On Mon, 28 Apr 2003, John Rodgers wrote:

> However, I have been investigating a do-it-yourself scheme whereby an
> indicator could be built from off the shelf electronics parts from your
> local FLES (Friendly local electronics store ...yeah, yeah, yeah!) I'm
> not an electronics whiz but it seems a reasonable approach. I have found
> stuff on the net whereby such things are done, and LED's are used to
> provide digital readouts. I think it would be cool to get a fairly
> accurate and rapid readout on temperature to compare to the official
> temperature guage.

On my '75, I had a home-made digital temp gauge.  I used an LM34
"Precision Fahrenheit Temperature Sender", which costs a few bucks.  The
great thing about this sender is that its output voltage is simply the
temperature in degrees F times 0.01V.  It's accurate to +/- 0.5 degree.
 For a readout I used a digital LCD panel voltmeter, with the decimal
point wired to be two places to the right of where it normally would be --
this gave a direct readout in degrees F.  The sender comes in several
formats; I used the version that's in a TO-92 transistor case.  This was
an aircooled engine, so I glued the sender between the fins at the bottom
of the oil sump.  It worked pretty well.

I'm not sure how you'd adapt this kind of thing to a watercooled engine,
but it gives you an idea of what's out there.

For quick spot checks, an infrared temperature "gun" is a good option.
You can get them for around $60.  Hard to use while driving, though. ;)

David Brodbeck, N8SRE
'82 Diesel Westfalia
'94 Honda Civic Si