UV Sensor - UVM-30A wrong readings. Need help ASAP


I have been working on a project to detect when ARC from the welding aluminum process is ON and when it is OFF. The idea of the project is to track the productivity of the welding area. Arduino code is all set up and working fine, however, I am struggling with the UV sensor I got. I am using the UVM-30A Sensor that can detect the intensity of UV radiation (200~370nm). I don’t know why it is reading random values - when ARC is ON the sensor reads from 0 to 1V. It should only detect 0V when ARC is OFF. I don’t know why it reads small values when ARC is ON and seems so intense.

The temperature in the area is around 60 degrees Celsius.
The area has a lot of dust;
I have placed the sensor very close to the ARC;
The sensor stopped working after 3 days installation in the area.

Any tips??

Yes! Your work area has high intensity mercury vapor lights. My plant had them also and if the phosphor coating was old, lots of the UV got through. the usual remedy is to replace the lights with LED lights. More light, less power, no UV!

Hi Paul!

Thanks for your reply.
I won’t be able to do any changes in the area. I need to find a solution considering the actual environmental circustances. The problem is not the Lamps in the area, the problem is that even when ARC is ON the sensor reads 0V many times! When ARC is OFF, because of the lamps, I know the sensor will read some Voltage… and it is okay. The only thing I don’t wanna is the sensor to read 0V when ARC is ON and intense. How can I fix that?

What readings do you get when the sensor is not exposed to any light?

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Around 0V

What readings do you get when the sensor is exposed to direct sunlight?

Does ARC mean an arc? As in arc welding?
Arc welding puts out massive amounts of electrical interference, this is likely affecting
your sensor badly.

Hi @MarkT . Thats correct. Arc from the welding process. That could be a reason. I got two more sensors to test… a LDR module and a smoke module sensor… maybe they are more resistant to electrical interference. These things we only know by testing…

From what you describe, it seems like its working fine. From the graph in this reference sheet, the output signal will peak at 1.2V.

Maybe try the test code on that reference (note that it uses an analog input, not digital) and then take a look at the signal on the serial plotter.

Yes, I am using an Analog input (A0). I have checked this datasheet… what I dont understand is why it shows 0V when arc welding is On and intense…

It would be good to see your circuit and code.

Maybe try a 10K pullup resistor. In this case, the current will be within max spec of 0.1mA … it will be only 0.5mA if your supply is 5V. This might provide a better signal (well, anything is better than 0V).

Can you describe, or include a picture, of the shielding you currently have to protect the sensor and all the wiring from all the RFI the arc is producing.
I assume the arc is DC, tell us if it is not and what frequency is being used.

It may be better to monitor current, not the arc flash or smoke.

As MarkT touched on. Your environment is very electrically noisy. Can you take a photo or describe the physical implementation of your Arduino and sensor?

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