take measurements

to get max_heating_rate:
- plug in thermocouple
- set PWM to 100%
- record temp / time
- consider thermal intertia. the earlier measurements might not be representative

to get cooling_coefficient:
- Heat to some temp (i.e. 1000C)
- stabilize the temperature
- record ambient temperature
- set PWM to 0%
- record temp / time
- $T(t)=T_{\text{ambient}}​ + (T(0)−T_{\text{ambient}}​) \cdot e^{−kt}$
- where $T(0)$ is the target temp (i.e. 1000C)
- Also need to convert sim.py to use exponential model