# Adafruit IO Basics: ESP8266 + Arduino ## Overview ### Adafruit Feather HUZZAH with ESP8266 - Loose Headers [Adafruit Feather HUZZAH with ESP8266 - Loose Headers](https://www.adafruit.com/product/2821) Feather is the new development board from Adafruit, and like its namesake, it is thin, light, and lets you fly! We designed Feather to be a new standard for portable microcontroller cores. This is the  **Adafruit Feather HUZZAH ESP8266**  - our take on an... In Stock [Buy Now](https://www.adafruit.com/product/2821) [Related Guides to the Product](https://learn.adafruit.com/products/2821/guides) ![Angled shot of black, rectangular WiFi development board.](https://cdn-shop.adafruit.com/640x480/2821-07.jpg) The ESP8266 based Feather HUZZAH & the HUZZAH ESP8266 breakout are both very popular options for connecting projects to Adafruit IO. In this guide we are going to walk through the setup needed to get your ESP8266 up and running with the Arduino IDE & Adafruit IO. This same basic setup can be used as you progress through our [Adafruit IO Basics][1] series of guides. Before you continue with this guide, you should consider running through the guides for the ESP8266 Feather or the ESP8266 breakout. We will cover all of the basic setup needed for connecting your ESP8266 to Adafruit IO, but the individual guides go into greater detail about each board. * [Adafruit HUZZAH ESP8266 breakout][3] * [Adafruit Feather HUZZAH ESP8266][4] ## Pros/Cons of the ESP8266 Here are some quick pros & cons if you are considering using the ESP8266 for your Adafruit IO project. #### Pros * Low cost * Great support via the ESP8266 Arduino community * Can be programmed using Lua & Python ([MicroPython][2]), in addition to Arduino * Fast Uploads #### Cons * Power hungry * Limited number of GPIO pins * One analog input pin [1]: https://learn.adafruit.com/series/adafruit-io-basics [2]: https://learn.adafruit.com/building-and-running-micropython-on-the-esp8266 [3]: https://learn.adafruit.com/adafruit-huzzah-esp8266-breakout [4]: https://learn.adafruit.com/adafruit-feather-huzzah-esp8266 Lets get started with assembly. # Adafruit IO Basics: ESP8266 + Arduino ## Assembly We ship Feathers fully tested but without headers attached - this gives you the most flexibility on choosing how to use and configure your Feather # Header Options! Before you go gung-ho on soldering, there's a few options to consider! The first option is soldering in plain male headers, this lets you plug in the Feather into a solderless breadboard ![feather_3010-05.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/192/medium640/feather_3010-05.jpg?1454100293) ![feather_3010-01.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/201/medium640/feather_3010-01.jpg?1454100690) Another option is to go with socket female headers. This won't let you plug the Feather into a breadboard but it will let you attach featherwings very easily A few Feather boards require access to top-side components like buttons or connectors, making stacking impractical. Sometimes you can stack in the opposite order—FeatherWing underneath—or, if _both_ Feather and Wing require top-side access, place the boards side-by-side with a [FeatherWing Doubler](https://www.adafruit.com/product/2890) or [Tripler](https://www.adafruit.com/product/3417). ![feather_2886-01.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/195/medium640/feather_2886-01.jpg?1454100431) ![feather_2886-02.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/196/medium640/feather_2886-02.jpg?1454100477) ![adafruit_products_2890-02.jpg](https://cdn-learn.adafruit.com/assets/assets/000/117/300/medium640/adafruit_products_2890-02.jpg?1672855047) We also  have 'slim' versions of the female headers, that are a little shorter and give a more compact shape ![feather_2940-01.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/197/medium640/feather_2940-01.jpg?1454100533) ![feather_2940-04.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/198/medium640/feather_2940-04.jpg?1454100544) Finally, there's the "Stacking Header" option. This one is sort of the best-of-both-worlds. You get the ability to plug into a solderless breadboard _and_ plug a featherwing on top. But its a little bulky ![feather_2830-01.