EEVblog Electronics Community Forum

Electronics => Projects, Designs, and Technical Stuff => Topic started by: jones12 on April 26, 2018, 07:53:15 am

Title: First Schematic
Post by: jones12 on April 26, 2018, 07:53:15 am

Hey guys,

I'm in the process of designing aa arduino controlled fan system that works off temperature (DHT11)
I've got the code and prototype working so the next stage is the schematic.
My first schematic was a write off, but I've read up on what I needed to fix and revised it. Hoping I've got it right this time!

Im a third year electrical engineering student and believe it or not they teach us very little CAD in the course....

Is this the right place to post it and ask for people to have a look at and offer their opinions?

Its attached as a PDF but i'll include an image link below as well:
https://imgur.com/CaNGcaX (https://imgur.com/CaNGcaX)



Cheers all!
Caleb.

Title: Re: First Schematic
Post by: hamster_nz on April 26, 2018, 08:48:21 am

Is there question in there?

On thing I am not so sure on is that it is hard to see that the PWM signal is connected to the gates on the MOSFETs.

Ditto for the TEMP signal being connected to the DHT11.

Title: Re: First Schematic
Post by: Theobald on April 26, 2018, 08:52:16 am

Hi Jones12,

1) AVCC is not powered. Check user manual.
2) Add a capacitor on the RESET pin, --> check the user manual for power on reset and it helps for EMC immunity.
3) Just in case, add diode in the power supply plug. If the current is to high, place the diode in parallel and add a fuse.
4) C4/C5 should have the same value. If X1's CL=12.5pF, keep 22p for both.

Theo