Temperature Display Meter

[Bargeman]

Hello,

I am trying to identify a good value digital display meter that I can connect to a pipe thermostat to provide a display of temperature. The LCD digital thermometer modules available from Farnell (order nos 1186898 or 9933077) seem a bit pricey at ~ £60 each. Is anybody aware of a less costly alternative ?

regards

[djh]

A Maplin multimeter will likely display it but presumably you're looking for something labelled in degrees etc. Maplin do some temperature displays - maybe one of them is compatible with whatever the output of your thermostat is?

Cheers, Dave

[frotter]

I have a couple of these -

http://cgi.ebay.co.uk/Digital-2-LCD-Aquarium-Thermometer-Vivarium-Incuba-151_W0QQitemZ290197567332QQihZ019QQcategoryZ93679QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Not sure if its what you need but they are really cheap. Only read up to 70 degrees C though....

 

[Ivan]

Look up 'temperature module' in the maplin website.

I purchased several a few years ago. They are a bit smaller than the one that Mr. Frotter posted. They have an internal sensor, or you can purchase an optional externam sensor that needs to be soldered into place. I have about 6 or 7 of them showing things like woodstove flow and return temperature, ambient temperature etc etc. They run from a single 1.2v rechargeable (or a 1,5v non-rechargeable) - unlike some meters which don't like the lower voltage of rechargeables. They last for several months without needing a recharge, and they also have an over-temperature alarm or undertemperature alarm, which can be used to switch a transitor then relay if you want the thermometer to activate something - although I haven't used that. They cost me £2 on special offer. They go up to 70C.

Just had a quick look this is what I purchased (looks like I got a good price!):
http://www.maplin.co.uk/Module.aspx?ModuleNo=3261&criteria=digital%20temperature&doy=18m1

they also have this one:

http://www.maplin.co.uk/Module.aspx?ModuleNo=3258&criteria=temperature%20module&doy=18m1
only good for 50C and £9 including sensor

If you don't need a remote display, Navitron have a nice digital thermometer which works up to 150C for around £8+Vat. Or if you want to use it remotely, you could use a Navitron infra-red thermometer - these are around £38+vat



Ivan

[Antman]

How about stock code 85-2377  from http://www.rapidonline.com  ?

Up to 300C and 0.1 degree accuracy....

Ant

[The Crofter]

People often confuse resolution with accuracy.

Resolution can be either the smallest change detectable by the analogue to digital conversion circuit or the smallest change that is indicated by the display. In this instance it seems the display will only read to 0.1 degrees hence the quoted resolution. Assuming the onboard converter is an 8 bit device it can resolve the full 300 degree range to 1.17 degree steps (8 bit = 256 steps). If the range was 0-250 degrees then the resolution is 0.97 degrees.

The meter accuracy is quoted to be between 1 and 2 degrees. It would be better to obtain a meter that just covers the required range to get better resolution at this price point.

For £9 (ish) there is no way you can get a digital meter to give 0.1 degrees accuracy over the full temperature range, but I wish it were possible !

Cheers

[Ivan]

It looks very useful though - most digital temperature meters I've seen either go up to 50C or 70C. Whereas most applications I have (other than room temperature) require at least 100C, or sometimes over 200C.

[rob26440]

Bargeman,

Did you find a reasonable temp read out?  I recently bought a Digitron T600 on eBay.  It was £20.  Here is the spec: http://www.digitron-italia.com/en/termometri-laboratorio-t600.php

I don't know how much they are new.  It did not come with its probe or power supply, but the attraction for me is that it takes pt1000 sensors.  I have some pt1000 sensors in various locations that I want to take readings from.   I used a connector block and a 6 position rotary switch (from Maplin) and connected it to the probe input.  It was charged it up a couple of weeks ago using a std 12v phone type charger and it's not needed re-charging yet.  Good clear read out and appears to be accurate.  Saves me touring the house/loft to check on the temps.  Might be just the job if you can get hold of one.

Rob.

[Greenbeast]

how about:
http://www.reefdreams.co.uk/acatalog/PINPOINT-Wireless-Thermometer.html
comes with one wireless sensor, can take inputs from four

i'm currently looking to put together this as i didn't want to spend too much:
http://sci-toys.com/scitoys/scitoys/computers/thermometer/thermometer.html

[Antman]

People often confuse resolution with accuracy.

Resolution can be either the smallest change detectable by the analogue to digital conversion circuit or the smallest change that is indicated by the display. In this instance it seems the display will only read to 0.1 degrees hence the quoted resolution. Assuming the onboard converter is an 8 bit device it can resolve the full 300 degree range to 1.17 degree steps (8 bit = 256 steps). If the range was 0-250 degrees then the resolution is 0.97 degrees.

The meter accuracy is quoted to be between 1 and 2 degrees. It would be better to obtain a meter that just covers the required range to get better resolution at this price point.

For £9 (ish) there is no way you can get a digital meter to give 0.1 degrees accuracy over the full temperature range, but I wish it were possible !

Cheers

Maybe not - but I have compared it directly against the Resol sensors and it's within 0.1deg C from 18 thru 62 degC.
Therefore certainly at the lower end it would be fine for monitoring purposes.

Maybe I have a good one 

Antman

[The Slow Old Man]

Hi folks
I have to say that people get overly concerned with accuracy for these type of applications . Plus or minus one degree C is neither here nor there. It tends to be relative temperature change and linearity that tends to be more important IMHO.

Brian