RGB Sensor Becomes a Low-Resolution Scanner

Scanners, in our modern world, aren’t things we normally think about. Perhaps you have one that was a nice added feature on a printer, but a smartphone can usually work in a pinch. On the other hand, the technology that goes into them is a rather interesting assortment of devices, using a specialized linear CCD pass over the document and capture the resulting RGB values.

It would then be possible to make a scanner with a gantry setup and an RGB sensor. Demonstrating this concept, Kerry D. Wong constructed his own by mounting a TCS34725 sensor on an HP 7044A plotter, using an Arduino Due to control its movements and record the resulting values. From here, these RGB values are passed along serially to a computer that records them in a text file, which finally reconstructs them into an image using MATLAB.

The big drawback to this method is that scanning is quite slow, due to the sensor’s roughly 150ms pixel acquisition time. Though the results look quite accurate, his process takes around 50 minutes for a 128 x 128 pixel scan. So it’s an interesting technology demonstrator, but not something that you’d want to use to preserve family memories. Still though, this concept could be used with any machine that has an X/Y gantry, such as a CNC router or 3D printer. A robot arm could be outfitted in such a way. Hopefully this will inspire other interesting experiments in the future!