This little sensor is a great way to add UV light sensing to any microcontroller project. The VEML6070 from Vishay has a true UV A light sensor and an I2C-controlled ADC that will take readings and integrate them for you over ~60ms to 500ms.

Unlike the Si1145, this sensor will not give you UV Index readings. However, the Si1145 does UV Index approximations based on light level not true UV sensing. The VEML6070 in contrast does have a real light sensor in the UV spectrum. It's also got a much much simpler I2C interface so you can run it on the smallest microcontrollers with ease.

Unlike the GUVA analog sensor, the biasing and ADC is all internal so you don't need an ADC.

This UV sensor works great with 3 or 5V power or logic, its nice and compact, and its easy to use with any I2C-capable microcontroller. Each order comes with one assembled PCB with a sensor, some handy pullup resistors, a 270K rset resistor and a small piece of header. Some light soldering is required to attach the header but its a fast task!

Check out our tutorial for details on on how to use this sensor, including files, code and assembly!

The TSL2561 luminosity sensor is an advanced digital light sensor, ideal for use in a wide range of light situations. Compared to low cost CdS cells, this sensor is more precise, allowing for exact lux calculations and can be configured for different gain/timing ranges to detect light ranges from up to 0.1 - 40,000+ Lux on the fly. The best part of this sensor is that it contains both infrared and full spectrum diodes! That means you can separately measure infrared, full-spectrum or human-visible light. Most sensors can only detect one or the other, which does not accurately represent what human eyes see (since we cannot perceive the IR light that is detected by most photo diodes)New! As of June 3, 2014 we are shipping a version with a 3.3V regulator and level shifting circuitry so it can be used with any 3-5V power/logic microcontroller.The sensor has a digital (i2c) interface. You can select one of three addresses so you can have up to three sensors on one board - each with a different i2c address. The built in ADC means you can use this with any microcontroller, even if it doesn't have analog inputs. The current draw is extremely low, so its great for low power data-logging systems. about 0.5mA when actively sensing, and less than 15 uA when in powerdown mode.Of course, we wouldn't leave you with a datasheet and a "good luck!" - we wrote a detailed tutorial showing how to wire up the sensor, use it with CircuitPython or Arduino and example code that gets readings and calculates lux

Upgrade a project that uses a photocell with the GA1A12S202 analog light sensor. Like a CdS photo-cell, the sensor does not require a microcontroller, the analog voltage output increases with the amount of light shining on the sensor face. This sensor has a lot of improvements that make it better for nearly any project.The biggest improvement over plain photocells is a true log-lin relationship with light levels. Most light sensors have a linear relationship with light levels, which means that they're not very sensitive to changes in darkened areas and 'max' out very easily when there's a lot of light. Sometimes you can tweak a resistor to make them better in dark or bright light but its hard to get good performance at both ends. This sensor is logarithmic over a large dynamic range of 3 to 55,000 Lux, so it has a lot of sensitivity at low light levels but is also nearly impossible to "max out" so you can use it indoors or outdoors without changing code or calibration. Since the sensor is fabricated on a chip, there are also fewer manufacturing variations, so you won't have to calibrate the sensor from one board to another.Using the sensor is easy as pie: connect the Vin to 2.3-6VDC, Gnd to ground and measure the analog output on OUT. It will range up to 3V (at extremely bright outdoor sunlight). On an Arduino, just use analogRead() with the OUT pin connected to an analog pin. For more information including graphs, power consumption, etc check out the datasheet in the Tech Details tab. On this breakout we placed a 68KΩ resistor from OUT to ground to turn the current into a voltage.

GA1A12S202 Log-scale Analog Light Sensor (6:52)

Your electronics can now see in dazzling color with this lovely color light sensor. We found the best color sensor on the market, the TCS34725, which has RGB and Clear light sensing elements. An IR blocking filter, integrated on-chip and localized to the color sensing photodiodes, minimizes the IR spectral component of the incoming light and allows color measurements to be made accurately. The filter means you'll get much truer color than most sensors, since humans don't see IR. The sensor also has an incredible 3,800,000:1 dynamic range with adjustable integration time and gain so it is suited for use behind darkened glass.We add supporting circuitry as well, such as a 3.3V regulator so you can power the breakout with 3-5VDC safely and level shifting for the I2C pins so they can be used with 3.3V or 5V logic. Finally, we specified a nice neutral 4150°K temperature LED with a MOSFET driver onboard to illuminate what you're trying to sense. The LED can be easily turned on or off by any logic level output.Connect to any microcontroller with I2C and our example code will quickly get you going with 4 channel readings. We include some example code to detect light lux and temperature that we snagged from the eval board software.A detailed tutorial is here, check out our Arduino library and follow our tutorial to install. Wire up the sensor by connecting VDD to 3-5VDC, Ground to common ground, SCL to I2C Clock and SDA to I2C Data on your Arduino. Restart the IDE and select the example sketch and start putting all your favorite fruit next to the sensor element!

RGB Color Sensor with IR filter - TCS34725 (19:36)

Remember when you were a kid and there was a birthday party at the pool and your parents totally embarrassed you by slathering you all over with sunscreen and you were all "MOM I HAVE ENOUGH SUNSCREEN" and she wouldn't listen? Well, if you had this UV Index sensor connected up to an Arduino you could have said "According to this calibrated SI1145 sensor from SiLabs, the UV index right now is 4.5 which means I do not need more sunscreen" and she would have been so impressed with your project that you could have spent more time splashing around.

The SI1145 is a new sensor from SiLabs with a calibrated light sensing algorithm that can calculate UV Index. It doesn't contain an actual UV sensing element, instead it approximates it based on visible & IR light from the sun. We took this outside a couple days and compared the calculated UV index with the news-reported index and found it was very accurate! It's a digital sensor that works over I2C so just about any microcontroller can use it. The sensor also has individual visible and IR sensing elements so you can measure just about any kind of light - we only wrote our library to printout the 'counts' rather than the calculate the exact values of IR and Visible light so if you need precision Lux measurement check out the TSL2561. If you're feeling really advanced, you can connect up an IR LED to the LED pin and use the basic proximity sensor capability that is in the SI1145 as well.

We wrapped this nice little sensor up on a PCB with level shifting and regulation circuitry so you can safely use it with 3 or 5V microcontrollers. If you are using an Arduino, we've got a lovely tutorial and library already written up with example code so you can quickly read sensor readings and the UV index in under 10 minutes. Each order comes with one fully assembled and tested PCB breakout and a small piece of header. You'll need to solder the header onto the PCB but it's fairly easy and takes only a few minutes even for a beginner.