SparkFun Forums

[barger]

I am new to this site so I hope I am in the correct location to ask this question.
I know very little about electronics, so please allow for this fact.
I would like to build a device that will monitor temperature in 4 different locations using 10K thermisters.
I would like to be able to turn the monitor on and off (switch), and be able to scroll through 4 different locations using a push button (momentary push switch)
I would like to display digitally each location, and its temperature in F degrees.
The temperatures being measured will be -20 degrees F to 200 degrees F
I have searched the internet for such a device, but all similar devices are programmable temp controls, and or alarms.
I simply need just to monitor the temperature only.
If someone could help me with what I will need to buy, and how to proceed I would be grateful.
I will need to put components in an enclosure that can be mounted on the wall.
Thanks

[Mee_n_Mac]

Sounds easy enough but may I ask why a thermistor ? You'll need to calibrate them to get acceptable accuracy. And I assume they'll be hardwired to the enclosure, how long would these wires be ? Basically any microcontroller could do the measuring and control the display. And I'd recommend you start there, look over some displays and see what you like. You might find one to display all 4 temps.

[barger]

All four 10K thermistors are already in place, one of which would be very hard to replace. The thermistors are hard wired with thermostat wire, with the longest run being about 60 - 70 feet long.
I could use some guidance as to which microcontroller to look at, as I really not familiar with what will work.
Thanks for your input.

[Mee_n_Mac]

I could use some guidance as to which microcontroller to look at, as I really not familiar with what will work. Thanks for your input.

An Arduino Uno or one of it's ilk might be a good choice as you're likely to find a plugin 'shield' display to your liking.

For example ...
https://www.sparkfun.com/products/11851

UNO and ilk ...
https://www.sparkfun.com/products/11021
https://www.sparkfun.com/products/11224
https://www.sparkfun.com/products/11575

[lyndon]

Do you have the specifications for the thermistors? If you are going to build a readout you will either need that or you'll have to do calibrations at multiple temperature points.

[barger]

All I know is that they are 10k thermistors
I am replacing an old monitor that no longer is avaliable.

[lyndon]

Then you will probably be better off replacing the entire system. Saying "10k" thermistor is meaningless unless you know the manufacturer part number. Many thermistors are specified as 10kohms at 25C. The problem is that they are nonlinear and their curves aren't all the same, so they won't measure the same at different temps.

All I know is that they are 10k thermistors
I am replacing an old monitor that no longer is avaliable.

[barger]

OK so if i go with new temp sensors what do you recommend i use?
Also, I would like some sort of enclosure that can be mounted on a wall.
Thanks for the help

[lyndon]

Here's a DIY version http://dangerousprototypes.com/2012/05/ ... e-monitor/