Yet Another Internet Radio

Internet radio derivative from the open source project Yoradio. Its main part is a 2.8" CYD (Cheap Yellow Display). The second main part is custom I2S audio amplifier board. The whole electronics part is placed in a small plastic box. The radio can drive up to 24W in 4 Ohm speaker. The supply range starts from 5V to 14V.

The design is not complicated. When using an assembled amplifier board, it is matter of few wire connections. Under desire the amplifier board can be assembled by yourself. The gerbers files are available for download.

Supplies

2.8" CYD (Cheap Yellow Display) - widely available in Aliexpress, eBay, Amazon..etc. Can be used different size.
I2S audio codec amplifier board - can be purchased ready assembled from Tindie or assembled by yourself. In the second case you would need the PCB from PCBway and the TPA316D2 amplifier board (shown on the last picture and available again in the online shops listed above)
5V buck converter board
Plastic box (Aliexpress, size of the box used : 120mmX80mmX40mm)
Push ON/OFF button (can be with or without LED)
4 (two colours) 4 mm brass banana plugs for amplifier and speaker terminals
locking two pin wire connector
3 pin PCB 2.54mm wire connector
DC power connector

If you want different then grey plastic view, you would need some paints for the box. I used a special hammer blow spray paint and another white gloss one for the front panel.

CYD Preparation

As first step I flashed the CYD (it contains embedded ESP32 board). How to do this is described here.

From your side you only have to define some parameters in the file "myoptions.h" preliminary. They depend on the LCD you are using, the connections between the ESP32 and your I2S codec, language used...etc.

Here are some explanations:

#define L10N_LANGUAGE RU - allows the use of cirilyc letters on the LCD

#define DSP_MODEL DSP_ILI9341 - defines the type of the LCD controller.

You have to check your CYD which controller uses and to write it there

#define TFT_DC 2

#define TFT_CS 15

#define TFT_RST -1

#define LED_BUILTIN 17

#define BRIGHTNESS_PIN 21 - typical settings for the CYD. Check the circuit of the CYD,

provided as download by the seller if they are the same. Nprmally they should not differ.

#define TS_MODEL TS_MODEL_XPT2046

#define TS_CS 33

#define TS_SPIPINS 25, 39, 32 /* SCK, MISO, MOSI */

#define IR_PIN 27

#define LIGHT_SENSOR 34

#define AUTOBACKLIGHT_MAX 1024 - normally standard setting for CYD.

If something is not working you have to compare again with the schematic

And the most important:

#define I2S_DOUT 22

#define I2S_BCLK 16

#define I2S_LRC 4 - Define the pins of ESP32 used for I2S communication. They are

on your choise. I used these, because the CYD does not have a lot of free pins.

The flashing procedure can be followed in the Yoradio project site.

The setup procedure is also described here. (Do not use the available compiled binary file provided there for flashing. It does not support the LCD and the I2S connections are different)

After programming if the CYD, it has to be wired : the supply and I2S connections.

For the power supply (5V) wire I removed the protection diode D1 (close to the USB connector) and bridged it with red 18AWG wire. The ground wire I soldered on a GND board test point (see the picture).

The I2S wires were soldered directly on the ESP32 pins ( IO 22, 16,4) in the following order:

DOUT 22

BCLK 16

LRC 4

I fixed them additionally with hot glue to make them stable.

To save some power I removed the resistors R17, R20, which are used for current limiting of the RGB LED connected to the pins 16 and 4.

The power supply wires coming from the CYD I soldered at the output terminals of the 5V buck converter.

After whole this preparation work I tested the whole assembling by the use of small I2S custom board. It was working perfect.

Downloads

myoptions.h

Amplifier Board Assembling

The amplifier board contains two main parts:

Custom PCB
TPA3116D2 amplifier board

The PCB was produced by PCBWAY in a very short time - I have to wait only ten days after I have ordered the boards to receive them. The quality of the production is very high. Making an order at PCBWAY is very reliable. With each order you accumulate bonus points. You can use after that them to purchase some electronics parts, modules, sensors ..etc. from their gift shop. Some of the modules are even payless. You can download the gerber files from there or to make directly order. All information about the board (schematic, BOM is available for download)

Another possibility is to buy ready made assembled board including the power amplifier from here.

Downloads

pcm5102.pdf

Housing Preparation

I started with a cutting oh hole for the LCD on the top cover of the box. A hand rotary tool was used for that purpose. I filed and sanded the opening. The cut piece I kept for further use.

After cutting the opening for the LCD I painted the box. I painted also the front and bottom panels in different colours.

I used the cut plastic piece for the holder of the amplifier board. I mounted inserting nuts on it and glued to the bottom of the lower part of the box.

Assembling of the Radio

The speakers connectors I mounted on the back panel.

The amplifier board I fixed with screws on the holder

On the front panel I mounted the power switch and power supply connector

Two supply wires for the LCD with mounted on the locking connector I soldered in the following way:

The GND (blue one) was connected to the negative terminal of the DC connector.
The input power supply (the red one) I soldered after the power switch.

The CYD i fixed with a hot glue on the top part of the box.

Everything Is Ready

Finally the box was closed and connected with the speakers. For suppling of the radio I used 12V 3A power adapter. With it the radio is enough strong to drive two 10W 4 Ohm speakers without any lose of sound quality.