NTC thermistor timer setup arduino

by using Arduino mini pro 3.3v

I am planing to measure the temperature for the first five minutes, if the temp is over 40 degrees the device will send to Android app and flashy red led(sperated led).

if the device detects weight from pressure sensor to be more than 100 grams it will measure every 15 seconds for 5 mins. and then every 5 mins for the rest of 2 hours, the device will send data every 5 mins to app.

i am wondering what timer or isr will I be using in the programing side?

The thermistor is NTC RL0503-5820-97-MS nz.element14.com/.../2103813