Hey,
I am currently designing a custom board for a music festival led project (around 36 diffusors of 2,5m ws2815).
Would be glad to get some feedback on the schematic and pcb! Best regards
3 things that strike at a quick glance:
- You don’t want the thin connections between ground pads and ground plane, makes no sense when the + supply is “full contact”.
- Don’t connect the voltage supply directly to USB VBUS, at least add a diode so if the supply is connected it can’t backfeed into the PC and fry the USB port.
- Use the “good” level shifter if you’re gonna put the effort of making a custom board.
if you only need 2 Channesl so why not stayioing with a D1 wemos at 5USD no shifter needed as of ESP8266 this can easy handle the needs
It is not a good idea to skip the shifter if taking the time to design a pcb. There is no guarantee the LEDs will work correctly as you are still hoping to run them off a data voltage they were not spec’ed for. Also no level shifter means you will need to keep the first LED close to the controller. The benefits of having a shifter far out weigh saving a $1.
As stated by JINX. Also, bcs. we will do a large festival floor installation and need 15+ boards, with level shifters and resistances for reliability, fuses (4A+ current per stripe), voltage regulator (ws2815 use 12V), etc… Manually soldering dev-boards and further party would consume a lot of time and space.
From my experience, ESP32 is way more reliable than ESP8266 for outdoor usage.
I find the 32’s to have better wifi coverage too. But I could be crazy 
Thanks for the feedback! I already wondered about the cross-shaped pad connections on my last project. Now I learned something about thermal spokes vs direct connection.
→
- Changed GND copper fill to direct connection
- Replaced the level shifter with faster SN74LVC2T45DCUR
I won’t add a diode, since the controllers will never be connected to computer and led at the same time. The 5V USB port ist for convenience, aka powering short strips over mobile phone chargers.
Did some clean up and restructuring, to make it more compact and symmetric, and reduce crossovers. Final Design:
Stupid question (bcs I am a noob): You refer to a Schottky Barrier Diode to protect the USB port from backfeeding, right? Would 3A (or say 5A) be adequate, since the usb port ist 3A max?
Yeah that’d be fine.
Better safe than sorry the day you or someone else needs to reflash from USB and forgot/doesn’t know.