From 8d157d2d78d99697776ff0438f669ed41e6b321b Mon Sep 17 00:00:00 2001 From: Abhijit Kshirsagar Date: Thu, 28 Apr 2022 11:05:39 +0530 Subject: [PATCH] Phanindra --- Phanindra/Comments.txt | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 Phanindra/Comments.txt diff --git a/Phanindra/Comments.txt b/Phanindra/Comments.txt new file mode 100644 index 0000000..05a9cc3 --- /dev/null +++ b/Phanindra/Comments.txt @@ -0,0 +1,38 @@ +Name + +1. Question text: + CO sensor + + +2. Design summary: + Very well written. Low Battery detection / alert is especially well done + +3. Block diagram + Where is the block diagram? + you have given the entire electrical circuit diagram here. + Only some logical / hierarchical block diagram was needed here. + +4. Power supply design + There are two major probems with your design. + a. The 9V battery you have chosen is not exactly good for long life. Look at other products that need long life batteries - + all use some kind of non-rechargeable lithium cells. + b. You are using a linear regulator which has expremely poor efficiency - you're going from 9V to 5V! + Should have used a 6V battery and LDO. + Microcontroller - pick one with low power consumption and/or sleep modes like the MSP430 or AtTiny. + +5. Industrial Design: + Summary is fine - should have included sketches of the final unit. Where should the LED be? Where are the mountings for + buzzer / speaker? + +6. KICAD Design + Schematic: + No major issues seen + + PCB: + Layout could be a little better - you have many traces intersecting / overlapping. + Especially look at the sensor heater supply - those traces could be thicker. + What is the current needed there? + +7. Pricing / BOM / Assembly + Some BOM optimisation could have been done - mostly all ok + Price for 2 prototypes not mentiones?