ESP32 Music Ambient Light

I. Main Functions
1. Picks up external audio sources via an I2S microphone, performs FFT transformation, and drives the TFT display and WS2812B LED board for music spectrum display. Spectrum mode, sensitivity, and brightness can be adjusted via buttons.
2. Creates images on a 16*16 pixel canvas via the TFT and touchscreen, and displays them on the WS2812B LED board.
3. Decodes MP3 files and outputs them to the I2S amplifier circuit for audio playback.
II. Circuit Design
1. The main control uses the ESP32-WROOM-32 module, which is easy to solder. Furthermore, the ESP32 supports almost all IO mappings, so there's little need to worry about IOs not working for certain functions.
2. Audio input uses an I2S microphone; here, the ICS43434 is used, which is much more sensitive than the previously used INM441.
3. Audio output uses the NS4168 chip, which supports I2S and can drive a maximum 4-ohm 2.5W speaker. The main reasons for choosing this chip are: 1. Simple soldering of the 8-pin chip, fewer external components, and easy integration onto the board;
2. Audio playback files are stored on an SD card and connected to the main controller via an SPI interface;
3. The resistive touchscreen and TFT are connected to the main controller via a shared SPI interface;
4. A five-way joystick button is connected to IO034353639 to implement button control function;
5. An LED is used to indicate the power status;
6. A tactile switch is used to reset the system;
7. An automatic download circuit is designed using CH340C for easy development;
8. The power supply uses TYPE-C for direct 5V supply, and the onboard AMS1117 provides 3.3V power;
9. Considering the free prototyping size, a 65mm*65mm LED board was designed, which can be used to panelize four boards.
III. Program Design
The program uses Arduino IDE
. 1. The interaction method combines touchscreen and button input (touchscreen sampling affects the main process). The touchscreen and TFT share VSPI.
2. The SD card module uses HSPI independently.
3. The I2S microphone and I2S amplifier chip use independent I/O interfaces, each occupying 3 I/O pins.
IV. Appearance Design
The casing uses LCSC EDA design. It consists of a lamp board casing and a main control casing. The main control casing can be directly embedded into the back of the lamp board casing, making it a single unit. The front panel of the lamp board uses LCSC's panel. Below is a picture of the actual product. Due to the reversed grid offset and antenna hole positions mentioned later, the picture below is not a single unit.
The main control unit, housing
, light board, panel light board, and main control unit
are combined. V. Function demonstration (see video below). VI. Existing problems : 1. The audio output chip enable pin is directly connected to the VBUS input. Therefore, when this module is not used, there may be speaker noise and power consumption issues. If the TFT backlight control is not used later, the above pins can be used to enable the NS4168. 2. In the first version of the design, only pins 34, 35, 36, and 39 were mentioned as input pins, so they were used for button control. It was found that these pins did not have pull-up resistors, causing the button reading to always be low voltage. This was solved by using jumper wires, and the circuit diagram was upgraded by adding pull-up resistors. 3. Considering the limited board space, the TFT used has a soldered interface, but incomplete soldering can easily lead to malfunctions in the touch function. The PCB board can be used to press down the FPC for soldering to prevent cold solder joints. 4. Two problems were also encountered in the housing design. One issue is that the assembly tolerance in the design of the light board housing is too small, causing the light board to be unable to fit into the light board grille. This can be resolved by grinding the grille holes. Another issue is that the front and back of the light board housing and the main control housing were not clearly distinguished during the design process. This resulted in the pre-drilled holes for the onboard PCB antenna on the light board housing being reversed (it should have been offset to the left, but it was offset to the right, a difference of 6mm). This prevented the main control unit from being fully inserted into the light board housing. This has been corrected in the housing design file. 5. The misalignment of the antenna holes and the use of a free font library to generate the bin file caused occasional missing MP3 file names when actually displayed.