From: Gary Tait
Subject: Re: thermometer
X-Newsreader: Forte Free Agent 1.92/32.572
Date: Fri, 13 Dec 2002 10:44:23 -0500
NNTP-Posting-Date: Fri, 13 Dec 2002 10:45:27 EST
Organization: WorldCom Canada Ltd. News Reader Service
On Fri, 13 Dec 2002 08:41:45 +0200, "Niclas Forsen"
>I'm a real newbie when it comes to electronics, but I have a project idea
>that I would need som help with. My idea is to make a indoors thermometer
>that would be the same shape as a big mercury thermometer, but lit by leds.
>What I would need help with is, well, everything, hehe. I know there are
>different temperature sensors, but how do I get the output from a sensor
>interpreted to what leds to light up? The scale on the thermometer would be
>something from +18 to +26 degrees centigrade and maybe 4-6 leds/degree would
>light up, for instance 18 degrees only first led on, 19 degrees 5 leds, 20
>degrees 9 leds and so on. Any help would be very good, even if it's just a
>book title for an electonics book for newbies. Of course, some real circuit
>designs would be even better! :)
The easy thing to do would be to use an analog temperature sensor (I
am not sure of the part number, but it is a National part, and
proportionally puts out voltage to the temperature), and a few
LM3914 bar meters. Another solution would be to use a micro to
read form a 2 wire temperature sensor, and directly display that to a
multiplexed LED array.