sparkfun ESP8266 Technical document

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ESP8266 Thing Development Board Hookup Guide
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Introduction
The ESP8266 is a cost-effective, and very capable WiFi-enabled microcontroller. Like any microcontroller, it can be programmed to
blink LEDs, trigger relays, monitor sensors, or automate coffee makers, and with an integrated WiFi controller, the ESP8266 is a
one-stop shop for almost any Internet-connected project. To top it all off, the ESP8266 is incredibly easy-to-use: firmware can be
developed in Arduino and uploaded over a simple, serial interface.
To take advantage of all of those benefits, we’ve created the ESP8266 Thing Development Board – an ESP8266 development
board, with an integrated FTDI USB-to-Serial chip.
The ESP8266 Thing Development Board breaks out all of the module’s pins, and the USB-to-serial converter means you don’t need
any peripheral components to program the chip. Just plug in a USB cable, download the Arduino board definitions, and start IoT-ing.
Covered in this Tutorial
This tutorial will help you get your ESP8266 Thing Development Board from zero to Internet-controlled blinking. It’s split into the
following sections:
Hardware Overview – A quick rundown of the Thing Development Board’s components and pinout.
Hardware Setup – Tips and recommendations on what to solder to the Thing Development Board’s I/O pins.
Setting Up Arduino – What truly makes the ESP8266 so powerful is its potential for Arduino-compatibility.
Example Sketch: Web Server – Run an HTTP server on the Thing. Use it to serve web pages, print status messages, and
control LEDs!
Example Sketch: Blink with Blynk – One of our favorite new toys is the Blynk phone app, which allows you to toggle LEDs and
monitor inputs with a simple multi-platform phone app.
Using the ESP8266 in Arduino – A few gotchya’s to look out for when programming the ESP8266 in Arduino.

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Required Materials
Beyond the ESP8266 Thing Development Board itself, all you should need to get started is a micro-B USB Cable, which will deliver
power the board and set up our USB programming interface.
Depending on how you want to use the board, you may also want to add male headers, female headers, or hedge your bets with 10-
pin stackable headers.
Suggested Reading
Before continuing on with this tutorial,
you may want to familiarize yourself
with some of these topics if they’re
unfamiliar to you:
How to Power a Project
Logic Levels
Serial Communication
How to Solder
Hardware Overview
The ESP8266 Thing Development
Board is a relatively simple board. The
pins are broken out to two parallel,
breadboard-compatible rows. The USB
connector sits next to an optional
power supply input, and an ON/OFF
switch – controlling power to the
ESP8266 – sits next to that. And LEDs
towards the inside of the board indicate
power, charge, and status of the IC.

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This section provides a quick overview of the Thing Dev Board’s main components.
Serial and I C Header
The header on the left provides an interface for serial, I C, and power:
Pin
Label
ESP8266 I/O
Function(s)
Notes
GND Ground (0V).
3V3 3.3V
2GPIO2, SDA Can either be used as ESP8266 GPIO2 or I C serial
data (SDA).
14 GPIO14,
SCL, SCLK
Can either be used as ESP8266 GPIO14 or I C serial
clock (SCL).
Also used as the SPI clock (SCLK).
RST The ESP8266's active-low reset input. The board
includes a 10kΩ pull-up resistor on this pin.
2
2
2
2

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TX GPIO7, TX1 ESP8266 UART1 data output.
RX GPIO8, RX1 ESP8266 UART1 data input.
5V USB supply output. If USB is connected, this pin will
supply about 4.8V.
NC Not connected to anything.
GND Ground (0V).
The top portion of this header breaks out the ESP8266’s I C interface, a popular interface for a variety of sensors including motion
sensor, light sensor, digital-to-analog converter, or OLED display, I C is often the protocol of choice.
If you need the extra I/O, instead of I C, the SDA and SCL pins can be used as GPIO 2 and 14 respectively. The SCL pin also
serves as the clock (SCLK) for the ESP8266’s SPI interface.
The lower part of the header breaks out one of the ESP8266’s serial UARTs. This serial port is used to program the thing, so be
careful using it for other tasks.
General I/O Header
The rest of the power, control, and I/O pins are broken out on the other side of the board. They are:
Pin
Label
ESP8266 I/O
Function
Notes
GND Ground (0V).
VIN USB connected: ~5V output
Can alternatively be used as a voltage supply input
to the 3.3V regulator.
5GPIO5 This pin is also tied to the on-board LED.
0GPIO0
4GPIO4
13 GPIO13, MOSI Hardware SPI MOSI
12 GPIO12, MISO Hardware SPI MISO
16 GPIO16, XPD Can be connected to reset to wake the ESP8266
from deep sleep mode.
ADC A0 A 10-bit ADC with a maximum voltage of 1V.
15 GPIO15
External Power Supply
If your project requires a power source other than USB, the Thing Dev Board includes footprints for a 2-pin JST, 2-pin 3.5mm screw
terminal, or a simple 0.1"-pitch 2-pin header.
2
2
2

