If you're thinking about it AMYboard ESP32-S3 synthesizer board with MIDI and CV And if you're wondering whether it really fits your project, you're not alone. Many makers find themselves in the same situation: they've seen a dev board with an ESP32-S3-WROOM chip, compared it to other boards with integrated screens, batteries, and sensors, and are unsure if it's the best option for building a modern and versatile MIDI controller.
The idea is clear: you want MIDI via USB, possibly MIDI BLE, Hall effect sensor reading and mechanical keyboard pushbuttons Through 8:1 multiplexers, it also leaves the door open for a small screen and a battery to create a portable and wireless device. Let's break down what a board based on the ESP32-S3 can offer, what alternatives exist with circular LCD or AMOLED screens, and whether you're really on the right track... or if there's something you should reconsider before you continue soldering.
What does an AMYboard ESP32-S3 board really offer for MIDI and CV?
The base of this plate is a ESP32-S3-WROOM moduleThe ESP32-S3 is a highly capable SoC for digital audio projects, MIDI controllers, and interactive systems. It features a dual-core processor, 2,4 GHz Wi-Fi connectivity, Bluetooth Low Energy (BLE), and a host of peripherals for handling digital and analog inputs, communication buses, and more. The AMYboard, or any well-designed ESP32-S3 development board, is built upon this chip to provide a set of pins, connectors, and sometimes additional peripherals.
In the context of a synthesizer with MIDI and CVWhat matters most is having enough GPIO pins, good native USB support for MIDI, the option to work with BLE in the future, and an architecture that won't fall short when you start adding features (displays, batteries, additional sensors, etc.). The ESP32-S3 meets these requirements and has become a de facto standard for DIY projects that combine audio, control, and wireless connectivity.
Furthermore, this type of motherboard usually offers a good price/performance ratio, which is key if you want to experiment with Hall effect sensors, HE mechanical keyboard switches and multiplexers without skyrocketing hardware costs. You're not buying a basic prototyping board: it's a powerful enough platform to build a serious MIDI controller and expand it over time.
On the other hand, many variants of ESP32-S3 boards, including those used as a basis for AMYboard or similar projects, have been designed with the developer in mind: logical pin arrangement, easy access to power, well-integrated USB ports and, in some cases, extras such as connectors for batteries or displays.
MIDI over USB on ESP32-S3: feasibility and real limitations
One of the points that generates the most doubt is whether MIDI over USB works well on an ESP32-S3 boardThe fear of having made a "big mistake" often comes from confusing boards with USB only for power with boards that expose the microcontroller's native USB for functions such as MIDI, HID, etc.
The ESP32-S3 incorporates USB OTG nativelyThis means that, with the appropriate firmware, it can behave as a USB-MIDI device. You're not limited to a USB-UART bridge chip; you can make the microcontroller recognize itself to the computer directly as a MIDI interface. Libraries and frameworks like ESP-IDF and certain community projects have already demonstrated that this is possible and operational in real-world contexts.
In practice, for your controller with Hall effect sensors and mechanical keys, you will be able to generate MIDI messages Note On/Off, Control Change or other MIDI messages and send them to the computer or another USB host. The key point is to ensure that the specific development board you use correctly exposes the ESP32-S3's native USB port, not just a serial converter.
If the AMYboard ESP32-S3 or a similar board you have in mind uses the ESP32-S3-WROOM with USB OTG access, you have the core requirement of your project covered: Fully functional USB MIDIThere is nothing inherent in this chip that prevents the implementation of USB-MIDI; on the contrary, it is one of the advantages over previous generations.
Therefore, far from having "messed up" your choice, you're most likely using a platform suitable for your idea. The work will lie in the firmware and how you structure the code to manage both sensor readings and MIDI communication without introducing excessive latency.
Reading Hall effect sensors, HE switches and 8:1 multiplexers
Your scenario starts from an input matrix based on Hall effect sensors and Hall-Effect (HE) switches of mechanical keyboardconnected to two 8:1 multiplexers for velocity detection. This approach is very interesting for building velocity-sensitive keyboards without relying on traditional rubber contacts or dual-switch mechanisms.
The ESP32-S3 + multiplexer combination is entirely feasible. With just two 8:1 multiplexers, you can read a reasonable number of sensors, provided you manage the selection lines and sampling correctly. The microcontroller has Sufficient GPIO pins to handle the multiplexer control lines and receive the output signals, without forgetting that you will also have to reserve pins for other peripherals.
