For me, it helped me to look at open source hardware like adafruit's. The Mini Sparkle is a 4 layer and available on their github https://github.com/adafruit/A

For me, it helped me to look at open source hardware like adafruit's. The Mini Sparkle is a 4 layer and available on their github https://github.com/adafruit/Adafruit-Mini-Sparkle-Motion-PCB https://github.com/adafruit/Adafruit-Mini-Sparkle-Motion-PCB There are many more available at OSHWA : https://certification.oshwa.org/list.html https://certification.oshwa.org/list.html