Integrating Sphere for Luminance Calibration

One of our projects is to measure the luminance (brightness) of various sources of light pollution, using a digital camera. To do that, you need a calibrated source of luminance. It turns out that a low-cost purpose-made light integrating sphere can provide this. The linked paper describes the integrating sphere and provides some background information and theory.

Measurement tools are critical to this type of project. We used the DVM-101 digital multimeter to measure temperature and LED current; the CGR-201 oscilloscope to measure a light waveform and the ripple on a power supply voltage; the PSM-101 power supply to provide a regulated, adjustable DC source for the light emitting diodes.

As a teenager I worked on various science projects like this, but it was frustrating and difficult. Like all beginners, I was hampered by inexperience and lack of theoretical knowledge. My only measuring tool was an analog multimeter (built from a kit). Owning an oscilloscope was an impossible dream. So it is really a pleasure to be able to work with suitable tools.

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