Parts and how to make a digital thermometer for out in the workshop

[apples]

I want to look into making a digital thermometer that read out on a red led 7 segment display.

I did search the forums and found a plan to follow, but the IC's CA3162 and CA3161 seem to be old parts and they are quite expensive.

Surely there must be a newer and cheaper IC that do the same job? How do I go about finding these newer parts?

 

[GreenGiant]

How much is "quite expensive"?

There are tons of ways that you can do this, did you have any particular type of temperature measurement device in mind? (thermocouple, thermal resistor, thermal transistor, etc)

from the parts listed you will need something with a linear slope with temperature change. My opinion would be a thermocouple, yes you will need additional circuitry to amplify the signal but they are much more accurate and generally have a more dramatic change with temperature so it will be easier to read a change.

 

[apples]

Hi, I looked on ebay and can get those two ic's for 12.75 and 9.23 = 21.98 total. From China about 20 days delivery from China though. So it seems hard to find them and while 22 dollars is not that much, it is still 22 dollars, when you have no spare money to spend on these projects anyway every cent saved helps.

The plans for the build I found use the LM35 temp sensor, I think I have a dallas ds18B20 one wire temp sensor. I think both these are good for 0.5 deg accuracy, maybe a little more accuracy would be okay,but then again it is only for my personal comfort to know what the temperature it is. That temp sensor I got for my arduino and lcd screen, butdo not want to use that for a workshop temp gauge (cost wise).

So that is where I am at.