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/199/medium640/feather_2830-01.jpg?1454100588) ![feather_2830-00.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/200/medium640/feather_2830-00.jpg?1454100660) # Soldering in Plain Headers ## Prepare the header strip: Cut the strip to length if necessary. It will be easier to solder if you insert it into a breadboard - **long pins down** ![feather_headers.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/183/medium640/feather_headers.jpg?1454099573) ## Add the breakout board: Place the breakout board over the pins so that the short pins poke through the breakout pads ## And Solder! Be sure to solder all pins for reliable electrical contact. _(For tips on soldering, be sure to check out our_ [_Guide to Excellent Soldering_](http://learn.adafruit.com/adafruit-guide-excellent-soldering)_)._ ![feather_solder1.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/184/medium640/feather_solder1.jpg?1454099592) ![feather_solder2.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/185/medium640/feather_solder2.jpg?1454099649) ![feather_solder3.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/186/medium640/feather_solder3.jpg?1454099655) Solder the other strip as well. ![feather_solder4.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/187/medium640/feather_solder4.jpg?1454099662) ![feather_solder5.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/188/medium640/feather_solder5.jpg?1454099665) ![feather_solder6.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/189/medium640/feather_solder6.jpg?1454099667) You're done! Check your solder joints visually and continue onto the next steps ![feather_done.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/190/medium640/feather_done.jpg?1454099807) # Soldering on Female Header ## Tape In Place For sockets you'll want to tape them in place so when you flip over the board they don't fall out ![feather_taped.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/203/medium640/feather_taped.jpg?1454101091) ## Flip & Tack Solder After flipping over, solder one or two points on each strip, to 'tack' the header in place ![feather_tack1.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/204/medium640/feather_tack1.jpg?1454101126) ![feather_tack2.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/205/medium640/feather_tack2.jpg?1454101143) ![feather_tack3.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/206/medium640/feather_tack3.jpg?1454101147) ## And Solder! Be sure to solder all pins for reliable electrical contact. _(For tips on soldering, be sure to check out our_ [_Guide to Excellent Soldering_](http://learn.adafruit.com/adafruit-guide-excellent-soldering)_)._ ![feather_soldre1.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/207/medium640/feather_soldre1.jpg?1454101162) ![feather_solder2.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/208/medium640/feather_solder2.jpg?1454101165) ![feather_solder3.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/209/medium640/feather_solder3.jpg?1454101168) You're done! Check your solder joints visually and continue onto the next steps ![feather_soldered.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/210/medium640/feather_soldered.jpg?1454101174) ![feather_done.jpg](https://cdn-learn.adafruit.com/assets/assets/000/030/211/medium640/feather_done.jpg?1454101177) # Adafruit IO Basics: ESP8266 + Arduino ## Using Arduino IDE ![](https://cdn-learn.adafruit.com/assets/assets/000/028/685/medium800/adafruit_products_2821_top_02_ORIG.jpg?1448333324) While the Feather HUZZAH ESP8266 comes pre-programmed with NodeMCU's Lua interpretter, you don't have to use it! Instead, you can use the Arduino IDE which may be more familar. **This will write directly to the firmware, erasing the NodeMCU firmware** , [so if you want to go back to Lua, use the flasher to re-install it](https://github.com/nodemcu/nodemcu-flasher) _[Don't forget to visit esp8266.com for the latest and greatest in ESP8266 news, software and gossip!](http://www.esp8266.com/)_ In order to upload code to the ESP8266 and use the serial console, connect any data-capable micro USB cable to the Feather HUZZAH