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You can supply anywhere between 3.3V and 6V into these inputs to power the board.
Note: Unlike the original ESP8266 Thing, the ESP8266 Thing Development Board does not have a built-in LiPo charger. A
LiPo battery can be connected into a populated JST connector, but you'll need to add some extra circuitry to charge it.
Power-Saving Jumpers
A pair of jumpers on the back of the board can be used to help reduce the Thing’s power consumption.
Jumper
Label
Default
Setting
Notes
SLEEP-EN Open Connects GPIO16 (XPD) to the ESP8266's
RST pin.
PWR-LED Closed Completes the power LED indicator circuit.
The SLEEP-EN jumper connects GPIO16 (which has the XPD functionality) to the ESP8266’s reset input. This connection is
required if you want the ESP8266 to automatically wake itself from deep sleep.

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The SLEEP_EN jumper set: enables using and waking up from deep sleep mode, but disables programming.
To use the jumper solder a 2-pin male header and slide a 2-pin jumper on and off. This is a through-hole jumper only,
because you’ll need to remove the jumper to program the ESP2866.
The PWR-LED jumper allows you to disable the power LED. The LED will normally pull about 7mA, which is a ton compared to the
ESP8266’s 10’s of µA consumption in sleep mode.
To disable the power LED, slice the interconnecting trace with your handy hobby knife.
Selecting the Antenna
The Thing Dev Board’s default WiFi antenna is a PCB trace antenna based on this TI app note. It’s cost-effective and actually works
really well!
If you need to connect a more sensitive antenna, or need to route outside an enclosure, a U.FL connector is also available on the
board, but isn’t connected by default to the ESP8266’s antenna pin. To connect this antenna to the chip, you’ll need to swap the
jumper by removing the solder blob and pushing it over to the other side.

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Antenna-select jumper set to U.FL, and an external attached.
Then attach a U.FL WiFi antenna of your choice. Our adhesive antenna or a U.FL-to-RP-SMA adapter/2.4GHz Duck
Antenna combo are good options.
Hardware Setup
To use any of the Thing Dev Board’s GPIO pins, you’ll need to solder something to the board. If you’ve never soldered before, this is
a great time to start! These solder points are easy, through-hole pins, check out our How to Solder - Through-hole Soldering for help
getting started.
What, exactly, you solder to the board depends on how you’ll use it in your project. There are a variety of header options,
including stackable headers, straight male headers, or straight female headers.
Stackable Headers make it convenient to both breadboard the Thing Dev Board and jumper wire out of it.

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And, of course, wire can be soldered to any of the pins that have a long way to connect to something.
Powering the Thing Development Board
The easiest way to power the Thing Dev Board is by connecting a USB cable to the micro-B USB jack. The other end of the USB
cable can be connected to your computer or a USB wall wart. After powering the board, make sure the ON/OFF switch is slid into
the “ON” position, and you should see the “PWR” LED illuminate.
Alternatively, you can solder a variety of connectors into the VIN position to run the board on some other power supply. For example,
you could solder a 2-pin JST connector and mate the board with a 2xAA Battery Holder to power your project.
(A pair of AA batteries may slightly underpower the 3.3V regulator, but the board should still provide more than the 1.8V required for
the ESP8266.)

