PÚCA DSP is an open-source, Arduino-compatible ESP32 development board for audio and digital signal processing (DSP) applications with expansive audio-processing features. It provides audio inputs, audio outputs, a low-noise microphone array, an integrated test-speaker option, additional memory, battery-charge management, and ESD protection all on a small, breadboard-friendly PCB.
Synthesizers, Installations, Voice UI, and More
PÚCA DSP can be used for a wide range of DSP applications, including but not limited to those in the fields of music, art, creative technology, and adaptive technology. Music-related examples include digital-music synthesis, mobile recording, Bluetooth speakers, wireless line-level directional microphones, and the design of smart musical instruments. Art-related examples include acoustic sensor networks, sound-art installations, and Internet-radio applications. Examples related to creative and adaptive technology include voice user interface (VUI) design and Web audio for the Internet of Sounds.
Compact, Integrated Design
PÚCA DSP was designed for portability. When used with an external 3.7 V rechargeable battery, it can be deployed almost anywhere or integrated into just about any device, instrument, or installation. Its design emerged from months of experimentation with various ESP32 development boards, DAC breakout boards, ADC breakout boards, Microphone breakout boards, and audio-connector breakout boards, and – despite its diminutive size – it manages to provide all of that functionality in a single board. And it dos so without compromising signal quality.
Specifications
Processor & Memory
Espressif ESP32 Pico D4 Processor
32-bit dual core 80 MHz / 160 MHz / 240 MHz
4 MB SPI Flash with 8 MB additional PSRAM (Original Edition)
Wireless 2.4 GHz Wi-Fi 802.11b/g/n
Bluetooth BLE 4.2
3D Antenna
Audio
Wolfson WM8978 Stereo Audio Codec
Audio Line In on 3.5 mm stereo onnector
Audio Headphone / Line Out on 3.5 mm stereo connector
Stereo Aux Line In, Audio Mono Out routed to GPIO Header
2x Knowles SPM0687LR5H-1 MEMS Microphones
ESD protection on all audio inputs and outputs
Support for 8, 11.025, 12, 16, 22.05, 24, 32, 44.1 and 48 kHz sample rates
1 W Speaker Driver, routed to GPIO Header
DAC SNR 98 dB, THD -84 dB (‘A’ weighted @ 48 kHz)
ADC SNR 95 dB, THD -84 dB (‘A’ weighted @ 48 kHz)
Line input impedance: 1 MOhm
Line output impedance: 33 Ohm
Form Factor and Connectivity
Breadboard friendly
70 x 24 mm
11x GPIO pins broken out to 2.54 mm pitch header, with access to both ESP32 ADC channels, JTAG and capacitive touch pins
USB 2.0 over USB Type C connector
Power
3.7/4.2 V Lithium Polymer Rechargeable Battery, USB or external 5 V DC power source
ESP32 and Audio Codec can be placed into low power modes under software control
Battery voltage level detection
ESD protection on USB data bus
Downloads
GitHub
Datasheet
Links
Crowd Supply Campaign (includes FAQs)
Hardware Overview
Programming the Board
The Audio Codec
Easy and Affordable Digital Signal Processing
The aim of this book is to teach the basic principles of Digital Signal Processing (DSP) and to introduce it from a practical point of view using the bare minimum of mathematics. Only the basic level of discrete-time systems theory is given, sufficient to implement DSP applications in real time. The practical implementations are described in real time using the highly popular ESP32 DevKitC microcontroller development board. With the low cost and extremely popular ESP32 microcontroller, you should be able to design elementary DSP projects with sampling frequencies within the audio range. All programming is done using the popular Arduino IDE in conjunction with the C language compiler.
After laying a solid foundation of DSP theory and pertinent discussions on the main DSP software tools on the market, the book presents the following audio-based sound and DSP projects:
Using an I²S-based digital microphone to capture audio sound
Using an I²S-based class-D audio amplifier and speaker
Playing MP3 music stored on an SD card through an I²S-based amplifier and speaker
Playing MP3 music files stored in ESP32 flash memory through an I²S-based amplifier and speaker
Mono and stereo Internet radio with I²S-based amplifiers and speakers
Text-to-speech output with an I²S-based amplifier and speaker
Using the volume control in I²S-based amplifier and speaker systems
A speaking event counter with an I²S-based amplifier and speaker
An adjustable sinewave generator with I²S-based amplifier and speaker
Using the Pmod I²S2 24-bit fast ADC/DAC module
Digital low-pass and band-pass real-time FIR filter design with external and internal A/D and D/A conversion
Digital low-pass and band-pass real-time IIR filter design with external and internal A/D and D/A conversion
Fast Fourier Transforms (FFT)
This DIY kit (HU-017A) is a wireless FM radio receiver with a 4-digit 7-segment display. It operates within the global FM receiving frequency band of 87.0-108.0 MHz, making it suitable for use in any country or region. The kit offers two power supply modes, allowing you to use it both at home and outdoors. This DIY electronic product will help you understand circuits and improve your soldering skills.
