*Note On Shipping Selection For Customers Outside of the U.S.: If you select the cheaper shipping option the headers are not soldered. This is because when the headers are not soldered we can ship as "Envelope" which costs three times less than a "Package" which is required for soldered headers since the thickness exceeds 1/4". It's more expensive but you'll also get a tracking number. Email us if you have any questions.

What is it?

A board with eight (8) analog to digital (A/D) converters that your ESP8266 can interface with it using I2C. Scroll down and watch the video below to see it in action. We created libraries for Arduino for ESP8266.

Why did you make it?

The ESP8266 is great module, but it lacks some functionality that it's often necessary to use another microcontroller to accomplish what you want. One of the features that it lacks are A/D converters (it only has one and it's hard to access if you have the ESP-01 version).

This board solves this problem by giving your ESP8266 module access to 8 analog to digital converters (analog inputs) via I2C.

What's Included?

• board with 8 A/D converter inputs
• Two (2) seven-pin male - The headers are not soldered if you select the cheap shipping price. This is because with the headers soldered the shipping cost increases to the "Package" category which costs 3 times more and includes tracking.

Note: ESP8266 NOT included.

Software:

We developed some Open Source, easy to use, libraries and examples so you can get started quickly.

• Arduino for ESP8266 Library/SDK and Examples - Yes, you can run Arduino sketches on the ESP8266 alone without an Arduino.
• NodeMCU SDK Module and Examples

Note(s):

• The Arduino for ESP8266 library and examples were tested with Arduino 1.6.5 and the steps listed in the Arduino for ESP8266 repository as of July 24, 2105

• The NodeMCU module and examples were tested with nodemcu_float_0.9.6-dev_20150704.bin.

• Both (Arduino for ESP8266, and NodeMCU) libraries were tested using the schematic in this page, that is: VDD to 3.3V, GND to GND, ESP8266 GPIO0 to SDA, ESP8266 GPIO2 to SCL, and the analog pins (A0-A7) connected to an analog voltage between 0V and 3.3V.

Hardware:

Converter Specs:

• 8 analog inputs for sensors that output 0.0V to 3.3V
• I2C interface
• 10-bit resolution
• Single supply specified operation: 2.7V to 3.6V (VDD). Note: if you use a voltage other than 3.3V to power the board you will have to use the "REF" pin.

Note: If you are going to use this board with an ESP8266 you will need to power it with 3.3V and the analog inputs can only accept 0V to 3.3V.

Pinout:

• VDD - 2.7V to 3.6V (Note: If using with ESP8266 you'll have to use 3.3V for this pin).
• GND - Ground
• SCL - I2C clock (You'll connect this to GPIO0 of the ESP8266)
• SDA - I2C data (You'll connect this to GPIO2 of the ESP8266)
• A0 - Analog input 0 (0v to 3.3V)
• A1 - Analog input 1 (0v to 3.3V)
• A2 - Analog input 2 (0v to 3.3V)
• A3 - Analog input 3 (0v to 3.3V)
• A4 - Analog input 4 (0v to 3.3V)
• A5 - Analog input 5 (0v to 3.3V)
• A6 - Analog input 6 (0v to 3.3V)
• A7 - Analog input 7 (0v to 3.3V)
• A8 - Analog input 8 (0v to 3.3V)

Dimensions

0.74x0.55 inches (18.72x14.07 mm)

FAQs:

• Q1: Can I use two or more boards to have more than 8 analog inputs?

• A1: No. You can only use one board per I2C master because the chip's I2C is factory fixed.

• Q2: Can I connect sensors that put out more than 3.3V? Like 5V for example?

• A2: No. The chip on the board can only read between 0v and VDD where VDD max = 3.6V

• Q3: Why does the board read voltages in pins not connected to anything?

• A3: If you do not connect a pin to anything that pin will be "floating", when a pin is floating it's means it's value is not defined so it can be anything.