104 lines
2.1 KiB
Markdown
104 lines
2.1 KiB
Markdown
# HannaBox
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## Microcontroller
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We are using an ESP-WROOM-32 module. For the mp3 decoding we need a multicore CPU, be careful, there are some ESP32 with only one core.
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## Pins
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The plain number refers to the GPIO pin.
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### Amplifier
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MAX98357A I2S 3W DAC Class D Amplifier Module
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```
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26 -> DIN
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27 -> BCLK
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25 -> LRC
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5V -> Vin
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GND -> GND
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```
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### SD Card Reader
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SD Card Reader Adapter Modul
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```
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CS -> 22 (D1)
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MOSI -> 23 (D7)
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CLK -> 18 (D5)
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MISO -> 19 (D6)
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```
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### RFID Reader
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NFC RFID module RC522
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```
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SOA -> 32
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SCK -> 18
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MOSI -> 23
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MISO -> 19
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IRQ -> NC
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GND -> GND
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RST -> 33
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3.3V -> 3.3V
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```
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#### RFID Chip Registers
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Interrupt method was not working because it seems reading a card does not trigger one.
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See https://arduino.stackexchange.com/a/76285 and https://github.com/miguelbalboa/rfid/blob/master/examples/MinimalInterrupt/MinimalInterrupt.ino
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### Buttons
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```
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Start / Stop -> 17 and GND
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Wake up / Next -> 04 and GND
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Previous -> 16 and GND
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```
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## Battery Voltage
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The battery voltage is measured by the ADC of pin 35. A voltage divider halves the voltage so that the pin can not be overloaded (max 3.3V).
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The voltage divider consists of two 100kOHM resistors, the voltage is measured between them. One side is connected to the battery and the other to ground.
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There are 2 ADCs, make sure to not use the one which is not usable during WIFI!
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## Power
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We use the voltage regulator of the SD Card module. We also can use a LDL1117S33R Low Dropout Voltage regulator. For Loading the LiIon we can use a LTC4054 or a dedicated module.
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## System sounds
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Place these sounds in the folder `system` on the SD card:
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* sleep.mp3
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* start.mp3
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sleep.mp3 will be played just before the timed shutdown, start.mp3 will be played if the box started and initialized successfully.
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## TODOs
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## Schematic without modules
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### Charging circuit
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https://ww1.microchip.com/downloads/en/AppNotes/01149c.pdf
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MCP73837 ?
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## Links
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https://github.com/earlephilhower/ESP8266Audio
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[Running two SPI devices at once](https://randomnerdtutorials.com/esp32-spi-communication-arduino/)
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