SI4732 si4735 radio pro mini radio receiver FM MW SW Air Band

SI4732 si4735 radio pro mini radio receiver 2

SI4732 si4735 radio pro mini all band radio receiver FM MW SW Air Band. Upgrade your radio experience with the new version of the SI4732 SI4735 radio pro mini receiver! Experience improved functionality and performance with the latest firmware updates and open-source content. Don’t miss out on the optimized standby power and FM headphone antenna features. Get your hands on the new version files and enhance your listening experience today. Take advantage of the easy station tuning and frequency adjustment modes for seamless operation. Upgrade now and enjoy the ultimate radio experience!

Schematic SI4732 si4735 radio pro mini radio receiver

Schematic Si4732 Si4735 Radio Pro Mini Radio Receiver

Based on the Elf Ball version (V3), a revision was made again. Compared with the previous Elf Ball version, the version differences include:

  1. Merge the main board and expansion board, and modify the PCB to a 4-layer structure.
  2. Package adjustment: some capacitor resistor components are changed from 0603 to 0402, there is a high risk of beginner flipping, please be careful when hand soldering.
  3. The MCU is changed from ESP32S3 module to ESP32 chip and other chips.
  4. The radio chip uses two versions of SI4732 and SI4735.
  5. A complete digital audio solution is used, the 4732 version cannot support analog and digital audio signal output at the same time due to the lack of pins, so the single sideband function is removed, and FM/AM/AIR is retained.
  6. Added Bias-T support.
  7. Replace the magnetic rod coil with an external antenna using an SMA socket.
  8. Band pass filtering circuit and frequency selection circuit (electronic switch is recommended to choose PE4283).
  9. Reduce signal interference and find a way to save power.

Add open source content list:

  • Mini radio schematic and PCB (4-layer structure)
  • Radio new version firmware function description
  • Active FM loop antenna schematic & PCB; When replicating, please do not remove the “designed by hdfy”
  • Label Radio shell & panel design files, by cr@ Sandy Link:
  • All new open-source files contain the keyword [V4], please pay attention to differentiate them from historical open-source files
  • Before purchasing the screws and batteries needed for the shell, please carefully read the instructions in the shell design document.

Latest version files: ESP32_Radio_mini_SI4735_V4_2.4_0908, ESP32_Radio_mini_SI4732_V4_2.4_0908
– Standby power optimization
– FM headphone antenna optimization.

New firmware available for the addition – FW_ESP32S3_Radio_v231004.bin, please download in the attachment.

Buttons from left to right on the top row:
1. LIVE mode
2. UP
4. Theme switch
Buttons from left to right on the bottom row:
5. Clock mode
6. MODE mode
7. SEEK mode
8. FREQ mode

Radio Pro Mini Radio Receiver Screen

Common operations:

  1. Station tuning mode: The screen displays “LIVE” in the middle, and supports saving up to 20 fixed frequencies for easy listening at any time;
    1. Volume adjustment — In LIVE mode, rotate the encoder left and right to adjust the volume level; short press the encoder, mute on/off;
    2. Switch to listen to saved channels — In LIVE mode, short press button 2 to switch to the previous saved channel; short press button 3 to switch to the next saved channel;
    3. In LIVE mode, long press button 2 to turn on/off AGC.
  2. Frequency tuning mode: The screen displays “FREQ/SEEK/MODE” in the middle, supports manual/auto search for stations/switch modulation mode (AM/FM/AIR)
    1. Manual tuning — Short press button 7 to enter SEEK mode, rotate the encoder left and right to automatically search for stations;
    2. Auto tuning — Short press button 8, in FREQ mode, and rotate the encoder left and right to switch the tuning direction;
    3. Save the manually/auto-tuned channels to the station tuning mode for easy listening next time – In FREQ/SEEK mode, long press button 3 to add a new channel; short press button 2/3 to switch to the new/old channel you want to save frequency; long press button 2 to automatically save the found frequency to the current channel;
    4. Switch modulation mode (AM/FM/AIR) — Short press button 6 to switch to MODE mode, long press button 2/3 to switch to the previous/next modulation mode; When MODE displays as AM, short press button 2/3 to switch to the previous/next AM band (MW1/MW2, SW1/SW2, etc.)
    5. Return to station tuning mode, adjust volume, or listen to saved channels—Short press button 1 to return to LIVE mode;

Bandwidth/BFO control is not supported at the moment.