If you plan the pin assignments thoughtfully, you can connect the multiplexers so that the ESP32-S3 quickly and cyclically reads the state of each Hall sensor. From this data, the pulse rate can be calculated. temporal variation of the signal between two thresholds, something that the dual-core processor handles without problems within a well-structured application.
Mechanical keyboards with Hall-effect technology or dedicated sensors allow for very precise control of the actuation point and can send rich information to the microcontroller. The ESP32-S3 is certainly not lacking in power to manage this. periodic multiplexer readings, basic signal filtering, and MIDI message sending practically in real time, as long as you take care of the code's efficiency.
Furthermore, having a modern SoC facilitates the later integration of more advanced features, such as configurable velocity curves, key layers, alternative performance modes, or combination with CV outputs to control analog synthesizers.
MIDI BLE capabilities with ESP32-S3
Another of your wishes is to add more later MIDI BLE (Bluetooth Low Energy) Once you're more confident with wireless communication, the ESP32-S3 comes to your advantage again, as it integrates BLE as standard and allows you to implement custom profiles on GATT.
The MIDI BLE standard defines how to encapsulate traditional MIDI messages over a BLE connection geared towards low latencyOn the ESP32-S3 you can set up a BLE service that exposes the necessary features to send and receive MIDI data wirelessly, using libraries available in the community or starting from official BLE examples and adapting them to the MIDI protocol.
The key point is not so much whether it's possible or not, which it is, but how to manage it. latency, connection stability, and energy consumptionEspecially if you later want to add a battery to make the device truly wireless. But the motherboard and chip provide the technical foundation to do so, so you're not choosing a processor that will limit you in this regard.
From a firmware design perspective, an architecture where the ESP32-S3 sends MIDI over USB when connected to a host and, alternatively or simultaneously, exposes a MIDI BLE service is entirely viable. The challenge is to properly coordinate the message queues to avoid data loss and keep everything synchronized.
In summary, at the level of MIDI connectivity via both USB and BLEA project based on the AMYboard ESP32-S3 has room to grow and cover quite ambitious use cases, from a simple wired-controlled keyboard to a completely wireless controller.
Displays: I2C, 1.7″ touch LCD and 1.75″ circular AMOLED
One of the extras you might like to add, although it's not essential from the start, is a small screen for user interfaceThe idea of ​​using I2C is logical: 8-bit parallel displays consume many pins, and you're prioritizing sensor inputs and connection flexibility.
I2C displays, such as classic OLEDs or small LCDs based on standard drivers, are ideal for Display basic synthesizer parameters, presets, configuration menus, and visual feedbackThe I2C bus only requires two lines (SDA and SCL), leaving most of the pins free for your sensor array and other functions.
However, there are also ESP32-S3 development boards that already include more advanced integrated displaysAnd this is where alternatives you've seen on websites that rank well for this type of search come in. For example, ESP32-S3 boards are sold with:
- 1.7-inch touch LCD screen, 240 x 280 pixel resolution and 262K colors, which turns the board into a kind of mini visual control panel.
- 1.75-inch circular AMOLED display, also with touchscreen, dual microphone array and 6-axis IMUdesigned for more eye-catching interfaces and portable devices with touch interaction.
These ESP32-S3 board variants with integrated displays greatly simplify the hardware: you don't have to wire external displays or worry about the interface type, as the screen comes soldered and tested. Furthermore, the resolution and color allow for the creation of rich graphical interfaces, with VU meters, menus, synthesis parameter indicators, and CV control, all embedded in the circuit board itself.
The downside is that, by integrating touchscreens and other sensors (accelerometers, gyroscopes, microphone arrays, etc.), these boards tend to consume more resources and have a more complex pin layout. If your absolute priority is the GPIO pins for multiplexers, CV outputs and external hardware controlYou might prefer an I/O-focused AMYboard to a super-integrated board with a circular display.
In any case, the ESP32-S3 easily supports both simple I2C displays and LCD or AMOLED displays controlled by high-speed buses (SPI, for example). Your decision hinges more on finding the right balance between hardware complexity, cost, and number of available pins due to the microcontroller's capabilities.
Battery and fully wireless use
Another of your aspirations is to set up a integrated battery that allows you to use the synthesizer or MIDI controller wirelesslyHere it is worth looking at the ESP32-S3 development boards that are already being sold with a battery included or, at least, with an integrated charging circuit.
