A quick update on the prototype

A project log for NFC Bose Wave Player

An NFC-enabled music player designed for kids to be able to pick their songs, built the hardest way possible

gilphilbertgilphilbert 07/11/2021 at 06:080 Comments

This is my current prototype with all through hole components (except the ESP32-WROOM-32U which only comes in castellated form). This shows the PCB in the enclosure:

You can see the larger heatsink (it says "PAT. PENDING" on top), the amplifier stage at the rear, the ESP32 at the front and the SD card reader on the right. At the front is header for the connection to the front panel. That thing hanging from wires is the DAC module - as the header is around the wrong way, I had to use dupont connectors to get it working. In this model, you can see the empty footprint where the DS logarithmic potentiometer was. I've removed it since I've discovered the ESP32 can control the gain of the DAC directly in software. It doesn't go super-quiet (think whisper quiet) but my kid will be rocking out to this, so that's OK for my purposes. I need to cut a chunk out of the battery bay so it will be possible to change the SD card without taking the lid off - simply removing the battery cover will provide access.

This one shows the unit a little more assembled:

The thing hanging off from the left is the PN532 NFC card reader. It's connected via I2C and uses interrupts. Hidden behind the OLED is an ATtiny 841 that powers the (currently missing) button pannel. I only have one connector for the button panel and I don't want to ruin it, so I won't solder it on until the top board is final. At this point, you can scan a card and it will play a song!