The ATS MINI RADIO ESP32-S3 SI4732 Pocket Radio DSP Receiver represents a sophisticated fusion of modern microcontroller technology and advanced digital signal processing for radio reception. This compact, feature-rich device leverages the powerful ESP32-S3 microcontroller combined with the Silicon Labs SI4732 DSP radio chip to deliver comprehensive multiband radio capabilities in a highly portable form factor.
Core Hardware Architecture
ATS MINI RADIO ESP32-S3 Microcontroller Platform
The system is built around the Espressif ESP32-S3-WROOM-1-N16R8module, which provides:
- Dual-core LX7 processors operating at up to 240 MHz
- 16 MB Flash memory for firmware storage and user data
- 8 MB PSRAM for smooth operation and buffer management
- Integrated Wi-Fi 802.11 b/g/n with 2.4 GHz support
- Bluetooth 5.0 LE for wireless connectivity options
- Advanced GPIO capabilities for peripheral interfacing
- Low power consumption optimized for portable applications
The ESP32-S3 serves as the central processing unit, handling user interface management, frequency control, audio processing, and communication with the SI4732 radio chip via I2C protocol.
SI4732 Digital Signal Processing Radio Chip
The heart of the ATS Mini radio functionality is the Silicon Labs SI4732-A10-GS DSP receiver chip, which offers:
Frequency Coverage:
- AM/MW (Medium Wave): 520 kHz to 1710 kHz
- LW (Long Wave): 153 kHz to 279 kHz
- SW (Short Wave): 2.3 MHz to 26.1 MHz
- FM: 64 MHz to 108 MHz with RDS support
Advanced DSP Features:
- Digital Signal Processing for superior audio quality and noise reduction
- Automatic Gain Control (AGC) for consistent signal levels
- Bandwidth filtering with selectable options (0.5, 1.0, 1.2, 2.2, 3.0, and 4.0 kHz)
- Beat Frequency Oscillator (BFO) for SSB demodulation
- Signal strength indication (RSSI) for tuning assistance
- Low power consumption design for battery operation
Modulation Support:
- AM (Amplitude Modulation) for standard broadcast reception
- SSB (Single Sideband) with both USB (Upper Sideband) and LSB (Lower Sideband) modes
- FM (Frequency Modulation) with stereo capability and RDS data decoding
ATS Mini – Display and User Interface
1.9-inch IPS Display System
The device ATS MINI features a 1.9-inch ST7789 IPS display with the following specifications:
- Resolution: 170 × 320 pixels
- Color depth: 16-bit (65,536 colors)
- Viewing angles: Wide angle IPS technology
- Brightness: High brightness for outdoor visibility
- Interface: 30-pin connector with SPI communication
The display provides a comprehensive user interface showing:
- Current frequency with precise digital readout
- Operating mode (AM/FM/SSB/LSB/USB)
- Signal strength meter
- Battery status indicator
- Bandwidth and filter settings
- Volume and gain controls
- Menu navigation system
Control Interface
The radio incorporates multiple control mechanisms:
Physical Controls:
- EC11 10mm rotary encoder for frequency tuning and menu navigation
- Tactile buttons for mode selection and function access
- Power switch integrated into the design
Software Interface:
- Intuitive menu system with graphical elements
- Touch-sensitive areas (depending on variant)
- Customizable display layouts
- Frequency memory presets
ATS Mini – Audio System Architecture
Audio Processing Chain
The audio subsystem consists of several components working in concert:
Digital Audio Processing:
- SI4732 performs initial digital filtering and demodulation
- ESP32-S3 handles additional audio processing and volume control
- Digital-to-analog conversion within the SI4732 chip
- Audio amplification stage for speaker and headphone output
Audio Output Options:
- Built-in speaker: 1511 series, 8 ohms, 1W power rating
- 3.5mm headphone jack for private listening
- External speaker connection capability
- Line output for connection to external audio systems
Audio Quality Features:
- Low distortion digital signal processing
- Noise reduction algorithms
- Automatic volume control options
- Bass and treble adjustment (software-controlled)
ATS MINI RADIO – Power Management System
Battery Technology
The ATS MINI utilizes a lithium-ion 603040 battery with the following characteristics:
- Capacity: 800 mAh typical
