El M5StampS3 BAT module with ESP32-S3 and integrated battery It has become one of the most interesting options for those who want to build compact, efficient IoT projects with advanced power management. It's not simply "another ESP32": it combines a very powerful platform with an intelligent power system, ample memory, and a form factor designed for direct integration into custom boards or commercial products.
Furthermore, this module fits within a whole M5Stack device ecosystemsuch as the StampS3 "plain" or the unique Cardputer also based on ESP32-S3. Understanding what each one brings to the table helps in choosing the right option for the project: from a minimal "brain" soldered onto a PCB, to a pocket-sized mini-computer with integrated keyboard, screen and batteries ready to tinker with WiFi, Bluetooth or even do penetration testing.
What is the M5StampS3 BAT and how does it differ?
The M5StampS3 BAT is a embedded module with integrated power management It uses the ESP32-S3-PICO-1-N8R8 SiP as its core. This System-in-Package integrates the ESP32-S3 with a dual-core Xtensa LX7 CPU of up to 240 MHz, along with 8 MB of Flash memory and 8 MB of PSRAM, into a single package, making it ideal for edge processing tasks, basic vision, lightweight AI, or intensive data handling.
Unlike the standard StampS3, the BAT model adds specific circuitry for battery and power controlIt incorporates the M5MP1 power management design (also referred to as M5PM1 in some texts), which allows for the management of power input and output, LiPo battery charging, and the measurement of input and battery voltages. All of this makes it a perfect candidate for portable devices that need to operate for extended periods with reduced power consumption.
Another key difference of the M5StampS3 BAT compared to other variants is the presence of an integrated power interface for 3,7v batteriesDesigned to connect via a specific connector (an SH1.0 battery cable is included in the package). This covers the complete cycle: USB-C or 5V power, LiPo battery, and fine-tuning of the power status.
The module displays a total of 11 general-purpose GPIO pins and 1 wake-up pinThese are accessible via a 24-pin BTB connector with a standard 2,54 mm pitch on "half-hole" (castellated) pads. This facilitates both SMT assembly on a custom PCB and use in DIP format or with pins for rapid prototyping.
Another key difference of the M5StampS3 BAT compared to other variants is the presence of an integrated power interface for 3,7V batteriesDesigned to connect via a specific connector (an SH1.0 battery cable is included in the package). This covers the complete cycle: USB-C or 5V power, LiPo battery, and fine-tuning of the power status.
Internal architecture: ESP32-S3-PICO-1-N8R8, memory and connectivity
At the core of the module we find the ESP32-S3-PICO-1-N8R8A highly integrated version of the ESP32-S3 that combines CPU, memory, and analog elements into a single SiP. The CPU is a dual-core Xtensa LX7 with a 32-bit architecture and a maximum frequency of 240 MHz, ensuring ample headroom for complex real-time tasks, communications, and application logic.
At the memory level, this SiP provides 8 MB of Flash and 8 MB of PSRAM already integrated into the module itself, without the need for external chips. Flash is used to store firmware and persistent data, while PSRAM is essential for applications that require many buffers, AI libraries, audio or video processing (for example, with DVP cameras connected via the BTB connector that supports that interface).
Regarding wireless connectivity, the M5StampS3 BAT inherits the battery from the ESP32-S3 and supports 2,4 GHz Wi-Fi (802.11 b/g/n) for robust links in local area networks and the Internet of Things. This connectivity makes it suitable for home automation, remote telemetry, industrial data logging, small embedded web servers, or cloud-connected devices.
The module design is prepared to handle AI inference tasks at the edge and high-rate data transmission, leveraging both dual-core computing power and the Flash + PSRAM combination. This opens the door to using frameworks and examples from Espressif or the community for lightweight recognition, intelligent sensor filtering, or local analysis before uploading information to the network.
Power and battery management integrated into the M5StampS3 BAT
One of the great strengths of the M5StampS3 BAT is its M5MP1 power management circuitThis design provides a multi-stage system for controlling both the power input and the supply to the ESP32-S3 and associated peripherals. It is intended to work with 3,7V lithium batteries, as well as 5V inputs from USB Type-C or standard DC power.
