London Banter - View Single Post

[email protected] · January 6th 05, 06:25 AM posted to uk.transport.london

wrote:

I have used a Fluke "Hydra" data logger in a lab situation. I was
capturing the data on a PC, but some models of the Hydra have
internal
memory. They can be operated from batteries. They can measure
voltage,
current, resistance, and temperature. I know it recorded the
relative
time (seconds since powerup) with each measurement, and I _think_ it
had
a time-of-day clock if you wanted absolute time. The models I'm
familiar
with don't have a housing that would stand up to being outside; if I
wanted to use one in your application I would put it in a big Pelican
case, maybe. The logger itself was about 3"x8"x8" (about 8x16x16 cm)
but the batteries and case would easily double or triple that volume.

I have never used one of these, but I know they exist:

http://www.onsetcomp.com/Products/Pr...al_logger.html
It has a thermocouple input, a clock, and a voltage input that might
be
able to record a dry contact closure to record the presence of
trains.
Getting the contact closure is left as an exercise for the reader.

All of this does assume that you have permission to hook things up on
the tracks. Otherwise the railroad will probably react badly to
unidentified boxes with wires hooked up to their track.

Matt Roberds

Thanks for your help Matt!

John