CH32V003 FM Radio Receiver

# CH32V003 FM Radio Receiver with RDS With the portable Li-Ion battery powered FM radio receiver you can listen to your favourite radio station. This device is equipped with cost-effective components, including a CH32V003J4M6 32-bit RISC-V microcontroller, a RDA5807MP FM radio tuner IC, an audio amplifier (TC8871 or XPT8871), a 128x32 pixel OLED display (SSD1306), and a Li-Ion battery charger (TP4054 or MCP73831). You can directly connect a protected 3.7V LiPo battery, a 3W / 4Ω speaker, and an FM antenna. The FM Radio Receiver is a port from the [ATtiny412 version](https://github.com/wagiminator/ATtiny412-PocketRadio). - Project files and firmware (Github): https://github.com/wagiminator/CH32V003-FM-Receiver  # Hardware ## Schematic  ## The CH32V003 Family of 32-bit RISC-V Microcontrollers The CH32V003 series is a collection of industrial-grade general-purpose microcontrollers that utilize the QingKe RISC-V2A core design supporting the RV32EC instruction set. These microcontrollers are equipped with various features such as a 48MHz system main frequency, 16KB flash, 2KB SRAM, wide voltage support, a single-wire serial debug interface, low power consumption, and an ultra-small package. Additionally, the CH32V003 series includes a built-in set of components including a DMA controller, a 10-bit ADC, op-amp comparators, multiple timers, and standard communication interfaces such as USART, I2C, and SPI. ## RDA5807MP FM Radio Tuner IC The low-cost RDA5807MP is a single-chip broadcast FM stereo radio tuner with fully integrated synthesizer, IF selectivity, RDS/RBDS, and MPX decoder. The tuner uses the CMOS process, support multi-interface, and require the least external component. All these make it very suitable for portable devices. The RDA5807MP is controlled by the microcontroller via I²C. ## TC8871 Audio Amplifier IC The TC8871 is an FM-free, Class AB/Class D selectable power amplifier. When the working voltage is 5V, the maximum driving power is 5W (2Ω, BTL load, THD>10%). The application circuit of TC8871 is simple, only a few peripheral devices are needed, and the feedback resistor is integrated; the output does not need an external coupling capacitor or a power-up capacity and buffer network. The amplification can be selected via the value of the resistors R3 and R4 (Gain = 2 * 100kΩ / (10kΩ + R3), R4 respectively), which determines the maximum volume. Keep in mind that the resistors together with the coupling capacitors C3 and C4 form a high-pass filter whose cut-off frequency is determined using the following formula: f = 1 / (2 * π * R3 * C3), R4 and C4 respectively. ## TP4054 Li-Ion Battery Charge IC For battery charging the TP4054 is used. The TP4054 is a complete constant-current/constant-voltage linear charger for single cell lithium-ion batteries. Its small package and low external component count make the TP4054 ideally suited for portable applications. The constant current value is set with one external resistor (I = 1000V / R6). Charging is done via the built-in USB-C connector. The TP4054 can be replaced by a MCP73831. ## ME6209A33 3.3V Linear Voltage Regulator The ME6209 series are a group of positive voltage output, three–pin regulator, that provide a high current (max 250mA) even when the input/output voltage differential is small (80mV dropout voltage). Low power consumption (3µA quiescent current) and high accuracy (+/-2%) is achieved through CMOS technology. They allow input voltages as high as 18V.  # Building Instructions Solder all components to the PCB. Place the 40mm speaker in the corresponding cutout on the board. Glue the speaker in place with hot glue. Make sure that the glue is airtight all around to achieve good sound quality. Solder the connection cables between speaker and board. Solder the wire antenna to the corresponding pad on the board. A 75cm (30" = λ / 4) long 28AWG flexible silicone insulated wire works very well.  3D print the case. Cases with different heights are available in the "3dprint" folder. Choose the case that matches the height of your battery and speaker. Glue the battery into the case with double-sided tape. Thread the wire antenna through the small hole in the housing. To improve the sound quality, you can pack a foam mat between the battery and the PCB inside the case. This should fit snugly against the outer walls of the housing.  Connect the battery to the JST connector on the board. Pay attention to the correct polarity, unfortunately there is no standard here! At the latest now you should upload the firmware. Use the PROG pads on the board for this. Place the board on the case and screw it with four M2x5mm self-tapping screws.  There are different loudspeakers with 40mm diameter. The flatter ones allow the radio to be built more compactly, while the taller ones have better sound quality.   The size of the battery also affects the size of the radio. In operation, the radio consumes around 100mA - 125mA at 3.7V and medium volume. So a battery with a capacity of 1200mAh should provide around 10 hours of playtime.  # Operating Instructions 1. Make sure that the wire antenna is laid as straight as possible horizontally or vertically. 2. Turn on the radio using the power switch. 3. Use the volume buttons to select the volume from 0 to 15. 4. The next station is searched for with the "CH+" button. 5. When the OLED shows "Bat: weak", you should soon recharge the battery via the USB-C port.  If there's no radio station nearby and/or you want to build one yourself, take a look [here](https://github.com/wagiminator/CH32V003-FM-Transmitter). # References, Links and Notes - [EasyEDA Design Files](https://oshwlab.com/wagiminator) - [CNLohr: ch32003fun](https://github.com/cnlohr/ch32v003fun) - [WCH: CH32V003 datasheets](http://www.wch-ic.com/products/CH32V003.html) - [WCH: WCH-Link user manual](http://www.wch-ic.com/downloads/WCH-LinkUserManual_PDF.html) - [WCH: Official Store on AliExpress](https://wchofficialstore.aliexpress.com) - [RDA5807MP Datasheet](https://datasheet.lcsc.com/lcsc/1806121226_RDA-Microelectronics-RDA5807MP_C167245.pdf) - [TC8871 Datasheet](https://datasheet.lcsc.com/lcsc/2202252130_Shenzhen-Fuman-Elec-TC8871_C89482.pdf) - [TP4054 datasheet](https://media.digikey.com/pdf/Data%20Sheets/UTD%20Semi%20PDFs/TP4054.pdf) - [ME6209 Datasheet](https://datasheet.lcsc.com/lcsc/1811081822_MICRONE-Nanjing-Micro-One-Elec-ME6209A33M3G_C83508.pdf) - [SSD1306 Datasheet](https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf) - [ATtiny13A TinyPocketRadio](https://github.com/wagiminator/ATtiny13-TinyPocketRadio) - [ATtiny85 TinyFMRadio](https://github.com/wagiminator/ATtiny85-TinyFMRadio) - [ATtiny412 FM Pocket Radio](https://github.com/wagiminator/ATtiny412-PocketRadio) - [CH32V003 FM Radio Transmitter](https://github.com/wagiminator/CH32V003-FM-Transmitter) - [128x64 OLED on Aliexpress](http://aliexpress.com/wholesale?SearchText=128+64+0.96+oled+new+4pin) # License  This work is licensed under Creative Commons Attribution-ShareAlike 3.0 Unported License. (http://creativecommons.org/licenses/by-sa/3.0/)