Making a bus stop bell using Arduino

• Playing WAV bell sounds from SD card with real button
• Select various sounds with button switch and OLED screen
• Use independently with Lithum battery pack / charging module, no power cable needed

• Bus stop bell button
• Arduino Nano or compartible board (as small as possible / better to avoid ESP8266 because of TMRpcm library compartibility issue)
• SD card module
• SD card
• Speaker and amp module (over 0.5W 8ohm. Piezo or small buzzer may not work)
• OLED screen (SSD1306 or whatever I2C you want)
• Lithum battery pack and charging module (each of two needed for over 5V power)
• Push tact button (for sound select)
• Slide switch (for power on/off)
• Perfboard (proper size for your case)
• Plastic case shell