Kids OK, with an adult
DIY project. Children must build this only with an adult (16+ years) beside them at all times. Not suitable for children under 8 years.
Avoid GPIO 35–37 (used by the PSRAM), 0, 45, 46 (boot pins) and 19/20 (USB). An adult must handle and charge the 18650 cell.
Strictly follow the description given with this video.