Features
87.0-108.0 MHz FM Radio: Built-in RDA5807 FM data processor with a standard FM receiving frequency band. The FM frequency can be adjusted using the F+ and F- buttons.
Adjustable Volume: Two volume adjustment methods – button and potentiometer. There are 15 volume levels.
Active & Passive Audio Output: The kit has a built-in 0.5 W power amplifier to drive 8 Ω speakers directly. It also outputs audio signals to headsets or loudspeakers with AUX interfaces, allowing personal listening and sharing of FM audio.
Configured with a 25 cm dedicated FM antenna and a (red) 4-digit 7-segment display for real-time display of FM radio frequency. The transparent acrylic shell protects the internal circuit board. It supports dual power supply methods – 5 V USB and 2x 1.5 V (AA) batteries.
DIY Hand Soldering: The kit comes with various components that need to be installed manually. It helps exercise and improve soldering skills, making it suitable for electronics hobbyists, beginners, and educational purposes.
Specifications
Operating voltage
DC 3 V/5 V
Output impedance
8 Ω
Output power
0.5 W
Output channel
Mono
Receiver frequency
87.0 MHz~108.0 MHz
Frequency accuracy
0.1 MHz
Operating temperature
−40°C to +85°C
Operating humidity
5% to 95% RH
Dimensions
107 x 70 x 23 mm
IMPORTANT: Remove the batteries when powering the radio over to USB.
Included
1x PCB
1x RDA5807M FM Receiver
1x STC15W404AS MCU
1x IC Socket
1x 74HC595D Register
1x TDA2822M Amplifier
1x IC Socket
1x AMS1117-3.3 V Voltage Converter
18x Metal Film Resistor
1x Potentiometer
4x Ceramic Capacitor
5x Electrolytic Capacitor
4x S8550 Transistor
1x Red LED
1x 4-digit 7-segment Display
1x Toggle Switch
1x SMD Micro USB Socket
1x Radio Antenna
1x AUX Audio Socket
4x Black Button
4x Button Cap
1x 0.5 W/8 Ω Speaker
1x Red/Black Wire
2x Double-sided adhesive
1x AA Battery Box
1x USB cable
6x Acrylic Board
4x Nylon Column Screw
4x M3 Screw
4x M3 Nut
4x M2x22 mm Screw
1x M2x6 mm Screw
5x M2 Nut
The Elektor Audio DSP FX Processor combines an ESP32 microcontroller and an ADAU1701 Audio DSP from Analog Devices. Besides a user-programmable DSP core, the ADAU1701 has high-quality analog-to-digital and digital-to-analog converters built-in and features an I²S port. This makes it suitable as a high-quality audio interface for the ESP32.
Programs for the ESP32 can be created with Arduino, Platform IO, CMake or by using the Espressif IDF in another way. Programs for the ADAU7101 audio DSPs are created with the free visual programming tool SigmaStudio by dragging and dropping pre-defined algorithm blocks on a canvas.
Applications
Bluetooth/Wi-Fi audio sink (e.g. loudspeaker) & source
Guitar effect pedal (stomp box)
Music synthesizer
Sound/function generator
Programmable cross-over filter for loudspeakers
Advanced audio effects processor (reverb, chorus, pitch shifting, etc.)
Internet-connected audio device
DSP experimentation platform
Wireless MIDI
MIDI to CV converter
and many more...
