Full-featured M.2 interface esp8266 development board: esp-X02-mid

This project welcomes non-profit secondary creations.

1. NGFF(M.2)-B interface, board thickness 0.8mm
2. Try to be compatible with the M.2 protocol so that the development board can be mistakenly inserted into other motherboards with M.2_B-KEY without damaging the development board and the motherboard. Similarly, under normal circumstances, other M.2 devices (such as hard drives) can be inserted into the The motherboard of the development board will not cause damage to the hard drive. However, the author of this development board is not responsible for the economic losses caused by such operations.
3. Onboard PCB antenna to reduce costs. Using ceramic antennas can further reduce the size.
4. This development board leads to almost all the useful pins of esp8266ex, and has both 3v3 input and 5v input. The 3v3 input can be directly used as the power supply of the development board. At the same time, when the development board uses a battery, 3v3 can also be output to the outside; and 5v It can only be used for charging . Since there is no boost module from 3.7v to 5v, it cannot output 5v. Of course, you can replace TP4054 with TP4059, etc. to achieve your goal.
5. This project welcomes non-profit secondary creations. It is worth noting that this module only uses pins 1-34 of M.2 (of which 10-19 are notches), that is, 24 pins, while M. 2 There are 74-10=64 pins in total, and the remaining 40 pins can be used for expansion, such as: iic screen, ink screen, etc. Next, I will try my best to push the module in this direction. Of course, secondary creations are also welcome .
6. There is a WS2812 indicator light on board. There are two short-contact points, which are short-circuit to measure battery voltage and short-circuit to activate Deep Sleep, which are noted in the schematic diagram.
7. Inspired by Forairaaaaa Thanks to the boss for the open source !
8. Since it is a solution verification board, the volume is not controlled to a very small size, which is a pity.