Vintage military temp guage

[idk110]

I was thinking about purchasing an old military temp gauge (from a jeep i think) to go with my pc build. It says 24v. Would i be able to hook it up to my psu? I'm aware that its difficult to convert 24 to 12v, but does this gauge really require that much power?

 

[idk110]

I might be wiring a cell phone up to use as a temp monitor instead(for a sweet touchscreen display/android on the front of my case)
........using
http://www.ebay.com/itm/DC-DC-Step-Down-Power-Module-4V-38V-to-1-25V-36V-LED-Voltmeter-Adjustable-5A-new-/331471874924?hash=item4d2d436b6c
and
http://thermodo.com/
for the temp monitor.
I'm planning to use an HTC desire c