SMD ESP8266 relay board check to see if ready for pcb+assembly - Page 1
Forum section: electronics / projects

author: Stealthrt
author_rank: Regular Contributor
timestamp: October 13, 2023, 04:45:52 pm
content: Hey all I have finished my design of my 2-relay board that I will be using in my car to turn on monitors.I've been all around this design making sure everything is connected but I would like to have others who are more knowable on these things to lend a hand and let me know if the design is good or something needs to be changed/corrected/orientation.I will be ordering the PCB + assembly service from JLCPCB and its around $60 for 2 of them so I want to make sure my design will work as I do not have any parts to build a prototype. I have all the correct JLC parts listed for each of the components and all that looks good when using the BOM and P&P files on the JLCPCB site - all in stock.I have attached my Kicad schematic and board layout for easier viewing but also have attached images of the schematic and board.Please look it over and let me know if something needs to be changed or anything really! A little nervous about not being correct!

author: Benta
author_rank: Super Contributor
timestamp: October 13, 2023, 08:43:57 pm
content: Dunno what you want us to say.Schematic looks OK, no idea about functionality except for a couple of relays with BJT drivers.PCB: track widths look OK but hard to say. A PCB layout screentshot would be better.The 3D stuff is for your own satisfaction, unnecessary for production.That's it.

author: Stealthrt
author_rank: Regular Contributor
timestamp: October 14, 2023, 03:38:32 am
content: Thanks for your reply and input @Benta

author: Shonky
author_rank: Frequent Contributor
timestamp: October 14, 2023, 09:46:36 am
content: Ground supply to the micro board takes a rather long route via J2 and J3 around the board when it's right there straight off the regulator. So higher external device current draws could cause issues withWhere does the always on +12v output connect on the schematic?Not a huge fan of the schematic layout. I try where possible to go left to right. Not always possible but when you start putting capacitors on upside down, going around in circles etc can lead to mistakes. This is simple enough it's not really an issue but keep in mindDoes it pass a DRC?

author: tooki
author_rank: Super Contributor
timestamp: October 14, 2023, 12:21:31 pm
content: Eh, I mean, it'll work... but it ain't pretty. A lot of unnecessarily circuitous routing.Given that you're using an ESP, I assume this will use Wi-Fi. That needs pulses of significant power, so right now, the dinky thin ground going to it (via an unnecessarily complex path) could produce more EMI than a more direct path. Is there any reason not to use a ground pour (with a cutout under the upper part of the ESP so it doesn't shield the Wi-Fi) to give yourself a nice solid ground reference?I've attached an example (the two transistors) of unnecessarily complex routing, with traces going underneath when not necessary. This makes it harder to follow a circuit, and much harder to modify it after the fact, should a bodge ever be needed. The attachment shows how the parts could be laid out in a much cleaner fashion. (Both transistors shown, two variants shown for Q1. The blue traces are the original, the green traces the suggestions. Dotted lines show alternate via positioning to avoid going underneath any other parts.)

author: floobydust
author_rank: Super Contributor
timestamp: October 15, 2023, 01:15:58 am
content: How many amps is the load? What's the fuse rating?Some things I see:I don't like the via's small annular rings or the skinny traces. Mornsun pin 4 GND needs more than a single via. So do the terminal blocks for the output(-), run another fat trace.The MornsunK7805JT-500R3buck-converter is not protected against -ve transients, I would include a series diode and maybe a small fuse for it - if the main fuse is huge it will not prevent bad things if the Mornsun fails.You can instead use relays with a 12V coil to lighten the load on the 5V rail. But during cranking they might cut out.