In the list of products similar to the one you are looking at, there is one ESP32-S3 development board with 1.75-inch circular AMOLED touchscreen, dual microphone array, 6-axis IMU, 2.4 GHz Wi-Fi, and, very importantly, a built-in batteryThis type of board is specifically designed to function as a portable device: you can charge the battery via USB and use the system without being tethered to the cable.
If your AMYboard ESP32-S3 doesn't come with a battery, you can always add one. external power module with LiPo charger and protection circuitby connecting it to the board's power input. The ESP32-S3 works well with this type of solution, provided the module's output voltage matches the board's specifications (usually 5V via USB or 3,3V regulated on the circuit itself).
The advantage of using a board with an integrated battery is simplicity: fewer external modules, less soldering, and fewer potential errors in the power supply design. Combine this with MIDI BLE, and you have a... truly wireless synthesizer controller, capable of sending notes and controls via Bluetooth without relying on physical cables.
The downside is that, again, some of these all-in-one boards sacrifice some pin layout flexibility and can be somewhat more expensive than an AMYboard focused on GPIO and basic connectivity. You'll have to decide whether optimizing I/O or portability and a more polished product finish is more important for your workflow.
Comparison with other ESP32-S3 boards with screen and sensors
In the ecosystem of ESP32-S3 boards mentioned on top-ranked websites, there are several relevant options worth considering alongside the AMYboard. They all share the same base as ESP32-S3 microcontrollerHowever, they differ in integrated peripherals and intended use.
On the one hand, there is the Integrated development board with 1.7-inch touch LCD screen, 240 x 280 pixels and 262K colorsThis board adds a micro color LCD screen directly to the PCB, allowing for the creation of compact touch interfaces. It also typically comes with a set of sensors such as an accelerometer and gyroscope, useful if you want to detect movement or tilt of the device as part of music control.
On the other hand, you have the ESP32-S3 development board with 1.75-inch circular AMOLED touchscreenIt also incorporates a dual microphone array and a 6-axis IMU, in addition to the previously mentioned battery. This design is clearly geared towards advanced portable devices, where the user interacts via a round touchscreen and the system can capture audio and motion.
Faced with these alternatives, an AMYboard ESP32-S3 designed as a synthesizer with MIDI and CV would likely prioritize having more accessible pins, clear CV connections, possible analog inputs and dedicated outputs to external hardware control. For a project focused on a keyboard with Hall sensors, multiplexers, and perhaps CV outputs, that design philosophy is very convenient.
The conclusion of this comparison is that there isn't one "best" motherboard overall, but rather a better motherboard for each type of project. If your priority is building a flexible, expandable MIDI/CV controller with a strong focus on input/output hardwareThe AMYboard based on the ESP32-S3-WROOM makes a lot of sense. However, if you're looking for a device closer to a finished gadget, with a striking touchscreen, integrated microphones, and a ready-to-use battery, then boards with a 1.7″ touchscreen LCD or a 1.75″ circular AMOLED display might be more appealing.
Have you chosen the right sound card for your MIDI and CV project?
Returning to the initial question of whether you've "messed up" with the choice, everything we've seen suggests that you have. choice of an ESP32-S3-WROOM based board It is consistent with the requirements: MIDI via USB, future expansion to MIDI BLE, reading of Hall effect sensors with multiplexers and the possibility of integrating a screen and battery later.
The fear that "MIDI over USB won't even work on this board" is unjustified if your dev board properly exposes the ESP32-S3's native USB. This microcontroller is designed to function as a USB device and can implement a USB-MIDI interface without issue. We're not talking about a microcontroller limited to a serial bridge, but rather... a modern SoC with native USB OTG support.
Furthermore, your input design strategy using Hall sensors and 8:1 multiplexers is perfectly compatible with the ESP32-S3's GPIO capabilities. You're not pushing the hardware to its limits or relying on unusual workarounds: you're making good use of the microcontroller's resources to achieve velocity sensitivity and expressive keyboard behavior.
If at any point you want to expand the project with a small I2C display, the board will allow you to do so without much trouble. And if one day you decide to upgrade to a a more elaborate graphical interface with a touchscreen or circular AMOLED LCD, or a fully portable format with an integrated batteryYou can always migrate part of the firmware design to another ESP32-S3 board variant that includes those components natively.
Given all of the above, what you have before you is not a dead end, but a solid foundation for a A modern, scalable synthesizer controller with MIDI and CV, well-aligned with the current capabilities of the ESP32-S3 ecosystem.Having USB-MIDI, BLE, sufficient processing power, and headroom for screens and battery gives you plenty of freedom to refine and expand your project without having to switch platforms halfway through.