# TinyS3[D] ESP32-S3 by Unexpected Maker > The TinyS3[D] is Unexpected Maker's ultra-compact ESP32-S3 board in the TinyPICO form factor, featuring a dual antenna system (onboard + u.FL, software-switchable), I2C battery fuel gauge, 8MB flash, 8MB PSRAM, LiPo charging, and 17 GPIO pins — all in a tiny castellated module. ## Quick Facts - **Brand:** Unexpected Maker - **Board Type:** ESP32-S3 - **Price:** ~$21.5 - **Product Readiness:** developer - **CPU:** Xtensa LX7 dual-core @ 240MHz, FPU, AI vector extensions, HW crypto (AES/SHA/RSA) - **CPU Architecture:** Xtensa LX7 dual-core - **CPU Cores:** 2 - **RAM:** 512KB SRAM + 8MB PSRAM - **PSRAM:** 8MB QSPI - **Flash:** 8MB - **USB:** USB-C (native USB + USB Serial JTAG) - **Power:** USB-C 5V or LiPo battery - **Operating Voltage:** 3.3V GPIO - **Antenna:** u.FL + onboard PCB antenna (switchable) ## Connectivity - **Wifi:** 2.4GHz 802.11 b/g/n - **Bluetooth:** BLE 5.3 ## Open Source - **Firmware:** Yes - **Schematics:** Yes - **PCB Layout:** Yes ## Certifications CE, FCC, RoHS ## Compatible Firmware circuitpython, micropython, arduino, esp-idf ## Use Cases - iot - prototyping - wearable - smart-home ## Components - **ESP32-S3** (mcu): Dual-core Xtensa LX7 at 240MHz with AI vector extensions, WiFi 802.11 b/g/n, Bluetooth 5 LE, and native USB OTG. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.espressif.com%2Fsites%2Fdefault%2Ffiles%2Fdocumentation%2Fesp32-s3_datasheet_en.pdf&ref=openhardware.directory&product=tinys3d-esp32-s3&source=md-export) - **8MB PSRAM** (memory): External 8MB QSPI pseudo-static RAM providing expanded dynamic memory in an ultra-compact form factor. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fwww.espressif.com%2Fsites%2Fdefault%2Ffiles%2Fdocumentation%2Fesp32-s3_datasheet_en.pdf&ref=openhardware.directory&product=tinys3d-esp32-s3&source=md-export) - **I2C Battery Fuel Gauge** (sensor): Dedicated I2C fuel gauge IC for accurate LiPo battery state-of-charge monitoring in portable applications. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fesp32s3.com%2Ftinys3.html&ref=openhardware.directory&product=tinys3d-esp32-s3&source=md-export) - **RF Switch** (chip): Software-controlled RF switch for runtime selection between onboard antenna and u.FL external antenna. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fesp32s3.com%2Ftinys3.html&ref=openhardware.directory&product=tinys3d-esp32-s3&source=md-export) - **Low-power RGB LED** (led): Ultra-low current RGB LED for status indication, visible even in deep-sleep modes with minimal power overhead. — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fesp32s3.com%2Ftinys3.html&ref=openhardware.directory&product=tinys3d-esp32-s3&source=md-export) ## Protocols - **I2C**: SDA: GPIO21, SCL: GPIO22 - **SPI**: MOSI: GPIO34, MISO: GPIO35, SCK: GPIO36, CS: GPIO37 - **UART**: TX: GPIO43, RX: GPIO44 - **PWM** ## GPIO Map | Pin | Name | Type | Functions | |-----|------|------|-----------| | GPIO1 | ADC1_CH0 | GPIO | analog, digital | | GPIO2 | ADC1_CH1 | GPIO | analog, digital | | GPIO3 | ADC1_CH2 | GPIO | analog, digital | | GPIO5 | GPIO5 | GPIO | digital | | GPIO6 | GPIO6 | GPIO | digital | | GPIO7 | GPIO7 | GPIO | digital | | GPIO8 | GPIO8 | GPIO | digital | | GPIO9 | GPIO9 | GPIO | digital | | GPIO21 | SDA | I2C | i2c-sda, digital | | GPIO22 | SCL | I2C | i2c-scl, digital | | GPIO34 | MOSI | SPI | spi-mosi, digital | | GPIO35 | MISO | SPI | spi-miso, digital | | GPIO36 | SCK | SPI | spi-sck, digital | | GPIO37 | CS | SPI | spi-cs, digital | ## Available Software - **[CircuitPython](https://openhardware.directory/r?to=https%3A%2F%2Fcircuitpython.org%2Fboard%2Funexpectedmaker_tinys3%2F&ref=openhardware.directory&product=tinys3d-esp32-s3&source=md-export)** - **[Getting Started Guide](https://openhardware.directory/r?to=https%3A%2F%2Fesp32s3.com%2Ftinys3.html&ref=openhardware.directory&product=tinys3d-esp32-s3&source=md-export)** ## Description ## Overview The TinyS3[D] is the smallest member of Unexpected Maker's [D]-series, fitting the power of the ESP32-S3 into the compact TinyPICO form factor — the same footprint as the original TinyPICO and TinyS2. Despite its tiny size, it carries both the dual-core Xtensa LX7 processor at 240MHz and 8MB of QSPI PSRAM, making it one of the most capable ultra-compact ESP32-S3 boards available. The [D] designation brings two key hardware upgrades over earlier TinyS3 revisions: a dual antenna system combining an onboard high-gain 3D PCB antenna with a u.FL connector for an external antenna, switchable at runtime through an RF control pin; and a dedicated I2C battery fuel gauge for accurate LiPo state-of-charge readings. These additions make the TinyS3[D] well-suited for space-constrained portable and wearable applications that still demand robust wireless performance. With 8MB of flash and 8MB of PSRAM on an 8MB + 8MB configuration, the TinyS3[D] provides ample storage and dynamic memory for CircuitPython applications even at this reduced size. A total of 17 GPIO pins are broken out, the board includes a low-power RGB LED (visible with dramatically reduced current for deep-sleep awareness), and the USB-C connector provides native USB CDC and USB Serial JTAG for programming and debugging. LiPo battery charging via a 700mA 3.3V LDO completes the power management picture. The TinyS3[D] ships with CircuitPython and a UF2 bootloader. It supports Arduino (2.0.3+), ESP-IDF, and MicroPython, and is pin-compatible with TinyPICO and TinyS2 designs. Unexpected Maker provides open-source schematics on GitHub and full documentation at esp32s3.com. ## Where to Buy - [Adafruit](https://openhardware.directory/r?to=https%3A%2F%2Fwww.adafruit.com%2Fproduct%2F6401&ref=openhardware.directory&product=tinys3d-esp32-s3&source=md-export) — $21.50 ## Resources - [product](https://openhardware.directory/r?to=https%3A%2F%2Fwww.adafruit.com%2Fproduct%2F6401&ref=openhardware.directory&product=tinys3d-esp32-s3&source=md-export) - [github](https://openhardware.directory/r?to=https%3A%2F%2Fgithub.com%2Funexpectedmaker%2Fesp32s3&ref=openhardware.directory&product=tinys3d-esp32-s3&source=md-export) - [wiki](https://openhardware.directory/r?to=https%3A%2F%2Fesp32s3.com%2Ftinys3.html&ref=openhardware.directory&product=tinys3d-esp32-s3&source=md-export) ## Tags `unexpected-maker`, `esp32-s3`, `tinys3`, `tiny`, `psram`, `dual-antenna`, `circuitpython`, `wifi`, `ble`, `ufl`, `wearable` ## Images ![TinyS3[D] ESP32-S3 by Unexpected Maker](https://nbg1.your-objectstorage.com/openhardware-directory/entities/tinys3d-esp32-s3/b37122ee4b5d.jpg) ![TinyS3[D] ESP32-S3 by Unexpected Maker](https://nbg1.your-objectstorage.com/openhardware-directory/entities/tinys3d-esp32-s3/4124d069d134.jpg) ![TinyS3[D] ESP32-S3 by Unexpected Maker](https://nbg1.your-objectstorage.com/openhardware-directory/entities/tinys3d-esp32-s3/5e1ef300c551.jpg) --- [View full device page](https://openhardware.directory/devices/tinys3d-esp32-s3)