We’ve previously covered WiFi buttons based on ESP8266 processor, but Seeed Studio has just launched ReButton “developer device” that serves the same purpose but features STM32 based MXCHIP EMW3166 WiFi module instead, exposes one I2C grove connector, and is preloaded with sample firmware that triggers Azure IoT Central or Azure IoT Hub.
ReButton hardware specifications:
- MCU module – MXCHIP EMW3166 module including STM32F412 Arm Cortex M4F MCU @ 100 MHz with 256KB SRAM, 1MB+2MB SPI Flash, and Cypress BCM43362 WiFi chip
- Input – 1x Push button
- Output – 1x RGB LED
- Extension – 1x I2C Grove connector (3.3V I/O)
- Debugging – 1x SWD pads, 1x UART for debugging
- Misc – 1x Jumper switch
- Power supply
- 2x AAA Alkaline batteries (LR03)
- Internal supply voltage – 3.3V
- Dimensions – 70 x 70 x 25mm
The ReButton comes preloaded with an Arduino sketch that handle key presses and send a trigger to Azure IoT Central or Azure IoT Hub. Documentation on Github describes the basic operation of the app after initial WiFi configuration:
- When you push ReButton, it will power up and connect to Internet via pre-configured Wi-Fi.
- ReButton will receive Device Twin changes from pre-configured Azure IoT Central or Azure IoT Hub.
- ReButton will send Device to Cloud Message to pre-configured Azure IoT Central or Azure IoT Hub.
- After D2C (Device To Cloud) message is sent, ReButton will shutdown.
The app supports single click, double click, triple click, long press (>3sec.) and super long press (>6sec.) so you can generate 5 types of events from the sample app.ReButton can be programmed via the Arduino IDE, and supports OTA firmware update. More advanced users can add they own I2C sensors, and program/debug the board via the SWD pin using openOCD.
The project is open source hardware with the EAGLE schematics and PCB layout, as well as the 3D STP design file for the housing are also available in Github.
ReButton is going for $24.95 plus shipping, which makes it mostly interesting for it’s easy integration with Azure IoT services, or to evaluate EMW3166 WiFi module, since you’ll now find ESP8266 WiFi buttons for under $10 plus shipping.