M5Stack Stamp-C5, also known as the M5Stamp-C5, is a tiny wireless IoT USB-C board based on the Espressif ESP32-C5 RISC-V microcontroller with dual-band WiFi 6, Bluetooth LE, and 802.15.4 (Zigbee/Thread) connectivity.
Despite its small size (19.1 x 17.6mm), the module exposes up to nineteen GPIO pins, eleven on standard 2.54mm pitch headers and castellated holes, and eight on an FPC extension connector. The board also supports battery charging and ships with an external IPEX antenna for wireless connectivity, since there’s no built-in antenna.
M5Stack Stamp-C5 specifications:
- Wireless MCU – Espressif Systems ESP32-C5HF4
- CPU
- Single-core 32-bit RISC-V processor @ up to 240 MHz
- Low-power RISC-V core @ 48 MHz acting as the main processor for power-sensitive applications
- Memory – 384 KB SRAM on-chip
- Storage – 320 KB ROM, 4MB SPI flash
- Wireless
- Dual-band (2.4/5 GHz) 802.11ax WiFi 6, 802.11b/g/n WiFi 4 backward compatibility
- WiFi modes: Station mode, SoftAP mode, SoftAP + Station mode, and promiscuous mode
- Bluetooth 5.0 Low Energy (LE) with Mesh support, up to 2Mbps data rate
- 802.15.4 radio for Zigbee 3.0, Thread 1.3, and Matter up to 250 Kbps
- CPU
- Antenna – IPEX-1 antenna connector with LFD182G45DCHD481 dual-band diplexer for 2.4/5 GHz selection
- USB
- USB Type-C port for power and programming
- D+/D- pads on the bottom of the board
- Expansion
- 2x 7-pin headers (through holes and castellated holes) with up to 11x GPIO, 5V (VUSB), 3.3V, VBAT, and GND
- 12-pin FPC connector with up to 8x GPIO, UART, 3.3V, GND
- Misc
- Charging and Boot/User (G28) LEDs
- Tx/Rx pads for debugging
- Boot and Reset pads
- Power Supply
- 5V via USB Type-C port
- 3.7V battery support via SGM40567-4.2XG/TR charging IC; Approx. 200mA charging current
- Consumption – Deep sleep: 3.7V @ 13uA
- Dimensions – 19.1 x 17.6 x 3.4mm
- Weight – 1.8 grams or 2.4 grams with headers
Two versions of the board are available: the Stamp-C5 as shown above, and the Stamp-C5 DIP with the 12-pin FPC connector soldered on, and two 7-pin headers (not soldered). M5Stack provides PDF schematics, a pinout diagram (see below), and instructions for getting started with the Arduino IDE on the documentation website.
The Stamp-C5 is the smallest ESP32-C5 USB-C IoT board/module we’ve seen so far, with the two closest competitors being the XIAO ESP32-C5 (21 x 17.8mm) with an ESP32-C5HR8 chip (8MB PSRAM) and an 8MB SPI flash) and the NiceMCU ESP32-C5 Mini (27.9 x 17.8 mm) based on the same ESP32-C5HF4, but with on-board antenna and IPEX connector, and no battery support. The Stamp-C5 offers more I/Os than either thanks to its extra FPC connector.
The company sells the Stamp-C5 for $6.50, and the DIP variant for $7.95 on the M5Stack store, and both should soon become available on the M5Stack AliExpress store.
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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What’s the bizarre obsession with tiny boards?
I won’t buy ESP32 boards without the following:
3-5 are not important for me but 8n general I agree, except for some very special cases, but probably then it would be more reasonable to usethe bare module over a ready made pcb
This product might not be for you – and that’s okay! Seeed’s XIAO range is also teeny-tiny, and massively popular (and used in multiple commercial products).
Some people need smol because they’re building tiny things, like hand-held buttons and sensors. If there wasn’t a market for small boards, they wouldn’t make them! 🙂
And you wouldnt actually use esp32 for sensors, due to the high power draw – even for ble.
It is not the old ESP32. The newer RISC based models are actually much better in low power and sleep modes. Of course, they are not comparable to the leaders in that area, but they are still good enough for many applications.
As arbu7as notes, Espressif’s chips are not marketing-leading in the power-sipping department. You won’t get nRF5x performance from them, but they’re more than good enough — and certainly cheaper.
Of course you would, and plenty of people do. They’re in millions of sensors worldwide!
Most recent ESP32 RISC-V parts come with low-power I2C ports & a secondary ultra-low power core, which is perfect for keeping an eye on sensors that phone home intermittently.
There’s a myriad of connectivity options, all with power-saving options: TWT (Target Wake Time) on WiFi 6 (saving power by foregoing network reassociation costs); Zigbee battery-powered device profiles; OpenThread SED (Sleepy End Device) support…
And as their latest SKUs are certified for Bluetooth 6, even ESP32-based BLE sensors benefit from power-saving features like DBAF, etc.
Would you know the best place to find developers with experience in ESP32-based hardware and the mobile apps that connect to it?
Wish these things came without the USB port and exposed more pins on the lower edge where the USB is instead of the pins on the underside.
A good tiny design would replace the USB-C connector with a small female header that connects an auxiliary board with the USB-C connector. nice-sized reset button, power LED, charge LED, a battery charger, and battery isolation circuit, leaving room on the main board for a nice-sized boot/user button, user LED, and Lipo connector. I also prefer an on-board PCB antenna over an external PCB antenna using the tiny fragile U.FL connectors with a very low number of connection cycles, and I won’t use boards with chip antennas
You only need one auxiliary board to support many tiny battery-powered boards. I charge batteries on a separate board or using a dedicated LiPo charger, not by stringing usb cables to the devices or taking them out of service for charging. I swap out low batteries for charged batteries.
The USB-C connector, reset button, power LED, charge LED, battery charger, and battery isolation circuit are useless when running your projects on battery. Why hasn’t somebody else thought of this? Seeed are you listening? I’m not using any more of your user-unfriendly XIAO boards.
You are clearly not the target audience for these boards, that does not make them user unfriendly. Lots of people including me love them.