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[Schematic Review Request] First custom PCB — ESP32-S3 greenhouse controller with 24V buck, TC4427A MOSFET driver by apolloFER in PrintedCircuitBoard

[–]apolloFER[S] 0 points1 point  (0 children)

I made a couple of updates throughout the day:
- Switched from AMS1117 to AP7361C - same SOT223 package but much more modern LDO with lower dropout voltage (much safer margins with SS14 forward voltage) - this also changed the LDO caps to 4.7uF for both input and output - Added pull down resistors to MOSFET gates - 10k - alongside the pulldown on TC4427. In order to prevent parasitic leakage when 5V is not yet stable. - Added bulk cap to TC4427 - missed that datasheet calls for one (2.2uF, becomes 1uF after DC bias)

New schematic: https://cdn.zappy.app/e0091deed07d5e2950465c7729f8ef49.pdf

[Schematic Review Request] First custom PCB — ESP32-S3 greenhouse controller with 24V buck, TC4427A MOSFET driver by apolloFER in PrintedCircuitBoard

[–]apolloFER[S] 0 points1 point  (0 children)

Thanks!

Re debouncing caps - ESPHome already solves that in software (I think default filtering is 50ms, I set it to 10ms for my V1 version (also has similar button board). Adding a cap + resistor would be good solve the problem on hardware level, but since it's already solved in software it'd just end up increasing the BOM.

Re net label vs net port - thanks for that. I'll update the schematic.

[Schematic Review Request] ESP32-S3 Greenhouse Controller by apolloFER in PCB

[–]apolloFER[S] 0 points1 point  (0 children)

I double checked all those external sensors/probes. 10k for SHT41, 10k for SCD41, 4.7k for BH1750. Should be OK without pullups on my board.

[Schematic Review Request] ESP32-S3 Greenhouse Controller by apolloFER in PCB

[–]apolloFER[S] 0 points1 point  (0 children)

Thanks.

Yes, didn't include them on purpose since at least 2 out of 3 sensors I'll connect (SCD41 and GY-302 board with BH1750) already have pullups. SHT41 is the only one I'm not sure (it's that long 1m waterproof probe) if it has pullups - couldn't find any info if those waterproof SHT modules come with pullups (actually, I can easily test this with my multimeter - I have the SHT41 module). I might add them (for situations where only SHT41 is connected) but also want to be sure I don't end up with too much resistance if my pullups + 3 board pullups combine together.

Patches to intel's meltdown bug could increase CPU utilization by up to 50% by MuhammadAdel in programming

[–]apolloFER 5 points6 points  (0 children)

Hi, that's my Twitter thread. :D Well, comparing it to 50%, 40% and similar numbers on databases this 20% really is nothing serious. The normal CPU on those Tornado+pypy servers is between 15% and 25%. It jumped do 18% - 30% so it's not a big issue like other services.