The module has a battery-specific interface for easily connecting an external LiPo battery (3,7V). Furthermore, the circuit automatically manages charging when the device is powered via USB-C or 5V, safely controlling the process and monitoring key states such as input voltage and battery voltage.
Another important feature is the support for low power wake-up functionsThe module has a dedicated wake-up pin that allows the ESP32-S3 to be brought out of deep sleep states. This allows the electronics to remain in low-power mode most of the time, waking up only when an external event (sensor, button, signal from another device) requires it.
Once the microcontroller enters low-power mode, it can reactivate the main power supply via the wake-up I/OThis reduces overall power consumption and extends battery life. This is especially useful in projects such as remote sensors, standalone data loggers, or portable devices that spend most of their time inactive.
Physical interface: GPIO, BTB connector and RGB LED
The M5StampS3 BAT makes available to the developer 11 universal GPIOs plus 1 wake-up lineThis is sufficient for a large number of control projects, sensor reading, or connections with other modules. Although the number of pins is lower than in a "bare" StampS3 (which has up to 23 GPIOs), this BAT version prioritizes the integration of power electronics and a compact format for applications where fewer pins are required.
The pins are exposed by means of a 24-pin BTB connector It also supports the DVP interface for cameras or other high-speed peripherals. The module uses a half-hole pad design with a standard 2,54 mm pitch, allowing it to be soldered using SMT techniques in production or on breadboards or carrier boards with DIP rows.
The module itself also includes a programmable RGB LEDThis small detail is very useful in practice because it allows you to indicate system statuses (WiFi connection, error, battery charge, configuration mode, etc.) without the need for external components. From the firmware, you can control its color and brightness using typical WS2812B smart LED protocols.
The combination of castellated pads, 2,54 mm pitch and BTB connector allows different integration strategies: solder it directly to an end board, keep it removable using pressure connectors, use it as a "plug-in" module for prototypes, or even integrate it into mass-produced products, minimizing the complexity of the main PCB design.
Kit contents and typical applications of the M5StampS3 BAT
The basic M5StampS3 BAT package usually includes the module itself and an SH1.0 battery cableThis cable allows for the convenient connection of a 3,7V LiPo cell. It simplifies the assembly of prototypes and final products, eliminating the need to search for separate compatible connectors.
In terms of uses, the manufacturer primarily directs it to IoT development projectsThanks to the combination of WiFi, ample memory, dual-core CPU and advanced power management, it is well suited to smart sensor nodes, home device controllers, connected wearable devices or small data gateways.
The fact of having integrated battery charge control and voltage measurement It simplifies the implementation of features such as displaying battery level, activating low-power modes when the voltage drops too low, or recording energy status as part of the data sent to the cloud. All of this without adding any specific external chips.
Its small size and the possibility of easily soldering it make it a very attractive option for integrating it into commercial productsThis approach aims to reduce development time and certify fewer components. Designing a PCB that "houses" the StampS3 BAT as if it were just another component allows developers to focus on the product's logic and specific hardware (sensors, actuators, connectors) while reusing a proven platform.
The M5Stack ecosystem: StampS3 and Cardputer as a reference
To better understand the role of the M5StampS3 BAT, it's worth taking a look at other related products from M5StackOne of them is the "classic" StampS3, a very compact embedded module also based on ESP32-S3FN8, but with a somewhat different philosophy: maximizing the number of GPIOs and offering a minimal ready-to-use system on 5V.
The StampS3 is designed as a minimum system board It includes an integrated MUN3CAD01-SC DC/DC regulator that reliably converts 5V to 3,3V. This ensures dependable operation even with slight variations in the input. The module provides 23 ESP32-S3 GPIO pins, accessible via 1,27mm or 2,54mm headers, supporting SMT, DIP strip, and jumper wire connections.
Among its additional features we find a WS2812B-2020 programmable RGB LED and a user buttonwhich facilitate basic control and interaction without the need for extra hardware. The wireless antenna is a 2,4 GHz 3D antenna and exposes interfaces such as UART, I2C, I2S, SPI, SD/SDIO/MMC, PWM, touch sensor, EMAC, and other typical ESP32-S3 functions, with pins G0 to G15 and G39 to G46 available.