- Voltage: 3.7V nominal
- Battery life: Approximately 10+ hours of continuous operation
- Charging: USB-C charging interface
- Protection: Built-in battery management system
Power Consumption Optimization
The device implements several power-saving features:
- ESP32-S3 sleep modes for reduced power consumption during standby
- SI4732 power management with automatic shutdown of unused circuits
- Display brightness control for battery life extension
- Automatic power-off after period of inactivity
- Low battery warning system
ATS Mini – Software Architecture and Firmware
Open Source Foundation
The ATS MINI runs on open-source firmware developed by the radio enthusiast community:
Primary Firmware:
- Based on Ralph Xavier’s ESP32 OLED_ALL_IN_ONE sketch
- PU2CLR library integration for SI4732 control
- Arduino IDE compatibility for easy modification
- GitHub repository availability for community development
Key Software Features:
- Multi-language support with internationalization
- Frequency memory banks for storing favorite stations
- Band scanning capabilities
- RDS data decoding for FM stations
- Signal strength logging and analysis
- Firmware update capability via USB or OTA
Programming Interface
The device supports multiple programming and customization options:
Development Environment:
- Arduino IDE with ESP32 board support
- PlatformIO compatibility for advanced development
- Visual Studio Code integration
- Command-line tools for batch operations
Customization Options:
- Pin configuration changes for different hardware variants
- Display layout modification for personalized interface
- Audio processing parameters adjustment
- Power management settings optimization
Connectivity Features
The ESP32-S3 platform enables advanced connectivity options:
Wireless Capabilities:
- Wi-Fi connectivity for internet radio streaming (with appropriate firmware)
- Bluetooth audio streaming for wireless headphones
- Over-the-air updates for firmware maintenance
- Remote control via smartphone applications
- Data logging to cloud services
Video – ATS Mini ESP32 receiving amateur radio HF NET
ATS Mini – Real User Reviews with Proper Attribution
Detailed Review from “Blog or Die!”
Reviewer: Anonymous blogger at blogordie.com (Spain trip, May 2025)
Overall Assessment: The reviewer notes “This is definitely a higher build quality product” when comparing the V3 model to earlier versions.
Build Quality Improvements: The reviewer observed that “the box wasn’t half crushed like the prior one, and the instructions seem professionally printed. The case fits together without a big crack.”
Audio Performance: “I think the speaker may sound a touch better, but good headphones made a big difference” – indicating that while the built-in speaker is adequate, the device really shines with quality headphones.
Firmware Evolution: The reviewer tracked firmware updates from V1.01 to version 2.27, showing active development. They noted significant improvements with version 2.23 that “appears to support Wi-Fi to get the precise time”.
Critical Issues Identified:
- Cable Compatibility: “Many USB C cables only charge and cannot transmit data. Grrr.” – A practical frustration for firmware updates.
- Documentation Problems: “I should finish reading the manual because I clearly don’t understand Wi-Fi on this device” – suggesting the manual could be clearer.
- Version Compatibility: “My older one is described as V1 and may not run the latest firmware” – indicating potential upgrade limitations for early adopters.
Standout Features: The reviewer was particularly impressed with the EiBi integration: “The EiBi integration is a wonderful addition! I’ve been enjoying it for the last few days” and “So now when I tune the frequencies, possible stations on that frequency cycle at the bottom of the screen. How cool is that?”
EEVblog Forum Discussion
Source: EEVblog Electronics Community Forum – SI473x based radios thread
User Feedback: One forum member noted a technical limitation: “Personally like the one with mixer stage in front, because do not like clicking sound of kHz frequency change on Si437x chipset” – indicating that some users find the stepping noise during frequency changes to be objectionable.
