DigitalNigel

I picked up a used Emerson Liebert Vertiv GXT4 Double-Conversion UPS a little while back to better handle the dirty power coming from my portable generator, while feeding my server cabinet at the house. The internal batteries work fine, but I wanted to wire in some additional batteries for extra runtime before the generator would actually be needed. Unfortunately, it seems the external battery pack cable is exceedingly hard to find.

As my UPS is a 48V battery pack model, I believe the right cable for mine would be model number GXT3CABLE48V1, unfortunately, that proved to be effectively impossible to reasonably source. I did find some GXT3CABLE144V1 model cables that in the pictures looked essentially identical, so I took a gamble and ordered one.

I’ve found that the cables are effectively the same, but the plugs are keyed differently. So, all I needed to do was shave off the keying on the cable, and it worked fine in my UPS. Below is a photo of the shaved version above, and the stock version below. Hopefully someone else finds that helpful as well.

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.