Q$1)(20$ marks$)$

You have been tasked with designing a microcontroller$-$based temperature control mechanism using a radiator and an air conditioner. The temperature is sensed at intervals of $10$ s $.$ If the temperature is above $T_{t{h}_h\text{i}\text{g}\text{h}\text{,}}$ then the air conditioner is turned on until the next measurement cycle starts. If the temperature is below $T_{t{h}_{l}ow,}$ the radiator is turned on$,$ again until the ney measurement cycle. If the temperature falls between $T_{t{h}_{l}ow}$ and $T_{t{h}_h\text{i}\text{g}\text{h}\text{,}}$ th system idles.

a$)$ What sensing mechanism will you use for the above system, if used for i$)$ and industrial application with temperature values above $500$degC and

ii$)$ A home automation application with temperatures between $-20$degC and $40$ degC. What is the sensing principle for each sensor$?(4$ marks$)$

b$)$ Elaborate on the desired characteristics for the sensors$.(4$ marks$)$

c$)$ How will you interface the $2$ different sensors to a microcontroller? $(4$ marks$)$

d$)$ What can be the sources of error in the sensing mechanism? $(4$ marks$)$

e$)$ If the tolerable quantization noise is $100V,$ determine an appropriate $V_{\text{R}\text{E}\text{F}}$ and resolution for the ADC. $(4$ marks$)$