Specifications
ADAU1701 28-/56-bit, 50-MIPS digital audio processor supporting sampling rates of up to 192 kHz
ESP32 32-bit dual-core microcontroller with Wi-Fi 802.11b/g/n and Bluetooth 4.2 BR/EDR and BLE
2x 24-bit audio inputs (2 V RMS, 20 kΩ)
4x 24-bit audio outputs (0.9 V RMS, 600 Ω)
4x Control potentiometer
MIDI in- and output
I²C expansion port
Multi-mode operation
Power supply: 5 V DC USB or 7.5-12 V DC (barrel jack, center pin is GND)
Current consumption (average): 200 mA
Included
1x ESP32 Audio DSP FX Processor board (assembled)
1x ESP32-PICO-KIT
2x Jumpers
2x 18-pin headers (female)
4x 10 KB potentiometers
Downloads
Documentation
GitHub
Easy and Affordable Digital Signal ProcessingThe aim of this book is to teach the basic principles of Digital Signal Processing (DSP) and to introduce it from a practical point of view using the bare minimum of mathematics. Only the basic level of discrete-time systems theory is given, sufficient to implement DSP applications in real time. The practical implementations are described in real time using the highly popular ESP32 DevKitC microcontroller development board. With the low cost and extremely popular ESP32 microcontroller, you should be able to design elementary DSP projects with sampling frequencies within the audio range. All programming is done using the popular Arduino IDE in conjunction with the C language compiler.After laying a solid foundation of DSP theory and pertinent discussions on the main DSP software tools on the market, the book presents the following audio-based sound and DSP projects:
Using an I²S-based digital microphone to capture audio sound
Using an I²S-based class-D audio amplifier and speaker
Playing MP3 music stored on an SD card through an I²S-based amplifier and speaker
Playing MP3 music files stored in ESP32 flash memory through an I²S-based amplifier and speaker
Mono and stereo Internet radio with I²S-based amplifiers and speakers
Text-to-speech output with an I²S-based amplifier and speaker
Using the volume control in I²S-based amplifier and speaker systems
A speaking event counter with an I²S-based amplifier and speaker
An adjustable sinewave generator with I²S-based amplifier and speaker
Using the Pmod I²S2 24-bit fast ADC/DAC module
Digital low-pass and band-pass real-time FIR filter design with external and internal A/D and D/A conversion
Digital low-pass and band-pass real-time IIR filter design with external and internal A/D and D/A conversion
Fast Fourier Transforms (FFT)
The nRSP-ST is a networked general coverage radio receiver for frequencies from 1 kHz to 2 GHz with up to 10 MHz of spectrum visibility. The nRSP-ST is your own personal remotely accessible SDR which can also be shared with a small number of trusted friends or colleagues.
The nRSP-ST addresses the needs of radio enthusiasts who want a 'plug-and-play' solution for remote reception. As well as achieving this, we have addressed typical internet bandwidth limitations with the creation of a novel IQ Lite mode, which efficiently delivers channels of IQ data. We are also introducing the ability to control and store IQ recordings at the remote location. The nRSP-ST is ideal for anyone wanting a wideband remote receiver without needing computer skills and hours of set-up time and ongoing maintenance at the remote location.
Features
"Plug and play" integrated, networked general coverage receiver:
Combines a receiver, a host computer and a whole lot more – all in one box!
Apply power and connect to the internet (Ethernet or Wi-Fi) and the nRSP-ST is automatically accessible from anywhere
Multi-platform SDRconnectTM software supports local operation or remote access on Windows, MacOS or Linux platforms
The nRSP-ST & SDRconnect are configurable for available network bandwidth:
In Full IQ mode, the nRSP-ST provides IQ data transfer of the visible spectrum bandwidth (e.g. for high-speed LAN or superfast internet connectivity)
In IQ Lite mode, the nRSP-ST provides IQ data of channels up to 192 kHz wide (e.g. for digital decoding by the client)
In Compact mode the nRSP-ST provides compressed audio (ideal for slower internet connections)
Supports multiple client connections with a simultaneous mixture of connection modes – an admin tool allows you to assign usernames and timeouts to trusted friends or colleagues.
All modes support visualization of up to 10 MHz spectrum bandwidth
Two remote connection options:
Use a remote SDRconnect client or
Use the built-in web-server for remote access from any web browsing capable device, including Android/iOS tablets and phones
The nRSP-ST offers the ability to record IQ and audio files to a NAS (network attached storage) device if available on the LAN.
The 14-bit ADC full featured wideband SDR receiver covers all frequencies from 1 kHz through VLF, LF, MW, HF, VHF, UHF and L-band to 2 GHz, with no gaps
Remotely monitor up to 10 MHz of spectrum at a time from a choice of 3 antennas
Flash upgradable for future feature enhancements
Included
1x nRSP-ST Receiver
1x WLAN antenna
1x Power supply
1x Manual
Downloads
Release notes
Software
The SDRplay RSP1B is an enhanced version of the popular RSP1A – a powerful, wideband, full-featured 14-bit SDR that covers the RF spectrum from 1 kHz to 2 GHz. The RSP1B comes in a rugged, black-painted steel case and offers significantly improved noise performance.
