Project 008 – Low-cost alternative

Color Meter for LED Modules

An LED lighting products manufacturer needed to color sort their white LEDs and LED fixtures in his production line. At the time, the white LEDs available to this manufacturer would not all have the exact same color and it was necessary to sort these fixtures to give each customers a batch of matched output color.

Because the production line was not yet automated, several color meters were needed to equip the different production stations. The client was worried about the high cost of a series of spectrometers. At that time, there were no off-the-shelf suitable cheaper alternatives for measuring the color output of white LEDs or LED fixtures. The client was looking for an affordable solution.

In this case, it was cost efficient to develop color meters based on simple RGB (red-green-blue) color sensors that would provide acceptable accuracy.

These USB color meters were built to easily and cost effectively sort the LED lighting products. By using a connected computer and a custom software application, the color meter itself could be kept very simple and low-cost. The software, written in Delphi Object Pascal, took care of the calibration and calculations and provided good visual feedback to the production line operators. The measurement data was stored for quality control purposes.

Diffusor disks and optical filters were used for best performance and to block the UV and IR light that would have affected the sensor readings.

For similar solutions, please see also Project 009 and Project 010.