Compact USB-powered desktop CO₂ air quality monitor using an NDIR CO₂ sensor, microcontroller, OLED display, and visual good/m... show moreCompact USB-powered desktop CO₂ air quality monitor using an NDIR CO₂ sensor, microcontroller, OLED display, and visual...
Hand-solderable 9V battery-powered red LED blinker using a 555 timer, on/off switch, through-hole passives, and a PP3 battery holder.Hand-solderable 9V battery-powered red LED blinker using a 555 timer, on/off switch, through-hole passives, and a PP3 battery holder.