Screen Trigger Device specifications

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Description

The screen trigger device is a small optical sensor that can be mounted in the corner of a screen. It contains a photo diode with build in amplifier that senses the intensity of the screen locally. It has a BNC output that gives 0 Volt output when the screen is locally black and 5 V output when the screen is locally white. This can be used to create a digital timing signal for changes on the screen.

Design

The screen trigger devices has a TSL25xR photo sensor with build-in amplifier.

Screen Trigger Schematics

Components

  • Box: Hammond 1551 Series Black ABS Enclosure, IP54, Flanged, 50 x 35 x 20mm
  • Power supply: 5V, 2.5A, 2-Pin Type C - EuroPlug with 2.1mm DC connector
  • Socket: Cliff Electronic Components DC10A SOCKET, PCB, DC POWER, 2.1MM, PK10
  • Photo Diode: Taos TSL25xR
  • Resistor: 10 kOhm

Specsheet photo diode

TSL25xR specs

Speed test Screen Trigger Device

A led was connected to the output of the function generator. The led was used to illuminate the photodiode.

The function generator signal is shown in yellow.

The output of the screen trigger detector is shown in red.

Risetime and falltime of the screen trigger detector is about 0.2 mSec TSL25xR specs