All it needs is a computer and an antenna to deliver excellent communications-receiver functionality. It includes a choice of SDRuno for Windows and the multi-platform SDRconnect software for Windows, macOS, and Linux (supplied free of charge by SDRplay). You can monitor up to 10 MHz of spectrum at a time.
A documented API allows developers to create new demodulators or applications for the platform.
Features
Covers all frequencies from 1 kHz through VLF, LF, MW, HF, VHF, UHF and L-band to 2 GHz, with no gaps
Receive, monitor and record up to 10 MHz of spectrum at a time
Free use of windows-based SDRuno software which provides an ever-increasing feature-set
Strong and growing software support network
Calibrated S meter/ RF power and SNR measurement with SDRuno (including datalogging to .CSV file capability)
Documented API provided to allow demodulator or application development on multiple platforms
Excellent dynamic range for challenging reception conditions
Works with popular 3rd party SDR software (including HDSDR, SDR Console and Cubic SDR)
ExtIO based plugin available
Software upgradeable for future standards
Strong and growing software support network
API provided to allow demodulator or application development
Multiplatform driver and API support including Windows, Linux, Mac, Android and Raspberry Pi
Up to 16 individual receivers in any 10 MHz slice of spectrum using SDRuno
Calibrated S meter and power measurements with SDRuno
Stand-alone windows-based spectrum analyser software available (with sweep, sample and hold features)
Ideal for monitoring of ISM/ IoT/ Telemetry bands <2 GHz
Ideal for portable operation
Specifications
Frequency Range
1 kHz – 2 GHz
Antenna Connector
SMA
Antenna Impedance
50 Ohms
Current Consumption (Typical)
185 mA (excl. Bias-T)
USB Connector
USB Type B
Maximum Input Power
+0 dBm Continuous+10 dBm Short Duration
ADC Sample Rates
2-10.66 MSPS
ADC Number of Bits
14 bit 2-6.048 MSPS12 bit 6.048-8.064 MSPS10 bit 8.064-9.216 MSPS8 bit >9.216 MSPS
Bias-T
4.7 V100 mA guaranteed
Reference
0.5ppm 24 MHz TCXO.Frequency error trimmable to 0.01ppm in field.
Operating Temperature Range
-10˚C to +60˚C
Dimensions
98 x 88 x 34 mm
Weight
110 g
Downloads
Datasheet
Software
RSP1B vs RSPdx vs RSPduo
RSP1B
RSPdx
RSPduo
Continuous coverage from 1 kHz to 2 GHz
✓
✓
✓
Up to 10 Mhz visible bandwidth
✓
✓
✓
14-bit ADC silicon technology plus multiple high-performance input filters
✓
✓
✓
Software selectable AM/FM & DAB broadcast band notch filters
✓
✓
✓
4.7 V Bias-T for powering external remote antenna amplifier
✓
✓
✓
Powers over the USB cable with a simple type B socket
✓
✓
✓
50Ω SMA antenna input(s) for 1 kHz to 2 GHz operation (software selectable)
1
2
2
Additional software selectable Hi-Z input for up to 30 Mhz operation
✓
Additional software selectable 50Ω BNC input for up to 200 MHz operation
✓
Additional LF/VLF filter for below 500 kHz
✓
24 MHz reference clock input (+ output on RSPduo)
✓
✓
Dual tuners enabling reception on 2 totally independent 2 MHz ranges
✓
Dual tuners enabling diversity reception using SDRuno
✓
Robust and strong plastic case (with internal RF shielding layer)
✓
Rugged black painted steel case
✓
✓
Overall performance below 2 MHz for MW and LF
+
++
+
Multiple simultaneous applications
+
+
++
Performance in challenging fading conditions (*using diversity tuning)
+
+
*++
A comprehensive course that will teach you how to build a modern IoT application This book will take you on a whirlwind tour of full-stack web application development using Raspberry Pi. You will learn how to build an application from the ground up. You will gain experience and know-how of technologies including: The Linux operating system and command line. The Python programming language. The Raspberry Pi General Purpose Input Output pins (GPIOs). The Nginx web server. Flask Python web application microframework. JQuery and CSS for creating user interfaces. Dealing with time zones. Creating charts with Plotly and Google Charts. Data logging with Google Sheet. Developing applets with IFTTT. Securing your application with SSL. Receiving SMS notifications to your phone using Twilio. This book will also teach you how to set up a remote wireless Arduino sensor node and collect data from it. Your Raspberry Pi web application will be able to process Arduino node data in the same way it processes data from its onboard sensor. Raspberry Pi Full Stack will teach you many skills essential to building Web and Internet of Things applications. The application you will build in this project is a platform that you can extend upon. This is just the start of what you can do with a Raspberry Pi and the software and hardware components that you will learn about. This book is supported by the author via a dedicated discussion space.
