Trouble getting the PT to pick up the lighting up LED on screen

[cbachhuber]

@wpeirkcfj wrote

I am very interested in your Glass to Glass Delay Measurement System project and bought my own equipment to try to reproduce it. But after setting up this project, I found that during the test delay process, if the system works normally when the LED is placed directly on the PT, it is normal to shoot the LED through the mobile phone screen and then use the PT to receive it, but when the LED is placed The system does not work properly when on the computer screen. PT cannot receive the light displayed by the LED through the computer screen. I was wondering if you could help me with this.
I sincerely appreciate your help and guidance.

Let's discuss his request in this issue.

[cbachhuber]

To me, this sounds like the threshold might be too high. Can you try the following things to troubleshoot?

• What's listed here
• Ensure that the correct side of the PT is facing the screen
• Try lowering these thresholds and see if the system picks up the delay. Careful: too low values may make the system reactto noise.
• If nothing above works, you can debug yourself: you can print the brightness values that the PT sees over time by printing these values. Consider printing them to a terminal and plotting them. This curve should be mostly constant, with a jump in value when the LED is turning on from the PT's perspective.