GUVA S12SD Calibration

General project help for Adafruit customers

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
User avatar
nathalie_
 
Posts: 3
Joined: Tue Apr 24, 2018 9:25 am

GUVA S12SD Calibration

Post by nathalie_ »

Hi all!

My GUVA-S12SD UV light breakout sensors (Link to product: https://www.adafruit.com/product/1918) seem to respond to stimuli quite OK. However, in some instances, it seems that when there is no input some of them will still show relatively high values (e.g. most show 0 and some show values >20). Is there a way to calibrate them to some sort of baseline?

All help will be very much appreciated!
Many thanks, Nathalie

User avatar
adafruit_support_bill
 
Posts: 88093
Joined: Sat Feb 07, 2009 10:11 am

Re: GUVA S12SD Calibration

Post by adafruit_support_bill »

it seems that when there is no input some of them will still show relatively high values (e.g. most show 0 and some show values >20).
So some of the sensors show high output values even if you cover the sensor? Please post a photo showing your soldering and connections to the problem sensor(s).

How many sensors total do you have? Do most of them show reasonably consistent values?

User avatar
nathalie_
 
Posts: 3
Joined: Tue Apr 24, 2018 9:25 am

Re: GUVA S12SD Calibration

Post by nathalie_ »

Dear Bill, thank you for getting back to me so quickly!

I have attached a picture of the sensor in this example. The soldering doesn't look too bad. There are eight sensors at the moment, and they usually show 0 (just like in the picture) however on different moments, I might have an aberrant one (in this case the second from the left). Today it was two instead of 0, but sometimes the value can go up to 100 as you can see in one of the screenshots (while the rest show 0).

After taking those pictures, I switched the sensor positions to see what happens and they all went down to 0, but in the future, when the circuit is soldered on a PCB I won't be able to do that. Do you have any recommendations for getting them all to baseline? Or, do you think I might be dealing with a hardware/circuit issue?

Once again, thank you very much for your help,
All the Best,
Nathalie
Attachments
Exposed to Light
Exposed to Light
sun exposure.PNG (14.53 KiB) Viewed 241 times
Sensor Close-up
Sensor Close-up
soldering.PNG (52.93 KiB) Viewed 241 times
Before exposure
Before exposure
no exposure.PNG (13.89 KiB) Viewed 241 times

User avatar
adafruit_support_bill
 
Posts: 88093
Joined: Sat Feb 07, 2009 10:11 am

Re: GUVA S12SD Calibration

Post by adafruit_support_bill »

There are eight sensors at the moment, and they usually show 0 (just like in the picture) however on different moments, I might have an aberrant one (in this case the second from the left).
We did have a batch of mismarked parts a while ago. But the symptom there was high readings all of the time.
After taking those pictures, I switched the sensor positions to see what happens and they all went down to 0, but in the future, when the circuit is soldered on a PCB I won't be able to do that.
So you currently are using these on a breadboard? Based on the intermittent nature of the problem, I would suspect that you have a marginal connection somewhere. From what I can see in the photo, the soldering looks OK. But jumper wires and breadboard connections can be unreliable.

The next time you see abnormal readings, try re-wiring just the offending sensor with a different set of jumper wires. Make sure that they are all firmly gripped by the contacts in the breadboard. If that does not fix the problem, let us know and we can investigate further.

User avatar
nathalie_
 
Posts: 3
Joined: Tue Apr 24, 2018 9:25 am

Re: GUVA S12SD Calibration

Post by nathalie_ »

Sounds like a plan!

Thank you once again for your help!
Nathalie

Locked
Please be positive and constructive with your questions and comments.

Return to “General Project help”