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COPY CODE
Driver Install: If you've never used an FTDI device, you may need to install drivers on your computer before you can program
the ESP8266. For help with that, follow along with our How to Install FTDI Drivers tutorial.
We have installation directions documented for all major operating systems:
WINDOWS MAC LINUX
Setting Up Arduino
There are a variety of development environments that can be equipped to program the ESP8266. You can go with a simple
Notepad/gcc setup, fine-tune an Eclipse environment, or use a virtual machine provided by Espressif. If you’re just getting started,
though, we recommend the comfy confines of the Arduino IDE.
The amazing ESP8266 community has cooperatively created an ESP8266 addon for the IDE, which is what we'll focus on
using throughout this tutorial. This ESP8266 addon for Arduino is based on the amazing work by Ivan Grokhotkov and the rest
of the ESP8266 community. Check out the ESP8266 Arduino GitHub repository for more information.
Installing the Addon With the Arduino Boards Manager
With the release of Arduino 1.6.4, adding third party boards to the Arduino IDE is easily achieved through the board manager. If
you’re running an older version of Arduino (1.6.3 or earlier), we recommend upgrading now. As always, you can download the latest
version of Arduino from arduino.cc.
To begin, you’ll need to point the Arduino IDE board manager to a custom URL. Open up Arduino, then go to the Preferences
(File > Preferences). Then, towards the bottom of the window, paste this URL into the “Additional Board Manager URLs” text box:
http://arduino.esp8266.com/stable/package_esp8266com_index.json
You can add multiple URLs by clicking the window icon, and pasting in one URL per line.

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Hit OK. Then navigate to the Board Manager by going to Tools > Boards > Boards Manager. Look for esp8266. Click on that
entry, then select Install.
The board definitions and tools for the ESP8266 include a whole new set of gcc, g++, and other reasonably large, compiled binaries,
so it may take a few minutes to download and install (the archived file is ~110MB). Once the installation has completed, an Arduino-
blue “INSTALLED” will appear next to the entry.
Selecting the ESP8266 Thing Board
With the Board addon installed, all that’s left to do is select “SparkFun ESP8266 Thing” from the Tools > Boards menu.

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COPY CODE
Then select your FTDI’s port number under the Tools > Port menu.
Upload Blink
To verify that everything works, try uploading the old standard: Blink. But instead of blinking pin 13, toggle pin 5, which is attached
to the onboard LED.
#define ESP8266_LED 5
void setup()
{
pinMode(ESP8266_LED, OUTPUT);
}
void loop()
{
digitalWrite(ESP8266_LED, HIGH); // LED off
delay(500);
digitalWrite(ESP8266_LED, LOW); // LED on
delay(500);
}
Upload Fails – Troubleshooting

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If every upload attempt results in an error ending with something like error: espcomm_open failed
Try changing the board to Generic ESP8266 Module, and in the sub menus, make sure the following sub-menu's are also set:
Flash Mode: DIO
Flash Frequency: 80MHz
Upload Using: Serial
CPU Frequency: 80MHz
Flash Size: 512K (no SPIFFS)
Reset Method: nodemcu
Faster Uploads! The serial upload speed defaults to 115200 bps, which is reliable, but can feel a bit slow. You can
increase the upload speed by a factor of about 8 by selecting 921600 under the Tools > Upload Speed menu.

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This faster upload speed can be slightly less reliable, but will save you loads of time!
There are still some bugs to be fleshed out of the esptool, sometimes it may take a couple tries to successfully upload a
sketch. If you’re still not having any luck uploading, try turning the board on then off, or unplug then replug the USB cable. If
you still have trouble, get in touch with our amazing tech support team.
Example Sketch: Web Server
The previous example uses the ESP8266 in web client mode. If we instead use the ESP8266 as a web server, you can use a web
browser to control the ESP8266’s LED, or read the status of its GPIO’s.
This section provides two web server examples. The first example sets the ESP8266 up as a WiFi station, connecting to a WiFi
router like the previous example. The other example sets the ESP8266 up as a WiFi access point, so you can use a WiFi-enabled
device to connect directly to the little WiFi chip.
Station (and mDNS) Web Server
To begin, let’s connect the Thing Dev Board back up to the WiFi access point you used in the previous example. Here’s some
example code setting up a web server and pointing a local mDNS domain of “thing.local” to your ESP8266. Make sure you adjust
the values for WiFiSSID and WiFiPSK .
COPY CODE
#include <ESP8266WiFi.h>
#include <ESP8266mDNS.h>
//////////////////////
// WiFi Definitions //
//////////////////////
const char WiFiSSID[] = "WiFiSSID";
const char WiFiPSK[] = "WiFiPSK";
/////////////////////
// Pin Definitions //
/////////////////////
const int LED_PIN = 5; // Thing's onboard, green LED
const int ANALOG_PIN = A0; // The only analog pin on the Thing
const int DIGITAL_PIN = 12; // Digital pin to be read

