USB CO2 Air MonitorCompact USB-powered desktop CO₂ air quality monitor using an NDIR CO₂ sensor, microcontroller, OLED display, and visual good/moderate/poor status indication.ziliani2 days ago·Star
9V LED BlinkerHand-solderable 9V battery-powered red LED blinker using a 555 timer, on/off switch, through-hole passives, and a PP3 battery holder.ziliani2 days ago·Star