Development Status: “Have here at hand one chip and pcb adapter and few arduino-s, but no free time to start experimenting” – showing that even experienced electronics enthusiasts are interested in the platform but may need time to fully evaluate it.
Technical Community Feedback
Developer Attribution: Based on documentation, the project benefits from contributions by:
- Ralph Xavier: Original port developer
- PU2CLR (Ricardo Caratti): ESP32 OLED_ALL_IN_ONE sketch contributor
- Volos Projects: FM Radio project contributor
- Dave (G8PTN): Alternative firmware developer
- Sunnygold: Hardware design contributor
Antenna Performance Discussion
Practical Observation:“Discussions online suggest that the Red donut antenna has a higher impedance than the Black one, and may be suited for the V3 ATS-Mini while the Black one might be better for the V1 model. Testing required.”
This indicates that antenna matching is still being optimized and may require user experimentation for best results.
Firmware Development Trajectory
Version History: The active development is evident from the firmware progression:
- V1.01: Initial release
- V2.23: Added Wi-Fi time synchronization
- V2.26: EiBi integration
- V2.27: Current version (as of review)
User Interface Improvements: “V2.23 also adjusts the boundaries of some of the bands. Long fixed is the two MW2 bands, and all the numbered SW bands are replaced by meter bands. There is now an option to show additional FM RDS information.”
Practical Usage Challenges
Wi-Fi Setup Complexity: The reviewer documented a multi-step process for Wi-Fi configuration: “Put the ATS Mini in Access Point mode, Connect to its Wi-Fi network with a device, Access 10.1.1 in a browser, Fill in the name and password of the network” – suggesting the setup process could be more user-friendly.
Time Synchronization Requirements: “The radio stores the schedule in flash memory, but to use it requires that the radio know what time it is, and that only happens with RDS data or connection to Wi-Fi and an NNTP server” – indicating a dependency that may limit some features in areas with poor RDS coverage.
Quality Control Variations
Version Differences: The reviewer’s experience shows significant quality improvements between versions, with “higher build quality product” in V3 compared to earlier versions, but also notes compatibility issues where older versions “may not run the latest firmware”.
User Experience Summary
Positive Aspects (per cited reviewer):
- Improved build quality in newer versions
- Active firmware development with meaningful feature additions
- EiBi integration provides practical value for shortwave listening
- Better audio with quality headphones
- Professional packaging and documentation
Identified Issues (per cited reviewer):
- USB-C cable compatibility problems for firmware updates
- Complex Wi-Fi setup process
- Documentation clarity issues
- Potential firmware compatibility limitations between versions
- Antenna optimization still in development
Video – ATS Mini ESP32 receiving Shortwave radio
Based on available user feedback with proper attribution, the ATS MINI ESP32-S3 SI4732 shows promise as an evolving platform with active development. The most detailed user review indicates improving build quality and innovative features like EiBi integration, but also reveals practical challenges with setup complexity and documentation clarity.
The limited number of detailed, attributed reviews suggests either restricted market penetration or the product’s relatively recent introduction to the market. Potential buyers should consider this limited review base when making purchasing decisions, particularly given the documented variations in quality and firmware compatibility between versions.
The ATS MINI ESP32-S3 SI4732 Pocket Radio DSP Receiver represents a significant achievement in portable radio technology, combining the power of modern microcontrollers with advanced digital signal processing to create a versatile, capable, and user-friendly device. Its open-source foundation ensures continued development and customization possibilities, while its compact form factor and comprehensive feature set make it suitable for a wide range of applications from amateur radio to professional monitoring.
The integration of the ESP32-S3 and SI4732 creates a platform that not only provides excellent radio reception capabilities but also serves as a foundation for future innovations in portable radio technology. Whether used for emergency preparedness, hobbyist exploration, or professional applications, the ATS MINI demonstrates the potential of combining traditional radio engineering with modern digital technology to create solutions that are both powerful and accessible to the broader community.
ATS Mini – Important Links
| Latest Firmware | Download firmware (default) | Download firmware(V1.01) | Flash tool download zip file (win10) |
About The Author