Homely WSN - Basic Board V2 (ESP32-S2)

Homely WSN Basic Board V2 is an IoT board to collect environmental data (temperature, humidity, and pressure) and to push them to a centralized server through Wi-Fi. This is the enriched successor of the Basic Board V1, that improves different aspects: - energy efficiency (20uA during deep-sleep) - onboard recharge for single-cell Lipo battery - measurement of battery level based on voltage* - ESD protection - USB-C connector * Given the high non-linearity of the curve charge-voltage of Lipo battery, you will be able to provide only 3 battery states (i.e. high, medium, low). ## Main components - Espressif ESP32-S2 (ESP32-S2-WROOM or ESP32-S2-WROOM-I) - Digital temperature and humidity sensor Sensirion SHT30 - Digital temperature and pressure sensor Bosch BMP280 - Reset and User buttons - 32.768Hz crystal oscillator - Switch ON/OFF - Low quiescent current LDO Microchip MCP1700T - Lipo recharger Microchip MCP73837 - JST PH (2.0mm pitch) to connect the lipo battery - USB-C connector for power supply and to recharge the (optional) Lipo battery ## Assembling The entire board is manually assemblable, no stencil is required. Hot air gun will be necessary for BMP280, SHT30, MCP73837, and USB-C connector. Arduino sketches to test the PCB are available [here](https://github.com/fabianoriccardi/homely-wsn-basic-board-2-test). ## Usage ### Firmware upload Since there is no USB-Serial to flash ESP32-S2, you need an external one. The 6 pins needed to flash the board are identified by *PROG* label on the PCB. You may use [this programmer](https://easyeda.com/fabiano.riccardi/esp8266-programmer_copy), designed to be *pin-compatible* with this board. The firmware is under development, and it will be released after the first official release of Arduino core for ESP32-S2. ## About versions and board name *Basic Board V2* is the evolution of the original Basic Board V1, which basically renew all the hardware expect for the sensors. Hence, given the differences, I have started a new indipendent project that has *V2* in the name. However, these projects remain indipendent: when a project advances, it will continue with version 3, 4, 5,... but the name will not follow the versioning system. This project starts from version *2.0.0*. ## Changelog - 2.0.0 ✅: first version, I works but I would suggest to wait for next release that improve *solderability* - 3.0.0 ❔: work in progress, form factor will be changed ### Versioning conventions Each manufactured board must have a version. Version advancements are ruled accordingly to *Semantic Versioning*, similarly to what usually happens in software development. To quickly identify the status of each version, I use emojis. The following list explains their meaning: - A *White Heavy Check Mark* (✅) means that it is successfully tested; - A *Negative Squared Cross Mark* (❎) means that it was almost successfully tested (the main functionalities are fine), but there are bugs affecting minor funcionalities; - A *Warning Sign* (⚠) means that the board is not usable out of the box but the bugs are fixable in DIY (decent) fashion; - A *Cross Mark* (❌) means that there are some problems that makes it unusable; - A *White Question Mark Ornament* (❔) means not tested.