The SDRplay RSPduo is a high performance dual-tuner 14-bit SDR receiver. Housed in a high quality steel enclosure, each tuner can operate individually anywhere between 1 kHz and 2 GHz with up to 10 MHz of bandwidth or both tuners can operate simultaneously anywhere between 1 kHz and 2 GHz with up to 2 MHz of bandwidth per tuner.
A high stability reference along with external clocking features makes this device ideally suited to industrial, scientific & educational applications.
Features
Dual tuner provides independent coverage from 1 kHz to 2 GHz using 2 antenna ports simultaneously
14-bit ADC silicon technology
Up to 10 MHz visible bandwidth (single tuner mode) or 2 slices of 2 MHz spectrum (dual tuner mode)
3 software-selectable antenna ports (2x 50Ω and 1x 1kΩ high impedance balanced/unbalanced input)
High impedance antenna port (1 kHz to 30 MHz) with selectable MW notch filter and choice of 2 pre-selection filters
Software selectable AM/FM and DAB broadcast band notch filters for the 2 SMA antenna (1 kHz to 2 GHz) antenna ports
External clock input and output enables easy synchronisation to multiple RSPs or external reference clock
Powers over the USB cable with a simple type B socket
11 high-selectivity, built in front-end preselection filters on both the 2 SMA antenna ports
Software selectable multi-level Low Noise Preamplifier
Bias-T power supply for powering antenna-mounted LNA
Enclosed in a rugged black painted steel case.
SDRuno – World Class SDR software for Windows
Documented API for new apps development
Specifications
Frequency Range
1 kHz – 2 GHz
Antenna Connector
SMA
Antenna Impedance
50 Ohms
Current Consumption (Typical)
Single Tuner Mode: 180 mA (excl. Bias-T)Dual Tuner Mode: 280 mA (excl. Bias-T)
USB Connector
USB-B
Maximum Input Power
+0 dBm Continuous+10 dBm Short Duration
ADC Sample Rates
2-10.66 MSPS
ADC Number of Bits
14 bit 2-6.048 MSPS12 bit 6.048-8.064 MSPS10 bit 8.064-9.216 MSPS8 bit >9.216 MSPS
Bias-T
4.7 V100 mA guaranteed
Reference
High Temperature Stability (0.5ppm) 24 MHz TCXO.Frequency error trimmable to 0.01ppm in field.
Operating Temperature Range
−10˚C to +60˚C
Dimensions
98 x 94 x 33 mm
Weight
315 g
Downloads
Datasheet
Detailed Technical Information
Software
RSPdx-R2 vs RSPduo
RSPdx-R2
RSPduo
Continuous coverage from 1 kHz to 2 GHz
✓
✓
Up to 10 MHz visible bandwidth
✓
✓
14-bit ADC silicon technology plus multiple high-performance input filters
✓
✓
Software selectable AM/FM & DAB broadcast band notch filters
✓
✓
4.7 V Bias-T for powering external remote antenna amplifier
✓
✓
Powers over the USB cable with a simple type B socket
✓
✓
50Ω SMA antenna input(s) for 1 kHz to 2 GHz operation (software selectable)
2
2
Additional software selectable Hi-Z input for up to 30 Mhz operation
✓
Additional software selectable 50Ω BNC input for up to 200 MHz operation
✓
Additional LF/VLF filter for below 500 kHz
✓
24 MHz reference clock input (+ output on RSPduo)
✓
✓
Dual tuners enabling reception on 2 totally independent 2 MHz ranges
✓
Dual tuners enabling diversity reception using SDRuno
✓
Rugged black painted steel case
✓
✓
Overall performance below 2 MHz for MW and LF
++
+
Multiple simultaneous applications
+
++
Performance in challenging fading conditions (*using diversity tuning)
+
*++
,
by Sebastian Westerhold
The SDRplay RSPdx SDR Receiver Features Frequency Range of 1 kHz up to 2 GHz (Review)
The SDRplay RSPdx is a 14-bit single-tuner receiver with continuous coverage from 1 kHz up to 2GHz. Three input connectors, an ample array of software...