For an ESP8266, with programming connectors and switches and supporting Deep Sleep mode. Designed to connect to a BME280 Temp/Humidity/Barometer by wire using I2C.

BOM

• C1 1uF 1206 SMD
• C2 10uF 1206 SMD
• P1 JST XH B04B 4 Pin Straight
• P2 2 Pin Header Straight
• P3 6 Pin Header Straight
• P4 JST XH B02B 2 Pin Straight
• R1 0R 1206 SMD 1%
• R2 4.7K 1206 SMD 1%
• R3 4.7K 1206 SMD 1%
• R6 4.7K 1206 SMD 1%
• SW1 ALPS SKQGAFE010 SMD Tactile NO
• SW2 ALPS SKQGAFE010 SMD Tactile NO
• U1 ESP-12F
• U2 MCP1700T-3302E/TT SOT-23

The board design has been updated since this version:

• I missed off a pull up resistor on CH_PD (but can easily be tacked on the back of the board if you use this version)
• redesigned the layout so my fingers could get at the switches ;-)
• Added a switch to bypass the regulator so the circuit could be used either with 3.2v LifePO4, or 3.7v Li-ion batteries

All updates on my github repo here: https://github.com/theopensourcerer/esp8266_envmonitor