M5Stack Stamp-S3A, also known as M5StampS3A, is an update to the M5Stamp S3 ESP32-S3 module introduced in 2023 with an optimized antenna design, lower power consumption, a larger user button, and a different logic for the RGB LED control.
Other features remain the same with 8MB Flash, RGB LED, input button, and 23 GPIOs all in a tiny 26 x 18mm form factor. Two versions are available: the Stamp-S3A without pre-soldered headers and the Stamp-S3A PIN1.27 with headers soldered on the board and an orange heat-resistant cover.
M5Stamp-S3A specifications:
- WiSoC – Espressif Systems ESP32-S3FN8
- CPU
- Dual-core 32-bit Xtensa LX7 microcontroller with AI vector instructions up to 240MHz
- RISC-V ULP co-processor
- Memory – 512KB SRAM
- Storage – 8MB flash
- Wireless – 2.4GHz WiFi 4 (802.11b/g/n), Bluetooth 5.0 LE + Mesh
- CPU
- Connectivity
- 2.4 GHz WiFi 4, 20 MHz and 40 MHz bandwidth, IEEE 802.11 b/g/n protocol, up to 150 Mbps
- Bluetooth 5, Bluetooth Mesh, with support for 125 Kbps, 500 Kbps, 1 Mbps, 2 Mbps bitrate, long-range support
- 2.4GHz 3D antenna
- USB – 1x USB Type-C port for power and programming
- Expansion
- 2.54mm and 1.27mm pitch headers and castellated holes with
- Up to 23x GPIOs
- SD/SDIO/MMC
- Touch sensor
- SPI master/slave
- EMAC
- Motor PWM, LED PWM
- UART, I2C, I2S, pulse counter
- Optional 8-pin or 12-pin FPC connector with GPIO, LCD interface
- 2.54mm and 1.27mm pitch headers and castellated holes with
- Misc – 1x user button, 1x user RGB LED (WS2812B-2020)
- Power Supply
- Input – 5V @ 500mA via USB-C port
- MUN3CAD01-SC 5V to 3.3V DC/DC converter
- Dimensions – 26 x 18 x 4.7 mm or
- Weight – About 3 grams
- Temperature Range – 0 to 40°C
If we just look at the specifications, we won’t see any changes compared to the original M5Stamp S3 module. So we need to look into smaller details to spot the differences. First, the button is now larger with an “improved tactile feel” at 4.0 × 3.0 × 2.0 mm instead of 2.6 × 1.6 × 0.55 mm. Power consumption has improved quite a lot in sleep mode, both from the USB-C port (5V @ 88.82uA vs 400.67uA) and the Vin pin (5V @ 6.84uA vs 310.89uA). Standby mode at 5V is now 25.54mA via USB-C and 25.53mA via Vin, against about 33mA for the older model
The behavior of the RGB LED power has also changed. It used to be powered up as soon as power was applied to the board, but it’s now multiplexed with the reserved screen FPC bus backlight. The 3D antenna design has changed as shown in the photo below. The new design is said to enable better signal reception, but I’m not knowledgeable enough to explain why that may be the case. Feel free to chime in if you can explain what’s going on here…
Software support has not changed, and the ESP-IDF framework, PlatformIO, the Arduino IDE, and the web-based UIFlow visual programming platform are supported. You’ll find the full details, including the schematics and instructions to get started with the Arduino IDE or UIFlow2, on the documentation website.
M5Stack sells the new Stamp-S3A modules on its online store for $7.50, and they should eventually surface on the company’s AliExpress and Amazon stores.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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New 3D antenna?! ROFL, that’s a bog standard PIFA or planar inverted-F antenna, which costs 20 cents at the most. There’s nothing special about them and they’re used in low cost products because you can make a ton of them for the cost of renting a metal stamping and folding machine for a single day.
Yes, there are a lot of different designs and the new one might very well be a lot better than the old one, but the marketing just sucks.
Antenna design is equal parts black magic and voodoo, some companies are great at it, other suck. A company I worked for wanted to try and design some PCB antennas, based on antenna science, two out of 100 worked, both poorly compared to something that cost the company 50 cents to buy.
Without seeing a test diagram of the antennas in question, it’s impossible to know how well they work, or not.
Thanks for the explanation. Regarding the “3D antenna”, almost all board vendors using this type of antenna simply call them “3D antenna”. It’s not really a new or unusual marketing term.
That’s bizarre, are there any non 3D antennas? I guess they don’t count PCB antennas as 3D, but even those ones aren’t entirely flat.
Yes — other than PCB or “3D” metal antennas, there’s also plain ceramic antennas (the very compact, space-saving, tiny rectangle blocks).
M5stack is right to market the antennas they use as “special”, in the sense that none of the competing products from other Maker houses use the 3D metal types for small dev boards like this:
• SparkFun’s ESP32 boards generally use the Espressif modules with included PCB antennas. In my experience, they have excellent performance.
• Waveshare’s Mini and Zero stamp-sized ESP32 boards all use ceramic antennas. In my experience, they have excellent performance.
• Seeed’s Xiao stamp-size boards use ceramic antennas and/or provide an antenna port for an external antenna. In my experience, the one that comes with the C6 has excellent performance.
• Adafruit’s QT Py Xiao-compatible stamp-size boards use ceramic antennas that tend to be on the weaker side (and in the case of the C3, absolutely atrocious and unreliable).
M5Stack’s NanoC6 also uses a ceramic antenna (with excellent performance), though I imagine they would have used the “3D” metal one if this particular board weren’t so insanely compact.
A chip antenna is still a 3D object, no? That was more my point.
Also, the industry term is PIFA not 3D metal antenna.
It looks like they’re either using a dual-antenna configuration or—(unlikely) 2 separate individual transceivers—if you look at the cutouts on the back of the board. Perhaps they’re supporting some kind of 2×2 format?
The older design seemed to just use a single antenna (single cutout) with a covered wire that wrapped around the board to the chip—probably caused a lot of unintended parasitic loss from that design.