add comments files

Balu/Comments.txt

@@ -0,0 +1,26 @@
+Balu Mahesh
+1.	Design a system using a conductive water sensor (basically two metal probes that are very close together - when water is present between the probes it conducts) to detect when water level in a tank falls below 20% and when that happens, turn on a pump. The pump is a 3-phase 3-wire 1kW rated. This is for an industrial 	application where the water is being used for a chemical process. Design the system with some fail-safe such that the tank should never become empty.
+
+2.	Design summary is ok but could have been a little more detailed. Where is the fail-safe to prevent the tank from being completely empty?
+	How do you prevent overflow? How do you prevent the motor from running when input supply is not present? What about when the pump fails?
+	Basically there is no mention of the failsafe requirement.
+	What are the tadeoffs? How are you balancing cost, efficiency, and reliability? 
+	What is the meaning of "Zero PCB or card board"?
+
+3.	Block diagram: what is roof of the tank? The top of the tank? Or is the tank on the roof of a building?
+	The block diagram is confusing: what is the meaning of "exception?" Which of thse lines are signal and which are power??
+	
+4.	Power supply design is totally absent.
+
+5.	Industrial Design:
+	Your text is directly lifted from https://sg.rs-online.com/web/c/enclosures-server-racks/enclosures/pcb-mounting-enclosures/
+
+6.	KICAD Design
+	Schematic:
+	Did you use this circuit? even the values are identical: https://easyelectronicsproject.com/wp-content/uploads/2020/10/Water-Pump-Auto-Switch-Pic-12.jpg?x56667
+	
+	PCB:
+	Layout seems ok
+	DRC is not passing because there is no outline.
+	
+7. Pricing / Assembly: Items costs are ok although grossly underestimated. No mention of materials for the actual probes, wiring, etc ???

Lokesh/Comments.txt

@@ -0,0 +1,41 @@
+Name: Lokesh
+
+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:
+	Your design is well thought out. Using the cascaded power supply for local boards and wireless link to control room is also a good point.
+	In reality you will have to check if the industry allows wireless, which bands, or whether they want some MODbus type system.
+	One major issue in your design is that you are using a FET as the frontend - how will you account for variations in the FET gm? Each board
+	will have a different gain which you need to calibrate. Similarly each sensor has a different gain and sensitivity which you need to calibrate,
+	you should have mentioned that.
+	
+
+3.	Block diagram
+	Block diagram is fine.
+	Some details are missing - for example what are the protocols / signal levels between the boards?
+	What happens when multiple sensors go off - are there some ways to tell the control room wchich sensors have gone off?
+	Or how many?
+
+	
+4.	Power supply design
+	Why have you chosen a rectifier supply? Can you not choose an off the shelf switching sypply?
+	Are you gonig to supply different PSU for every different voltage level in industry?
+	
+5.	Industrial Design:
+	Mostly ok - dimensioning could be better. Also, are there wires coming out of the box?
+	Or are there connectors on the edge? or are there some cable glands?
+
+6.	KICAD Design
+	Schematic:
+	Major flaw in circuit design - your 5V regulated is not ground referenced. So any noise / disturbance in the power line will make it into the output.
+	
+	PCB:
+	Board outline is missing and DRC fails
+	Why mix SMT and THT components? Also interesting that your THT components are on the back. Why?
+	Some unconnected stubs on your board - e.g. 
+	
+7.	Pricing / Assembly