Sound level meter for workplace with additional features
- continuous measure of the sound level, use standard decibel scale
- average values from last measures
- display warning when configured level is exceeded
- support IR remote controler for configuration and mode change
- powered by standard type A USB adapter 5V 2A
- display settings (brightness, rotation, mode) and noise limit are stored to non-volatile flash memory, persist after reboot or power loss
- wifi-manager supported, when connection to last wifi settings fails, switch to Access Point mode and provide interactive web page settings on 192.168.4.1
- automatic time synchronization using Network Time Protocol with correct STD/DST time shifting for central Europe
- periodical check of new firmware versions from server and automatic download and OTA update when found
- when the configured noise level is exceeded, call Google Web-app with current average, chip id, firmware version and local time - will write log entry in Google Sheet
- ESP32 WROOM development module with basic 4MB Flash, without additional PSRAM
- digital MEMS microphone module INMP441 with I2S Interface
- Flexible Led Panel WS2812B RGB matrix 8x8 pixels
- IR receiver VS1838B
- IR Remote Control BN59
- Self locking switch button 8.5 x 8.5 mm (power-on/off)
- Single row pin header strip (module sockets)
- 2 wire red-black cable 20AWG (power supply line)
- Universal double sided PCB board 8x6 cm
- Universal double sided PCB board 8x2 cm
- 6 pin IC socket (for microphone module)
- Type A Male USB 4 Pin Plug Socket Connector With Black Plastic Cover (power supply line)
- Steel Small Phillips Flat Cross Round Head Self-tapping Screw M2
- 10 pin flat color ribbon cable
- Resistor 330 Ohm 0.5W
- Aluminum Electrolytic Capacitor 330uF 6.3V
- 3D printed case, base + lid connected together using presision snap joins (open scad files in resources directory)
- hole for power supply line
- PCBs mounted on 3d printed standoffs using screws
- PCBs electrically connected together using flat ribbon cable, soldered, no connectors
- small PCB contains sensors (microphone, IR) and power switch, peeks out through case holes
- large PCB contains microcontroller and other modules
- translucent window made from two layers of transparent foils and lawyer of white paper between foils
- led panel is fixed behind window with hotglue and connected with PCB using 3 pin wire with connector
