ESP8266 PowerBoard

This expansion board for ESP8266 was specially designed for low power applications.

It has:

• Wake up and power from external trigger or from watchdog
• MicroSD card slot (e.g. for data logging).
• UART, I2C and SPI connectors
• Battery voltage monitor

Power management

Int - the esp8266 is always on and controls the power of periphery (UART, I2C, SD, SPI) by the GPIO5 pin.

Ext - the esp8266 is powered on from external trigger (e.g. from motion detector), and controls the power of itself and periphery by GPIO5 pin.

Sample applications

1. Air condition logger.

The esp8266 wakes up every X seconds (configured), logs the time entry from RTC DS3231 and data from BME280 into the log file on the SD card. If the wifi network is awailable it will send all collected data logs to the Telegram bot (you'll  need to create one).

Source code: https://github.com/xl0e/esp8266_board_logger

The power selector pin should be set to the "Int".

2. Motion detector with notification in Telegram bot.

The HC-SR501 motion detector triggers the power on the esp8266 board which sends the notification to the Telegram bot.

Source code: https://github.com/xl0e/esp8266_board_alarm

The power selector pin should be set to the "Ext".

Uploading firmware

The board doesn't have USB port. So you need an external USB to UART converter (e.g. ch340 or FTDI based).  Warning!!! Please check that converter has 3.3V voltage supply. Most of the converters allow to choose between 5V and 3.3V.

Connect the converter to the board's UART slot (board RX->converter TX, and vice versa).

Set the power selector to the "Ext" position (it will connect the MCU and UART VCC bus).

Before the start of flashing push down the "Flash" button (you can release it after the flashing has been started).