High resolution stopwatch for cents

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Publication

Open-source software

Screenshot
WARNING: Download and run the software at your own risk. No responsibility for any loss, damage and/or adverse effect is granted.
No support is provided.
Visual C++ source code
Windows executable

Connecting the sensors to the microphone input

PhotoTransistor
PhotoTransistor
Ambient light phototransistors (TEPT4400) connected to the 3.5mm jack.
The microphone input of the sound card should be used. Heat shrink tubes are used to isolate the wires from directly touching them.
Farnell ordering pages: 3,5mm jack plug, TEPT4400, OFT-5301 (lowest cost infrared phototransistor)

Example experiment

PhotoTransistor
LED
The light source can be a flashlight, DC or mains lamp, no laser pointers are needed

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