[bodiby] was first to send in this New Scientist article about converting a DVD drive into a lab scanner. I did some digging and came up with the details. Here’s the paper describing the process and results. Here’s a basic schematic and description of the mod. A set of samples is placed onto a CDR. A photo sensor is used to locate the samples on the CD, while the laser is fired through each sample. A planar photodiode is used to measure the attenuation of the laser as it’s transmitted through each sample. Sadly, I couldn’t find any details on the custom control electronics.