The StampS3 module comes ready to be installed in download or programming mode Holding down the G0 button while powering on is a useful detail when flashing low-level firmware or working with Espressif's IDF. Its dimensions are very small (26 x 18 x 5 mm) and it weighs barely 3,2 grams, making it ideal for projects and components for wearablesmedical equipment or compact automation devices.
In terms of programming, the StampS3 supports Arduino, PlatformIO, the Espressif IDF, and graphical environments like M5Stack's UIFlowIn other words, it can be used in both "maker" projects and professional developments, taking advantage of its affordable price (around $7,50) and its high computing power within a minimal size.
StampS3 vs. M5StampS3 BAT: Similarities and Differences
Although they share the same ESP32-S3FN8 core While sharing similar philosophies (compact embedded modules), the StampS3 and M5StampS3 BAT have slightly different approaches. The StampS3 focuses on providing maximum I/O and a minimal 5V to 3,3V solution, with most of the microcontroller's pins exposed.
The M5StampS3 BAT, for its part, sacrifices some of those GPIO pins to include a more advanced power management system and direct battery supportThis makes it especially suitable for portable devices powered by LiPo batteries where battery life, controlled charging, and low power mode are priorities.
Both share characteristics such as 2,4 GHz WiFi compatibility, integrated 3D antenna, RGB LED and programmable button (In the case of the StampS3, this is clearly documented, and the BAT retains at least the RGB LED). They also retain the use of castellated pads and connection options for both 2,54 mm and, in some models, 1,27 mm.
In practical terms, we could say that the StampS3 is ideal when you need a “brain” with many input/output pins and you have control of the external power supply, while the M5StampS3 BAT shines in projects that require Flexible power supply with integrated battery, recharging and fine-tuning of consumption without adding additional power components.
Cardputer: the pocket-sized mini-computer with ESP32-S3
Within the M5Stack universe, the following deserves special mention: CardputerThe Cardputer, while not the M5StampS3 BAT, uses the ESP32-S3 and serves as an example of how far this microcontroller can be integrated into end products. It's essentially a small pocket computer with a case slightly larger than a credit card, a QWERTY keyboard, and an integrated battery.
Inside, it houses a SoC. ESP32-S3FN8 It features a dual-core Xtensa LX7 CPU at 240 MHz and 8 MB of Flash memory. It has a 1,14-inch color LCD screen with an ST7789V2 controller and a resolution of 240 x 135 pixels, ideal for simple interfaces, menus, basic graphics, or small data dashboards. The keyboard has 56 keys in a 4 x 14 matrix, with an actuation force of approximately 160 gf.
In terms of expansion, the Cardputer integrates HY2.0-4P connectors and a 2,54 mm 14-pin EXT portDesigned to accommodate additional sensors, external modules, or peripherals. It includes an infrared emitter (IR LED) that allows the device to be used as a remote control for televisions, air conditioners, and other equipment that supports IR control.
In the audio section, it has ES8311 codec, NS4150B amplifier and 8 Ω / 1 W speakerIn addition to a MEMS microphone with a 65 dB SNR, it allows for the development of recording and playback projects, simple voice assistants, or communication applications. It also integrates a BMI270 IMU inertial sensor, which expands the possibilities in interactive and motion projects.
In terms of energy, the Cardputer incorporates two rechargeable LiPo batteries with a total capacity of 1750 mAhproviding considerable battery life for portable use. Standby power consumption with the switch off is around 0,23 µA, while in normal operation it is around 120,2 mA at 4,2 V, increasing to 132,3 mA with WiFi and around 154,6 mA with BLE active. All this in a size of approximately 84 x 54 x 19,6 mm and a weight of 81 g.
Connectivity, software and advanced uses of the Cardputer
In terms of wireless connectivity, the Cardputer offers WiFi and Bluetooth thanks to the ESP32-S3This, combined with its portable format, makes it a kind of "Swiss Army knife" for mobile projects. It also includes a microSD card slot, allowing for the storage of large amounts of data, logs, or applications.
The device can be programmed using Arduino or the Espressif IDFM5Stack also provides extensive documentation and community resources, along with the M5Burner tool, which makes it easy to load various pre-designed firmwares onto the Cardputer with just a few clicks.