and the other side to your computer's USB port. Don't forget you will also need to install the SiLabs CP2104 Driver: [Click here to download the CP2104 USB Driver](http://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-drivers) On Mac OS 10.13 and higher, in addition to installing, you will have to give the CP2104 kernel driver permission to load. You can find out if you need to give additional permission by visiting your Security & Privacy settings system preferences screen after installing and looking for the message that says, 'System software from developer "SiLabs" was blocked from loading', like in the picture below. ![](https://cdn-learn.adafruit.com/assets/assets/000/062/133/medium800/adafruit_products_allow-silabs-kernel-driver.png?1537382826) To allow the driver to load, click the lock icon, enter your password, and click "Allow" next to the warning message. After that, you may have to restart your computer before following the steps below and connecting to your Huzzah in the Arduino app. Warning: [Download the CP2104 Legacy USB Driver](http://community.silabs.com/t5/Interface-Knowledge-Base/Legacy-OS-Software-and-Driver-Packages/ta-p/182585) # Install the Arduino IDE 1.6.8 or greater [Download Arduino IDE from Arduino.cc (1.6.8 or greater)](http://www.arduino.cc/en/Main/Software) from Arduino.cc The latest is usually the best ## Install the ESP8266 Board Package Enter ` http://arduino.esp8266.com/stable/package_esp8266com_index.json` into _Additional Board Manager URLs_ field in the Arduino v1.6.4+ preferences. ![](https://cdn-learn.adafruit.com/assets/assets/000/028/673/medium800/adafruit_products_Screen_Shot_2015-07-23_at_12.15.52_PM.png?1448246535) [Visit our guide for how to add ** new boards to the Arduino 1.6.4+ IDE** for more info about adding third party boards](../../../../add-boards-arduino-v164).  Next, use the **Board manager** to install the ESP8266 package. ![](https://cdn-learn.adafruit.com/assets/assets/000/028/674/medium800/adafruit_products_Screen_Shot_2015-07-23_at_12.20.12_PM.png?1448246565) Warning: After the install process, you should see that esp8266 package is marked INSTALLED. Close the Boards Manager window once the install process has completed. ![](https://cdn-learn.adafruit.com/assets/assets/000/035/028/medium800/adafruit_products_adafruit_io_Screen_Shot_2016-08-16_at_11.11.33_AM.png?1471914574) # Setup ESP8266 Support When you've restarted, select **Adafruit Feather HUZZAH ESP8266 ** from the Tools-\>Board dropdown ![](https://cdn-learn.adafruit.com/assets/assets/000/053/351/medium800/adafruit_products_featherhuzzah.png?1524842640) 80 MHz as the CPU frequency ![](https://cdn-learn.adafruit.com/assets/assets/000/032/981/medium800/adafruit_products_80mhz.png?1465933954) You can keep the **Flash Size** at "4M (3M SPIFFS) For **Upload Speed** , select 115200 baud (You can also try faster baud rates, we were able to upload at a blistering 921600 baud but sometimes it fails & you have to retry) ![](https://cdn-learn.adafruit.com/assets/assets/000/032/982/medium800/adafruit_products_baud.png?1465933999) The matching COM port for your FTDI or USB-Serial cable ![](https://cdn-learn.adafruit.com/assets/assets/000/028/678/medium800/adafruit_products_com.png?1448246709) On a mac, you should look for the "SLAB\_USBtoUART" port ![](https://cdn-learn.adafruit.com/assets/assets/000/062/137/medium800/adafruit_products_huzzah-USB-port-arduino.png?1537383052) # Blink Test We'll begin with the simple blink test Enter this into the sketch window (and save since you'll have to) ``` void setup() { pinMode(0, OUTPUT); } void loop() { digitalWrite(0, HIGH); delay(500); digitalWrite(0, LOW); delay(500); } ``` Now you can simply upload! The **Feather HUZZAH** has built in auto-reset that puts it into bootloading mode automagically ![](https://cdn-learn.adafruit.com/assets/assets/000/028/679/medium800/adafruit_products_espblink.png?1448246726) The sketch will start immediately - you'll see the LED blinking. Hooray! # Connecting via WiFi OK once you've got the LED blinking, lets go straight to the fun part, connecting to a webserver. Create a new sketch with this code: ``` /* * Simple HTTP get webclient test */ #include <ESP8266WiFi.h> const