more information about DesignWare Ethernet IP Solutions

featured paper

Add Authentication Security to Automotive Endpoints Using the 1-Wire Interface

Sponsored by Analog Devices

By adding a single authentication IC, automotive designers can authenticate a component with only one signal between an ECU and endpoint component. This is particularly important as counterfeit and theft are increasingly problems in automotive applications. This application note describes how to implement the DS28E40 Deep Cover 1-Wire Authenticator in a system to provide authentication for optical cameras, headlamps, EV Batteries, occupancy sensors, and even steering wheels, and more.

Click here to read more

featured chalk talk

IEC 62368-1 Overvoltage Requirements

Sponsored by Mouser Electronics and Littelfuse

Over-voltage protection is an often neglected and misunderstood part of system design. But often, otherwise well-engineered devices are brought down by over-voltage events. In this episode of Chalk Talk, Amelia Dalton chats with Todd Phillips of Littelfuse about the new IEC 623689-1 standard, what tests are included in the standard, and how the standard allows for greater safety and design flexibility.

Click here for more information about Littelfuse IEC 62368-1 Products