Among those firmwares is the well-known Evil-CardputerIt's geared towards penetration testing of WiFi networks and Bluetooth devices, always for ethical use and security testing. There are also recreational firmwares, such as playable versions of DOOM or Game Boy emulators, demonstrating the chip's power and the platform's capabilities.
The combination of a full keyboard, screen, audio, expansion, and connectivity makes the Cardputer ideal for remote controllers, configuration terminals, field diagnostic tools, test platforms or simply as a technological toy to explore the potential of the ESP32-S3. Its integrated charger allows the batteries to recharge automatically when the device is connected via USB, simplifying daily use.
The “pure” M5StampS3: detailed technical specifications
Returning to the standard M5StampS3, it is worth reviewing its features in some detail. technical characteristics because they serve as a basis for understanding the platform on which the BAT model is based. The SoC is an Espressif Systems ESP32-S3FN8 with a 32-bit dual-core Xtensa CPU at 240 MHz, offering 384 KB of ROM and 512 KB of internal SRAM.
This base is complemented by 8 MB of external Flash memoryThis is sufficient for the vast majority of projects, even when using heavy libraries or multiple firmwares. In terms of connectivity, the module supports 2,4 GHz 802.11 b/g/n WiFi with speeds up to 150 Mbps, and Bluetooth 5 with Mesh support, from 125 Kbps to 2 Mbps, using an integrated 2,4 GHz 3D antenna.
The peripherals section is particularly rich: the M5StampS3 offers 23 GPIO pins numbered from G0 to G15 and from G39 to G46It supports standard interfaces such as UART, I2C, I2S, SPI, PWM, pulse counter, SD/SDIO/MMC master control, and a touch sensor. Additionally, an 8- or 12-pin FPC connector is mentioned, which can be used to expose additional GPIO pins or an LCD interface.
At a physical level, the module has Castellated pads with pitches of 2,54 mm and 1,27 mmThis allows it to be soldered directly onto carrier boards or connected via jumper wires or headers. It includes a user button and a WS2812B-2020 RGB LED, both very useful for basic interaction and system status indication.
Feeding is done through a MUN3CAD01-SC DC/DC regulator It converts 5V to 3,3V, with a typical current of up to 500mA through USB-C. As mentioned, its dimensions are 26 x 18 x 5 mm and it weighs 3,2g. The typical operating temperature range is 0 to 40°C, sufficient for most indoor applications and some controlled outdoor uses.
User experience, programming, and documentation
One of the strengths of the M5Stack ecosystem, for both the M5StampS3 BAT and the StampS3 and Cardputer, is the broad compatibility with popular development environmentsThey can be programmed from the Arduino IDE, using PlatformIO, or you can work directly with the Espressif IDF if finer control and access to all low-level APIs are required.
In addition, M5Stack offers UIFlow, a graphical programming environment Designed to simplify development, this tool is especially useful for teaching, rapid prototyping, or users who don't want to delve deeply into C/C++. It makes it easy to create logic flows, integrate sensors, and control outputs without requiring extensive prior experience in embedded programming.
Community support is also a factor to consider: there are numerous examples, tutorials and libraries These designs already incorporate the ESP32-S3, WiFi and Bluetooth management, SD card storage, addressable LEDs, an LCD screen, IMU sensors, and other common peripherals. This significantly reduces the learning curve and the time required to develop a functional prototype.
In the specific case of the M5StampS3 and the BAT model, the fact of having USB Type C with integrated UART converter In some models, it makes programming and serial communication as simple as connecting the cable to the computer, which is a clear advantage over more basic boards that require an external programmer or additional adapters.
Finally, the manufacturer himself complements the products with Documentation on power supply, diagrams, connection examples and application notesThis helps both makers and engineers to integrate these modules into projects safely and efficiently. And, if they go into production, the standardization of the form factor and manufacturing quality also work in their favor.
Taken together, the M5StampS3 BAT and the rest of the modules and devices in the M5Stack family form a A very robust platform for designing IoT devices, wearables, and embedded deviceswhere a powerful ESP32-S3, ample memory, wireless connectivity, advanced power management, and a software and documentation ecosystem are combined, making it much easier to focus on the project idea instead of struggling with the basic hardware.
