GSM-thermometer of 2nd generation

There are a lot of different situations that associated with temperature critical processes. For instance conservatory, incubator, laboratory, etc. In such case it is often necessary to have a temperature monitoring system. Such a system allows owner to control necessary conditions 24 hours and get response in critical situations. With such idea behind the GSM-Thermometer can be used. It constantly checks the temperature of the environment and sends a text message to the owner’s smart phone in case of an incident.
To use the functionality of the GSM-Thermometer it takes the user two steps. The first step is to log in by sending a command to the module. The second step is to set the permissible temperature interval. While the Thermometer can establish a connection with one smartphone only, first user should log out to give ability for another user to log in.

Short overview of GSM-thermometer functions:

  • Logging into the GSM module
    User logs in before any action. To do so a SMS with the text “L” has to be send to the GSM module. The program saves the telephone number and answer “You are now a user of the GSM-thermometer. Your ID: $userPhoneNumber. Current temperature is $temperature. Default temperature interval is T=$tempLow ... $tempHigh.” From this moment user gets the current temperature interval.
  • Setting the temperature boundaries
    To change the temperature interval a user sends SMS with text “T Tmin Tmax” e.g. “T 20 30”. The correct form of this SMS is checked against a regular expression. Only if the form is valid the temperature interval is changed and the user gets informed about the changes via SMS.
  • Check the current state
    User can check the current temperature and the temperature interval by writing SMS with the text “C” and get an answer like “Current temperature is $T! Current set temperature interval is T = Tmin ... Tmax”.
  • Temperature monitoring
    In case the temperature gets out of the temperature interval user gets immediately informed: “Temperature too high(low)! Current temperature is $T”.
  • Logout of the GSM-module
    If the user has to be changed the current user logs out of the GSM module by sending a SMS with the text “LO”.