Iwatake’s project uses a Raspberry Pi Pico to display a live audio spectrum, with the RP2040’s two cores sharing the work: one handles audio input, buffering and the display, while the other calculates the FFT. The project is described as a C++ build using the official Pico SDK, but its account also reports intermittent freezes and does not specify key performance settings such as sample rate or FFT length.
How the Pico spectrum analyzer works
The Raspberry Pi Pico is the central board. Its RP2040 microcontroller has two cores, which Iwatake’s project description uses to divide the analyzer’s work. Audio enters through the Pico’s ADC, and a touch-sensitive display connected over SPI shows the live spectrum.
Work split between the cores
One core runs the main thread, reads ADC input, stores samples in buffers and handles the SPI display. The other core calculates the FFT used to produce the spectrum display. This division describes the project’s design; no measured speedup or latency is reported.
Software and interfaces
The project is written in C++ with the official Raspberry Pi Pico SDK. Its description names ADC, DMA, IRQ and SPI, but does not identify the microphone or display model. The available account also does not provide a complete parts list, so those component choices cannot be inferred from the project description.
#1 Best Overall
- RP2040 microcontroller chip designed by Raspberry Pi in the United Kingdom
- Dual-core Arm Cortex M0+ processor, flexible clock running up to 133 MHz
- 264KB of SRAM, and 2MB of on-board Flash memory
- Castellated module allows soldering direct to carrier boards
- 26 × multi-function GPIO pins
What is—and is not—known about its performance
The project coverage does not state the FFT length, audio sample rate, display refresh rate, latency, benchmark results or tested throughput. As a result, the term “live” describes the intended display behavior, not a quantified real-time performance guarantee.
For context only, V. Hunter Adams documents a separate RP2040 FFT implementation that paces ADC sampling at 10 kHz, collects 1,024 samples with DMA, and computes and displays a batch while the next is captured. Those figures describe Adams’s project, not Iwatake’s, and should not be used as settings or performance claims for this analyzer. See Adams’s RP2040 FFT example for that separate workflow.
Rank #2
- The Raspberry Pi Pico is a beginner-friendly microcontroller board that uses MicroPython to give you a taste of the Internet of Things and microcontrollers. The RP2040 is a well-designed microprocessor that can be utilized in almost any Internet of Things project. It has enough power to complete the task quickly.
- 【Raspberry Pi RP2040 Microcontroller】Raspberry Pi Pico features Dual-core ARM Cortex M0+ processor, flexible clock running up to 133 MHz. With 264KB of SRAM, and 2MB of on-board Flash memory.Supports up to 16 MB of off chip flash memory via a dedicated QSPI bus
- 【Multiple Software Support】Pico has rich and complete software support, it comes with a complete Rasberry Pi official C/C++ SDK, Micropython SDK.The programming and burning of Pico need to be carried out on the computer. Supported operating systems and computers include:Raspberry Pie with Raspberry Pi OS,Other platforms equipped with Debian based Linux system Computer with MacOS, Computers with Windows, etc.
- 【Rich Hardware Interface】Raspberry Pi Pico has 30 GPIO pins, 4 pins for analog signal input and 26 × multi-function GPIO pins, 2 × SPI, 2 × I2C, 2 × UART, 3 × 12-bit ADC, 16 × controllable PWM channels.USB 1.1 supported by host and device, The installation mode can be flexibly selected by users to facilitate welding with other development boards.
- 【Build Project in Tiny Size】Only 2.1cm*5.1cm ( as small as your thumb). Pico has been designed to use either soldered 0.1" pin-headers or can be used as a surface-mountable 'module'.
Reliability caveat: freezes were reported
Hackster’s account attributes a warning to Iwatake: “There seems to be a bug,” and the system “often freeze!” The cause was described as unknown. This is a reported issue, not an independently reproduced defect, and the account does not establish that it was later fixed. The project therefore should not be described as reliably stable on the available evidence.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What you need to reproduce the build
The named core component is a Raspberry Pi Pico, alongside an analog audio input and a touch-sensitive SPI display. Because the project account does not identify exact microphone or display models or supply a complete bill of materials, verify compatible components and wiring against the project repository before buying parts. The account’s C++ and official Pico SDK description offers a starting point for the software side, but does not specify build steps or configuration values.
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Best Value
- Raspberry Pi Pico: A tiny, fast, and versatile board built using dual-core Arm Cortex-M0+ processor (Comes with pinout card and stickers)
- Detailed Tutorial: Provides step-by-step guide with MicroPython, C and Processing (Java) Code (The download link can be found on the product box) (No paper tutorial)
- Example Projects: Each project has schematics, wiring diagrams, complete code and detailed explanations (Need extra items)
- Easy to Use: Just connect the board to your computer (installed IDE) with the USB cable to program it
- Get Support: Our technical support team is always ready to answer your questions
Rank #4
- New Flexible Microcontroller Board --- Raspberry Pi Pico is a tiny, fast, and versatile board. It's based on RP2040 chip, which features a dual-core Arm Cortex-M0+ processor with 264KB internal RAM and support for up to 16MB of off-chip Flash, flexible clock running up to 133 MHz.
- Multi-Function GPIO Pins---It has 26 multifunction GPIO pins, including 3 analogue inputs, 2 × UART, 2 × SPI controllers, 2 × I2C controllers, 16 × PWM channels.
- Rich Peripheral Set---A wide range of flexible I/O options includes I2C, SPI, and — uniquely —8 × Programmable I/O (PIO) state machines for custom peripheral support.
- Multiple Software Support---Raspberry Pi Pico has rich and complete software support and community resources. Programmable in C and MicroPython. Drag-and-drop programming using mass storage over USB.
- Low-power sleep and dormant modes; Accurate on-chip clock; Temperature sensor; Accelerated integer and floating-point libraries on-chip
Rank #3
- with pre-soldered header Raspberry Pi Pico. RP2040 microcontroller chip designed by Raspberry Pi in the United Kingdom
- Dual-core Arm Cortex M0+ processor, flexible clock running up to 133 MHz. 264KB of SRAM, and 2MB of on-board Flash memory.
- Castellated module allows soldering direct to carrier boards. USB 1.1 with device and host support. Low-power sleep and dormant modes. Drag-and-drop programming using mass storage over USB. 26 × multi-function GPIO pins.
- 2 × SPI, 2 × I2C, 2 × UART, 3 × 12-bit ADC, 16 × controllable PWM channels.Accurate clock and timer on-chip.Temperature sensor.
- Accelerated floating-point libraries on-chip.8 × Programmable I/O (PIO) state machines for custom peripheral support
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