I am designing a circuit to measure the temperature via a thermistor via the ADC pin on a 328p and I am looking for some advice. As a failover I am also using an OP Amp as a comparator, to see whether the voltage exceeds a certain threshold. My question is the following. What can I do to protect the analog voltage line of the thermistor from interferences from the 328p? Can I connect the thermistor out directly to the 328p and to the MCU? My ideas are the following:
- Using an in-line diode before the 328P adc pin, so that it can measure voltage but not interfere with it.
- Using an OP Amp voltage follower to provide the voltage to the 328p pin
Is there a better way to do so? Are my possibilities feasible or are there any problems? What are the advantages and disadvantages of one or the other solution?
I am thankful for any help or advice.