Description The M5Stack Stopwatch Dev Kit is a compact round ESP32-S3 development kit for portable interfaces, smart badges, wearable-style prototypes and lightweight IoT terminals. It combines an ESP32-S3R8 controller, 16MB Flash, 8MB PSRAM, a 1.75-inch 466 x 466 AMOLED touch display, Wi-Fi, battery operation, audio, motion sensing and expansion interfaces in a handheld form factor. Unlike a bare controller board, the M5Stack Stopwatch Dev Kit gives developers a finished interaction platform with touch input, two programmable buttons, a power button, vibration feedback, MEMS microphone, speaker amplifier path, RTC and IMU. That makes the M5Stack Stopwatch Dev Kit useful for UI-heavy prototypes where the enclosure, screen, power system and feedback hardware should already be integrated. The official documentation also exposes pin maps, model-size files, datasheets, Arduino examples, UiFlow2 quick-start material and ESP-IDF demo repositories. For teams building portable control panels or connected display devices, this kit shortens early hardware evaluation while keeping access to M5Stack's familiar software stack. Features ESP32-S3R8 platform: dual-core Xtensa LX7 controller up to 240MHz with 16MB Flash and 8MB PSRAM. Round AMOLED touch UI: 1.75-inch 466 x 466 AMOLED display with CST820B touch controller. Portable interaction hardware: two programmable buttons, one power button, vibration motor and lanyard hole. Audio and sensing: ES8311 codec, MEMS microphone, AW8737A amplifier, BMI270 IMU and RX8130CE RTC. Expansion-ready design: HY2.0-4P expansion interface plus rear 2.54mm expansion bus. Power management: M5PM1 multi-level power management with built-in 450mAh battery and USB Type-C 5V input. Development resources: official docs, model-size PDF, Arduino libraries, UiFlow2 support and ESP-IDF demos. Specifications Product name M5Stack Stopwatch Dev Kit (ESP32-S3) SKU M5-C152 Main controller ESP32-S3R8 dual-core Xtensa LX7, up to 240MHz Memory 16MB Flash, 8MB PSRAM Wireless 2.4GHz Wi-Fi Display 1.75-inch AMOLED round touch display, 466 x 466 resolution, CO5300 driver, QSPI interface Touch controller CST820B Buttons 2 x programmable buttons, 1 x power button Haptics Built-in vibration motor Audio ES8311 audio codec, MEMS microphone, AW8737A amplifier Sensors and RTC BMI270 IMU, RX8130CE RTC Expansion HY2.0-4P, rear expansion bus 2.54-7P and 2.54-6P Power management M5PM1 multi-level power management Battery 450mAh built-in battery Input power USB Type-C DC 5V Product size 52.0 x 52.0 x 15.5mm Product weight 39.0g Package size 70.0 x 70.0 x 23.6mm Gross weight 49.5g Applications Portable smart device prototypes with a round touch display. Electronic badge, wearable-style interface and compact dashboard projects. Lightweight IoT terminals that need Wi-Fi, battery power and local feedback. Touch-based control panels for demos, education and rapid UI validation. ESP32-S3 audio, IMU, RTC and power-management development experiments. Product List Package content: 1 x StopWatch development kit. Other Content Hardware overview: the official detail images show the round AMOLED front, the compact side profile, the rear PCB area and the rear expansion layout. Mechanical and weight reference: the model-size and weight images help customers confirm installation space, wearable-style mounting and package planning before choosing the M5Stack Stopwatch Dev Kit. Usage notes: M5Stack documents development notes and software resources for Arduino, UiFlow2 and ESP-IDF workflows. The M5Stack Stopwatch Dev Kit is best selected when a project needs a finished round touch interface rather than a minimal headless ESP32-S3 controller. Important search terms for this product include M5Stack StopWatch, ESP32-S3 development kit, round AMOLED touch display, portable IoT terminal, wearable interface prototype, ESP32-S3 touch board, M5Stack C152 and battery powered ESP32-S3 kit. Resources Official M5Stack StopWatch documentation M5Stack StopWatch PDF documentation StopWatch model size PDF StopWatch factory firmware GitHub StopWatch low-power test example M5Unified driver library M5GFX display library M5PM1 power management library M5IOE1 IO expansion library For a practical buying and project overview, read the same-site M5Stack StopWatch hands-on guide. FAQ What is the M5Stack Stopwatch Dev Kit used for?It is used for portable ESP32-S3 projects that need a round AMOLED touch display, buttons, audio, IMU, RTC, vibration feedback and battery power in one compact kit. Does it include a battery?Yes. The official specification lists a built-in 450mAh battery with M5PM1 multi-level power management. Which display does it use?It uses a 1.75-inch round AMOLED touch display with 466 x 466 resolution and a CO5300 display driver. Can I develop with Arduino or UiFlow2?Yes. M5Stack provides Arduino, UiFlow2 and ESP-IDF resources for StopWatch development. What is included in the package?The official package list includes one StopWatch development kit.
