Modify a kinect – Reconnect the two cards

I see a fundamental units problem in your math. You are using the symbol m which stands for milli (10^-3). The actual energies are µ (10^-6). You are off by a factor of 10^-3. Since most keyboards do not have a symbol for µ (micro), people often revert to an m (milli), and end up confusing the units. Hey, they both start with the same letter, right? :)

Additionally, there is the question of "wall plug efficiency". While a diode may 60mW, even military grade lasers only have a 10-15% wall plug efficiency. Thus that means an output of around 6mW. Then any optical element will reduce power by around 50% for each element. Assuming at most 2 optical elements (nu-naturally low number), that means the output can at max be 1.5mW.

In the answer you quoted, use this paragraph as a point of comparison:

For the sake of comparison, sunlight is one kilowatt per square meter and perhaps 5% of that is near infrared i.e. 700 to 1000 nanometers. Just going outside will expose you to much greater power densities of SWIR than the Kinect.

Also, remember that even though the generator is 60 mW (yes, I used the correct units), there is a series of diffusers, optics, and such so that at the very extreme of the exit aperture, the power density is <25 μW (again, note the symbol). The series of steps required to get at the 60 mW generator would indicate a willful intent to cause self harm, and be beyond simple mechanical failure.

Your initial assumption is incorrect.

My approach is as follows: - Assume 60mW output power is correct - Diffuser efficiency is 50% and therefore 50% of the energy is lost

The diffusers and optics reduce the power to <25 μW at the aperture. Run your math with that figure and you'll have an accurate representation.

Even if you could get the data into an 8-bit microcontroller like an Arduino, it would be completely inadequate to process it. According to Wikipedia, the depth information streaming out of the Kinect is 640x480, 11-bits of resolution. That's about 600 kB of raw data for each frame, and the frame rate is 30 Hz. So, we need to crank through about 18 MB of data each second. This isn't too big of a challenge for a PC, but it's of the league of something like an Arduino.

Instead, you may have better luck using something like a Raspberry Pi. It has a 32-bit ARM microprocessor running at 700 MHz, 256 MB of RAM, and a GPU. It's basically a PC from 8 years ago on a single board.