The PM2.5 Monitor is a portable device that can measure and detect the concentration of atmospheric particulate matter (PM) of less than 2.5 micrometers in real-time. The density is displayed on an LCD panel with LED indicators to show the air quality. It also has a charging and power supply function as a mobile battery, and displays battery capacity with four LEDs. If the preset concentration threshold is exceeded or the battery voltage drops below 2.8V, it will inform you with a buzzer.
This solution features the RL78/L12 low power consumption, compact LCD MCU which includes functions such as I/O port, A/D converter, buzzer, LCD controller, STOP mode, etc. The device is best suited for small home appliances. In addition, the ISL97656 (DC/DC converter IC) controls battery discharge and the ISL6294 (battery charger IC) controls charging. The threshold value and PM2.5 concentration data are saved in EEPROM (if the data amount is less than 2KB, you may also use the data flash built in RL78/L12).
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- Demo board includes the RL78/L12 MCU
- When the outside PM2.5 concentration value is larger than the pre-set value, the buzzer (about 80dB) will sound at 1s intervals
- When the battery is low, the buzzer (about 80dB) will sound at 2s intervals
- If the battery is charging, the charge indicator light will stay on and the battery remaining indicator light will steadily blink
- If the charging is complete, the charge indicator light will stay off and the battery remaining indicator will display normally
- Battery remaining indicator: Different status of the 4 LED lights show the remaining battery amount