• Has battery charger built in
• Amazon Reviewer says to use ESP32 Arduino → WEMOS LOLIN32 board
  • Arduino ESP32 can be installed via the Board Manager
    • does not contain Lolin Board
  • esp32 by Espressif in the Board Manager is the right choice
    • contains WEMOS Lolin32 Lite
    • can be selected in Tools → Board
    • get Board Info does not return anything useful?

On-Board LED Blinking works:

#define LED_PIN 22   // Pin number for your built-in LED
 
void setup() {
  pinMode(LED_PIN, OUTPUT);  // Set the LED pin as an output
}
 
void loop() {
  digitalWrite(LED_PIN, HIGH);  // Turn the LED on
  delay(500);                   // Wait 500 milliseconds
  digitalWrite(LED_PIN, LOW);   // Turn the LED off
  delay(500);                   // Wait 500 milliseconds
}

• Wiki Entry
  • We probably can connect our speaker directly to the SPK pins
  • We can read the BUSY line to know if something is playing
    • high = busy
  • There are three modes.
    • We probably want to use the Serial Mode to directly play a certain file
      • this means we connect the UART pins between the ESP and the Player
    • Theres sample code in the wiki
  • Filenames: /MP3/0001.mp3
• Github Repo for Arduino Lib
  • Arduino IDE has “DFRobotDFPlayerMini” in the list of libraries
    • alternatively one seems to be able to download the zip from github and simply add it via Sketch → Include Library → Add .ZIP library
  • There are a whole bunch of other libraries when you search for DFPlayer…
    • some of them seem to be newer than the original
    • some of them might make handling other stuff while playing sound easier

• Lots of Details at Adafruit
• We want to connect to this via the i2c bus
• There's an ADXL345 Library by Adafruit, but also by others

3.3V ── LDR ──+─── GPIO34 (A0)
               │
             10kΩ
               │
              GND

we're not using this one

• I bought B00EFOTJZE these
• I think we should be able to simply connect them to two GPIO pins
  • actually the emitter can probably be just powered permanently
    • not sure if I need a resistor, the Amazon page contains really shitty translations
    • I should hook up one of the diodes to my component tester
    • actually based on the given foward voltage and current, according to an online calculator I need resistor of about 70ohm
• The sensor is a VS 1838B

   _____
  |     |
  |     |
  |     |
  |     |
  |_____|
   | | |
   1 2 3

1: OUT (Signal)
2: GND
3: VCC (typically 3.3–5V)