Maddy from Little Bird Electronics suggested I go direct to the experts so here goes..
My requirement is:- 20 Rooms temperature to monitor
In Place:- We currently monitor these rooms back to a patch panel that displays this info. Using TP2000 Probes. These use resistance which from the output of the dislpays creates a output voltage which I wish to use as input.
New Requirement:- If the Temp gets above or below n degrees C a SMS alert is sent to a tech. Data to be logged on a pc. I can code any program for the data logging / sending alerts etc but electronics is not my strong point. Intermediate understanding though. (Plus google).
It has been suggested to use the Arduino Mega 2560 along with a ArduinoGSM Shield (for connectivity / sms).
Issue.. As this Arduino board only accepts max 5v as input (able to have 50 inputs) how can I step the voltage down. Ie. If the shed is 30 degrees c then the input will be 5v If the shed is 15 degrees c then the input will be 2.5 etc etc..
Is the Arduino the answer to use along with sonething to step the voltage down for input.. or is there something better that may meet my needs.