New ESP8266 DevBoard - CBDB nEXT EVO!

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For any new CBDB orders/requests please feel free to use as usual:
     tech at esp8266-projects.com.

CBDB nEXT Evo bare PCB has also been made available directly at Dirty PCBs, our preferred PCB House for experimenting (**):
 http://dirtypcbs.com/view.php?share=9699&accesskey=91d782fd4a10943fd36ecc371c7ff2cd


(**) - Actually you have there 2 Boards for the price of one, a CBDB nEXT Evo together with a secondary nEXT Extesion Board that brings you a 18Bit ADC (autoscale 0-40V input!), 4x12Bit DAC, Precison Temperature measurement, 8bit I/O port, etc. But more about this one in the next articles. 
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   This simple ESP8266 Board is the result of searching for a smaller and somehow a  more flexibile hardware configuration than the previous CBDB Evolution DevBoard. 
CBDB v2 Evo is perfect for it's Development (like the Battery Monitor System for example) and Educational purposes, you have there all-in-one-board, ADC, DAC, Voltage, Temperature and Current measurement, RTC, LCD Display, buttons, everything. 
 
   BUT sometime you want to keep is as simple as possible. Just a core. A small one. And you don't want a external/separate USB adapter. And you want to be able to extend the Board capabilities easy with other functions, as you wish and when you wish.

If this is the case then maybe the answer can be found below.



Let's see what we need for a simple ESP8266 Board:
- ESP8266 Module 
- USB adapter
- Voltage regulator
- Extension interface


ESP8266 Module 

   Just pick one from your preffered Shop, Ebay, Banggood,Amazon, etc. Ones of the best offers that I find so far (and with modules that were working OK):

 - 5pcs x ESP07 - 14.30
 - 10pcs x ESP12 - 26.99USD

ESP8266 - CBDB nEXT EVO Core

USB adapter

  For USB adapter we will use a CH340G chip. As been in a SOP16 package it is also very easy to solderat home.

CBDB nEXT EVO - USB adapter schematic

Voltage Regulator

Because I want to be able to run the board also from a Li-Ion or Li-Po Battery, for the voltage regulator decided to use something with better specifications than the usual LD1117. 

The choosen one was MCP1825S . I've use it before in many other projects and it's very good LDO: 
-  Input Operating Voltage Range: 2.1V to 6.0V
- 500 mA Output Current Capability
-  Low Dropout Voltage: 210 mV Typical at 500 mA ! - > you have about 1V for LD1117 !
- Low Supply Current: 120 μA

CBDB nEXT EVO - Voltage Regulator

 Extension interface

     The choosen nExtensions Bus Interface that will be used for connecting the ESP8266 Main Board with the other compabile available modules is very simple one, based on the I2C standard interface.  

    In the same time, you have full access to all the pins thru JP1 and JP2 pin headers. You can even use this headers to directly connect the CBDB nEXT Board to a Breadboard as they are at a breadboard friendly distance!


Putting together all the bits and pieces, this is the final result: 

CBDB nEXT EVO 3.4d Schematic

the PCB for it: 
 

CBDB nEXT Evo v3.4d PCB

  and the final result: 

CBDB nEXT Evo v3.4d Board

 
  Next we will continue with Firmware upload and some basic tests.