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After uploading, find a device on the same WiFi network, and point it to one of these locations (the links below will only work if your
device is on the same network):
thing.local/read – Read the status of the ADC and the digital status of pin 12.
thing.local/led/0 – Turn the LED on pin 5 off.
thing.local/led/1 – Turn the LED on pin 5 on.
The ESP8266 should server a web page, even if it’s as simple as ensuring its LED is on.
Access Point (AP) Web Server
Not only can the ESP8266 connect to a WiFi network and interact with the Internet, but it can also set up a network of its own,
allowing other devices to connect directly to it. This example demonstrates how to turn the ESP8266 into an access point (AP), and
serve up web pages to any connected client.
Copy and paste the code from below, or download it here.
After uploading this sketch, find another device that you can connect to a WiFi network – phone, laptop, etc. Look for a network
called “ThingDev-XXXX”, where XXXX is the last 2 bytes of the Thing Development Board’s MAC address.
WiFiServer server(80);
COPY CODE
#include <ESP8266WiFi.h>
//////////////////////
// WiFi Definitions //
//////////////////////
const char WiFiAPPSK[] = "sparkfun";
/////////////////////
// Pin Definitions //
/////////////////////
const int LED_PIN = 5; // Thing's onboard, green LED
const int ANALOG_PIN = A0; // The only analog pin on the Thing
const int DIGITAL_PIN = 12; // Digital pin to be read
WiFiServer server(80);
void setup()
{

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The sketch sets the network’s password to “sparkfun”.
After connecting to your ESP8266’s AP network, load up a browser and point it to 192.168.4.1/read (unfortunately, mDNS doesn’t
work in AP mode). The Thing Dev Board should serve up a web page showing you its ADC and digital pin 12 readings:
After that, give 192.168.4.1/led/0 and 192.168.4.1/led/1 a try.
As always, check through the code comments to get a line-by-line breakdown of what’s going on.
Example Sketch: Blink with Blynk
The previous example is great for showing the nuts-and-bolts behind using HTTP to toggle outputs or read inputs. But if you’re
looking for a much simpler solution, we recommend checking out Blynk.
Blynk is a smartphone application that allows you to easily create “apps” that interact with Internet-connected hardware. It works
with a wide variety of hardware platforms, including the Photon, Raspberry Pi, Arduino/Ethernet Shield, and, of course, the
ESP8266. Here’s a quick how-to on Blynk:
Get the App and Arduino Library
The Blynk app is available for both iOS and Android devices. Click one of the buttons below to get started downloading the app:
BLYNK FOR IOS BLYNK FOR ANDROID
After downloading the app, create an account and log in. Welcome to Blynk!

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You’ll also need to install the Blynk Arduino Library, which helps generate the firmware running on your ESP8266. Download the
latest release from Blynk’s GitHub repo, and follow along with the directions there to install the required libraries.
DOWNLOAD AND INSTALL THE BLYNK ARDUINO LIBRARY
Create a Blynk Project
Next, click the “Create New Project” in the app to create a new Blynk app. Give it any name you please, just make sure the
“Hardware Model” is set to ESP8266.

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The Auth Token is very important – you’ll need to stick it into your ESP8266’s firmware. For now, copy it down or use the “E-mail”
button to send it to yourself.
Add Widgets to the Project
Then you’ll be presented with a blank new project. To open the widget box, click in the project window to open.

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Add a Button, then click on it to change its settings. Buttons can toggle outputs on the ESP8266. Set the button’s output to gp5,
which is tied to an LED on the Thing Dev Board. You may also want to change the action to “Switch.”

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Upload the Blynk Firmware
Now that your Blynk project is set up, open Arduino and navigate to the ESP8266_Standalone example in
the File > Examples > Blynk > BoardsAndShieldsmenu.

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Before uploading, make sure to paste your authoriazation token into the auth[] variable. Also make sure to load your WiFi
network settings into the Blynk.begin(auth, "ssid", "pass") function.
Then upload!
Run the Project
After the app has uploaded, open the serial monitor, setting the baud rate to 9600. Wait for the “Ready (ping: xms).” message.