PCE-UV34 UVA/UVB Radiation Meter

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how to use measure uvb output tester.

We all love the sun and, of course, we know the damage of ultraviolet radiation to human skin. Obviously, you can’t tan on a beach for long. But it’s not obvious, can you walk in the sun in a T-shirt and swim, walk in the mountains? After the next «burning» of the sun in the mountains on the Red Glade the question arose - how to measure the instant index of ultraviolet radiation and know when to hide in the shadows. As a result, this small instrument, the UV sensor, was born with a number of additional functions.

How to use measure uv intensity.

The main function is to measure the UV radiation index. In addition, it was necessary to measure the temperature of the air and the temperature of the water with an accuracy of at least 0.5 degrees (especially when bathing in a pool of ice water looked at the Chinese thermometer, which was floating there - 28 degrees, and was not nearby). And of course the battery power.

Main components: VEML6075 + MCP3421 + STM8

There are not many sensors available to measure the UV radiation index. The UV sensor of study is usually used - the phototransistor. But it turned out to be quite difficult to calibrate. The choice fell on the digital sensor, VEML6075. It turned out to be very good. The only drawback - difficult to buy, delivery had to wait for about a month through the official channels - «Fifth element» (China has not started to consider - in a single device to guess about quality unpleasant). Advantages of the sensor:

• light calibration at home
• Cosine response of the sensor surface - light drop
• Two-band exact index readings - UVA UVB
• low consumption
• I2C communication - fully digital sensor

Originally, the size of the sensor was 2x2 mm, there was no thermoffin, and I thought it would be hard to smell this little thing with a regular soldering iron - but it worked out great.

The second question, measuring the temperature of the water, solved with a thermocouple. To accurately capture data from this sensor, use a very precise ADC, with a built-in reference voltage source, MCP3421. 18-bit resolution + 8 multiple signal amplification for a K-type thermocouple gives 0.01 degree temperature resolution - more than enough. Given the need to measure the temperature of the compound, the precision was around 0.2 degrees. Checked by measuring boiling water and ice.

How to use measure uv c light.

As a microcontroller - the simplest and cheapest option - STM8S003F3. On board are all - timers, I2C - needed for the sensor, etc.

Because the instrument has to run on the sun - then as an indicator - the LCD screen. I wanted to be compact - I chose this:

The controls had to be tormented. Multiplexing LCD outputs on a regular microcontroller was a challenge, but it worked out great.

The body selected a small, compact from the company Sanhe model «20-31». External size - 35x45x18 mm. All fit - board, indicator and battery.

Scheme and board will not bring, everything is on github

Calibration of the UV sensor.

After receiving the readings from the sensor - they were not very happy, were not similar to the readings of the «hydromechcenter». I had to learn how to calibrate the sensor correctly.

Sunlight in its spectrum has UV radiation, IR radiation and visible radiation. To calculate the intensity of UV radiation, it is necessary to subtract excess data about IR radiation and visible radiation. In order to calculate the constants in the formula used, two artificial light sources are required in the sensor:

• A normal filament lamp that emits a spectrum and visible radiation into IR;

• LED lamp - it only emits visible radiation

When we get the sensor readings under these different light sources, we calculate the constants needed for the formula. And after that, the sensor got really good - the sunny-day readings coincided with the weather sites.

Experience in using

And when you make a sensor, you have to learn what UV radiation is, what it’s bad for. What kind of radiation it is. What it does to your skin. How the sun’s position affects the horizon and whether UV radiation is harmful to the eyes.

Personally checked all the articles about «burning». The sensor proved itself perfectly. Now, when I see a sensor in the mountains with a 13, I put on a tight shirt and I cover all the body parts. And in the evening, when the index is 5, I walk quietly and I’m under the warm rays of the sun.

How to measure uv index.

Learned that on a sunny day, one can burn well and in Moscow - the index reaches 9 at noon. And also, when you swim, the time spent in the sun doubles.
It’s been very useful to me, and I still use it, and the whole family trusts me. So I added a very precise humidity sensor, HTS221. It also runs on I2C, so I just made a mini handkerchief and I put it in. And I was using a wire that was lacquered with 0.15mm. So now it’s also showing humidity.