I got one of the little Bosch laser tape measure devices as a gift for the holidays. It’s an impressive little device, and is remarkably accurate. I’m curious how it makes the measurement, because the timing requirements to directly measure time of flight for a laser beam over the course of a couple feet are quite tight.
I used the same photodiode setup I put together for measuring the accuracy of a mechanical clock, and took a look at the signals.
It does seem like they’re doing some modulation on the laser beam, but I haven’t dug further to come to any conclusions yet on how they’re actually deriving a distance. Pretty neat tool though.