GUVA-S12SD UV Sensor Module

Analog UV light-to-voltage converter for measuring the intensity of UV light.

The GUVA-S12SD UV sensor module is used for detecting the intensity of ultraviolet radiation. This module has an analog output that changes with the intensity of UV light.

PACKAGE INCLUDES:

• GUVA-S12SD UV light sensor module
• 3-pin male header

MAIN FEATURES:

• Detects UV light in the range of 240nm – 370nm
• Analog output voltage proportional to the UV index of UV light falling on the detector
• 3.3 and 5V compatible
• The GUVA-S12SD is a true UV detector that only detects light from 240 nm to 370 nm, the UV-B and most of the UV-A spectrum. It also picks up the upper end of the UV-C. GUVA-S12SD Responsivity Graph on

The UVC wavelengths are used in blacklights, tanning beds, reptile UV lamps, germicidal sterilizers, and similar applications. This module can be used to monitor the operation of those devices.

It can also be used to measure the UV index, which provides a scale to determine how intense the UV sun is and thus what protective measures should be taken.

The UV index scale is published by the EPA and is intended to give people advice on sun exposure and what protective measures to take to minimize sun damage.

SIG or SIO = Signal output – Connect to MCU analog input
GND = ground
VCC = 2.7V to 5.5V. Connect to Vcc of the MCU (usually 3.3 or 5V)
Module mounting
The module comes with the male header strip loose. The header can be soldered to the top or bottom of the module depending on the intended use, or wires can be used to make the connections.

For breadboard use, we place the headers on the bottom. Soldering is easiest if the header is inserted into a solderless breadboard to hold it in place during the soldering process.

How the GUVA-S12SD UV Sensor Module Works

The module contains an LM358 dual op-amp that converts the current output of the sensor into a voltage and then amplifies that output so it can be read by the analog input on an MCU for taking UV measurements.

The first stage op-amp provides a voltage proportional to the photocurrent of 4.3 * sensor in µA. If the photocurrent is 0.1 µA (0.09 mW/cm^2), then the output is 0.43 V

This feeds a second stage op-amp with an additional gain of 6.1x. In this example, the final output is 0.43V x 6.1 = 2.62V.

As configured, the module is especially useful for measuring moderate to moderately high UV light levels or if the sensor is placed behind a neutral density filter to reduce the percentage of UV falling on the sensor.

If it is desired to measure very high UV levels, the second amplification stage can be bypassed. This can be achieved by shorting the 5.1K resistor "512" and removing the 1K resistor to its right marked "01B" or "102". This changes the gain of the output amplifier to x1, effectively removing it from the circuit. With that modification, the UV index is then calculated by multiplying the output by 10.

Note: as of 6/2021, we are modifying this module and it now comes with a 1M feedback resistor on the first stage, as mentioned above. Before that date, the feedback resistor was 10M. 10M resistors are marked with 01F, 1M resistors are marked with 01E. With a 10M feedback resistor, the first stage is 43 * sensor photocurrent in µA. If the photocurrent is 0.1 µA (0.09 mW/cm^2), then the output is 4.3 V.