Bom SI4732 si4735 radio pro mini radio receiver

Part Value Description Quantity
R1 620Ω R0402 – SMD resistor 1
R2,R8 100kΩ R0402 – SMD resistor 2
R3,R4,R6 2kΩ R0402 – SMD resistor 3
R5 10kΩ R0402 – SMD resistor 1
R7 150kΩ R0402 – SMD resistor 1
R9,R12,R41,R42 4.7kΩ R0402 – SMD resistor 4
R10 22Ω R0402 – SMD resistor 1
R11 22kΩ R0402 – SMD resistor 1
R13,R17,R19,R20,R25,R28,R33,R39,R45 100 R0402 – SMD resistor 9
R14 NC R0603 – SMD resistor 1
R15,R16,R22,R23,R29,R31,R43,R44 100k R0402 – SMD resistor 8
R21,R34,R35,R36,R37,R38,R40,R46,R47 10k R0402 – SMD resistor 7
R24 20K R0402 – SMD resistor 1
R26 0 R0402 – SMD resistor 1
R27 340 R0402 – SMD resistor 1
R30 10kΩ (103) R0603 – SMD resistor 1
R32 47 R0402 – SMD resistor 1
C1,C3,C6,C9 22uF C0603 – SMD ceramic capacitor 4
C2,C4,C7,C10,C13,C15,C19,C22,C25,C26,C31,C34,C37,C39,C40,C41,C45,C47 100nF C0402 – SMD ceramic capacitor 18
C5 1uF C0402 – SMD ceramic capacitor 1
C8 22nF C0603 – SMD ceramic capacitor 1
C11,C12 220pF C0603 – SMD ceramic capacitor 2
C14 100pF C0603 – SMD ceramic capacitor 1
C16,C18,C30,C42,C43 10nF C0402 – SMD ceramic capacitor 5
C17 3nF C0402 – SMD ceramic capacitor 1
C20,C27,C29 100pF C0402 – SMD ceramic capacitor 3
C21,C33,C35 470nF C0402 – SMD ceramic capacitor 3
C23,C24 2.4nF C0402 – SMD ceramic capacitor 2
C28 330pF C0402 – SMD ceramic capacitor 1
C32 12pF C0402 – SMD ceramic capacitor 1
C36,C38 15pF C0402 – SMD ceramic capacitor 2
C44,C46 10uF C0603 – SMD ceramic capacitor 2
D1 SS34 SMA(DO-214AC) Schottky Barrier Diode 40V 3A 1
D2 TPESD0402G12V 0402 Electrostatic and Surge Protection (TVS/ESD) 1
D4,D5 1N5819WS S4 SOD-323 Schottky Barrier Diode 40V 350mA 2
LCD1 1.47 inch IPS172*320 1.47LCD-IPS-172×320- 12 pin 1
LED1 KT-0603R 0603 SMD red LED 1
Q1,Q3,Q5,Q7, Q9 AP2300 N-Channel SOT-23 MOSFET 20V 5.2A 1.25W 35 mΩ 4
Q2,Q4,Q6,Q8 AP2301 P-Channel SOT-23 MOSFET 20V 3A 57 mΩ 4
U1 AMS1117-3.3 1A Fixed 3.3V Positive SOT-223-3 Linear Voltage Regulator 1
U2 MAX98357AETE+T 3.2Wx2@4Ω TQFN-16-EP(3×3) Audio Power OpAmp 1
U3 TP4054 Polymer 1 500mA SOT-23-5L Battery Management 1
U4 MT3608 Boost converter Type 28V 2V~24V SOT-23-6 DC-DC Converter 1
U5 SI4732-A10-GSR ou SI4735 SOIC-16 or SSOP-24 RF Transceiver IC 1
U6 SI5351A-B11307-GTR 200MHz MSOP-10 Clock Generators / Frequency Synthesizers / PLL 1
U7 ESP32-D0WDQ6-V3 150Mbps 2.412GHz~2.484GHz ADC,I2C,I2S,SDIO,SPI,PWM,UART QFN-48 1
U9 SA602AD or NE602 17dB 5dB SOP-8-150mil RF Mixer 1
U10 ESP-PSRAM64H SOP8-150 mil 64 Mbit SRAM 1
U11 SFECV10M7KA00-R0 330Ω 6dB 110kHz 10.7MHz SMD-3P,6.9×1.5mm Ceramic Filter 1
U12 EC11 Horizontal enconder 1
U13,U14 PE4259 or PE4283 SC-70-6 RF Switch 2
CN1 1.25-2P 1x2Pin 1.25 mm SMD connector 1
CN2 HX25003-2A 1x2Pin 2.5mm XH connector 1
CN3 AUDIO 3.5 mm headphone jack SMD 1
CN4 PROG Pin header 5 pin 2 mm 1
CN5 HC-0.8-6PWT 1×6Pin 6P 0.8 mm SMD Right Angle connector 1
F1 0.1A PTC 9V 200mA 100A 500mA 0603 Resettable Fuse 1
L1 10uH 1.5A 0420 Power Inductor 1
L2 RFANT5220110A2T Ceramic antenna 2×5.2 mm 1
L3 1uH 0603 – SMD inductor 1
L4,L5 56nH L0402 – SMD inductor 2
L6,L7 680nH L0603 – SMD inductor 2
L8,L10 15nH L0402 – SMD inductor 2
L9 4.7nH L0402 – SMD inductor 1
L11,L12 10uH L0806 – SMD inductor 2
L13 270nH L0603 – SMD inductor 1
L14,L15 SZ1608K252TF 0603 Ferrite Bead – 1.2 Ω 2.5 kΩ@100MHz 2
RF1 BWSMA-KE-P001 SMA Board Edge Offset feet RF connector 1
RN1 4.7 kΩ (472) 0603×4 Resistor Network 1
SW1 RESET SMD 3.5×7.8 mm Tactile Switch 1
SW2 FUN1 SMD 3.5×7.8 mm Tactile Switch 1
SW3 FUN2 SMD 3.5×7.8 mm Tactile Switch 1
SW4 FUN3 SMD 3.5×7.8 mm Tactile Switch 1
USB1 KH-TYPE-C-16P 16 pin Type-C SMD USB Connector 1
X1 25MHz SMD3225-4P Crystal 1
X2 40MHz SMD3225-4P Crystal 1

Download files and info

Si4732 Si4735 Radio Pro Mini Radio Receiver

Download PCB in Gerber + esp32 Firmware

Download Gerber

Download ESP32S3 Firmware

Download 3D housing

Files you will use

  • FW_ESP32S3_Radio_v231004.bin — Firmware for ESP32
  • — Gerber for SI4732
  • — Gerber for Si4735
  • 外壳3D打印文件V4bySandy — 3D case

Buy components for this project


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About the author blog author. Electronics technician for the technical school of Brasilia - Brazil. Interested in electronics, circuits and technology in general.

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