Name: Swakath

1.	Question text:
Design a system using this Honeywell ammonia sensor (https://drive.google.com/file/d/164WvPD7GauvseOfH-K3v8iZ4YYmQFkq-/view?usp=sharing ) to detect when ammonia concentration in ambient atmosphere exceeds 100 ppm an alert an operator in a control room about 100m away. This device will be mounted in various sections of an industrial processing plant. The complete plant will need a fairly large number (~20) of sensors so unit costs needs to be kept under control. Also, once mounted it will be very difficult to remove/service/repair the sensing devices.


2.	Design summary:
	Overall approach is fine.
	Good work finding th module that has a 4-20mA output directly


3.	Block diagram
	Why is there a common supply for both the sensor module and the receiver module?
	They might be physically very far apart!
	
4.	Power supply design
	The brick module may end up being underpowered for what you need.
	Also, why design a rectifier filter and then use the module?
	Power in a current-driven system is indeed tricky - you need to factor in the worst case 
	voltage drop and times the current is power. 

5.	Industrial Design:


6.	KICAD Design
	Schematic:
	All good - good use of decoupling caps.
	No Power on LED?
	How exactly is the fault opamp working?
	Also the OpAmp outputs are +/-12V. If you're connecting this to the uC you need to scale down to 5V or 3v3.

	
	PCB:
	No Mounting holes?
	Good use of pours
	
7.	Pricing / BOM / Assembly
	The question asked for 2 prototypes - meaning two systems with about 20 sensor modules each.
	But I guess this interpretation is fine too.