Sick 3D proximity laser scanner PLS 101-312 from 2000 teardown

[@SeanBZA]

Took apart a very old one, non laser, but used incandescent lamp as light source. 2 large area photodiodes. The round ring is used with the outer cover, the emitters are reflected through the plastic out, and then are giving a close area set of beams. Then any reflections are reflected back from the objects close by, and hit the photodiodes, so that it can detect if the sensor is dirty, and thus that the system cannot operate, so it will set an alarm, instead of carrying on running with the sensor being totally obscured with absorbent material. Detects if the surface is broken as well, causing a fail safe shut down as well.

[@1975RStefan]

Agree.

[@electronicbob6237]

It is not 3D...it is 2D Scanner

[@inse001]

It cannot do a raster scan, as there is only one axis of deflection. maybe something like a light curtain?

[@thatonedude8900]

i actually thought it was a coffeemaker when i saw the thumbnail and got incredibly confused.

[@TeardownOZ2CPU]

I am so sorry, did not mean to confuse

[@thatonedude8900]

@@TeardownOZ2CPU it was just a very funny moment cause it actually made me think sick had made one long ago for an april fools or something until the video started playing. xD

[@msylvain59]

Thanks, those things have been on my teardown wishlist for a long time, given how nice it is inside I will definiltely grab one if by any chance a deal pop up somewhere.

[@SeanBZA]

Ceramic hybrid looks like it is a flash ADC, with the covered box holding the multiple ultra fast comaprators and logic, and then the thin film resistors providing the reference voltages. 12 steps would likely be plenty enough, as this is not really needing much more, just really fast detection of the ramp, so 3.5 bits of ADC is plenty fast enough here.

[@zaprodk]

I would think the infrared sensors in the front are for the inset part of the black lens, so detect if something is obstructing the front of the lens. Doesn't it line up when the lens is mounted? Also the white disc on the back, could that be for calibration (a known target)?

[@sebidjdance]

It uses a high voltage infrared laser. The sensors and emitters around the viewport are for dirt dirt and water detection.

[@splitprissm9339]

MCS96 ... now that's some forgotten classic CPU!

[@1975RStefan]

23:24 That's the pulse laser diode, 24:30 that's the avalanche photo diode assembly. If clean up the dye cast housing, so don't affect the seat plane surfaces for the mirror rotor assembly an the other optical assemblies. Else it will result in minor misalignments affect the sensors accuracy.

[@electronicbob6237]

26:30 i think it is to measure the Pollution of the IR Window..

[@zaprodk]

19:28 Avalanche photodiode with high voltages?