char* ssid = "yourssid"; const char* password = "yourpassword"; const char* host = "wifitest.adafruit.com"; void setup() { Serial.begin(115200); delay(100); // We start by connecting to a WiFi network Serial.println(); Serial.println(); Serial.print("Connecting to "); Serial.println(ssid); WiFi.begin(ssid, password); while (WiFi.status() != WL_CONNECTED) { delay(500); Serial.print("."); } Serial.println(""); Serial.println("WiFi connected"); Serial.println("IP address: "); Serial.println(WiFi.localIP()); } int value = 0; void loop() { delay(5000); ++value; Serial.print("connecting to "); Serial.println(host); // Use WiFiClient class to create TCP connections WiFiClient client; const int httpPort = 80; if (!client.connect(host, httpPort)) { Serial.println("connection failed"); return; } // We now create a URI for the request String url = "/testwifi/index.html"; Serial.print("Requesting URL: "); Serial.println(url); // This will send the request to the server client.print(String("GET ") + url + " HTTP/1.1\r\n" + "Host: " + host + "\r\n" + "Connection: close\r\n\r\n"); delay(500); // Read all the lines of the reply from server and print them to Serial while(client.available()){ String line = client.readStringUntil('\r'); Serial.print(line); } Serial.println(); Serial.println("closing connection"); } ``` Dont forget to update `const char* ssid     = "yourssid";` `const char* password = "yourpassword";` to your access point and password, then upload the same way: get into bootload mode, then upload code via IDE ![](https://cdn-learn.adafruit.com/assets/assets/000/028/680/medium800/adafruit_products_wificlient.png?1448246786) Open up the IDE serial console at 115200 baud to see the connection and webpage printout! ![](https://cdn-learn.adafruit.com/assets/assets/000/028/681/medium800/adafruit_products_consoleconnect.png?1448246805) That's it, pretty easy! This page was just to get you started and test out your module. For more information, check out the[ESP8266 port github repository](https://github.com/esp8266/Arduino) for much more up-to-date documentation! # Adafruit IO Basics: ESP8266 + Arduino ## Arduino IO Library ## Install the Required Libraries Now we will need to install the Adafruit IO, Adafruit MQTT, and ArduinoHttpClient libraries using the Arduino **Library Manager**. Navigate to the **Manage Libraries...** option in the **Sketch -> Include Library** menu. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/832/medium800/adafruit_io_library_menu.png?1471361448) Enter **Adafruit IO Arduino** into the search box, and click **Install** on the **Adafruit IO Arduino** library option to install version 3.2.0 or higher. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/834/medium800/adafruit_io_lib_search.png?1471361923) Enter **Adafruit MQTT** into the search box, and click **Install** on the **Adafruit MQTT** library option to install version 1.0.0 or higher. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/835/medium800/adafruit_io_mqtt_install.png?1471362345) Enter **ArduinoHttpClient** into the search box, and click **Install** on the **ArduinoHttpClient** library option to install version 0.2.0 or higher. ![](https://cdn-learn.adafruit.com/assets/assets/000/040/456/medium800/adafruit_io_arduinohttpclient.png?1490653043) # Adafruit IO Basics: ESP8266 + Arduino ## Adafruit IO Setup You are also going to need your Adafruit IO username and secret API key. **[Navigate to your profile](https://io.adafruit.com/) and click the View AIO Key button** to retrieve them. Write them down in a safe place, you'll need them for the next step. ![](https://cdn-learn.adafruit.com/assets/assets/000/074/623/medium800thumb/sensors_weather_3d_printing_adafruit_io_username_and_password.jpg?1555694991) # Adafruit IO Basics: ESP8266 + Arduino ## Example Sketches In the [Adafruit IO Basics][1] series of guides, the examples will be using hardware found in our Adafruit IO starter kit. If you are following along, you might want to consider using the starter kit below. [1]: https://learn.adafruit.com/series/adafruit-io-basics ### Huzzah! Adafruit.io Internet of Things Feather ESP8266 [Huzzah! Adafruit.io Internet of Things Feather ESP8266](https://www.adafruit.com/product/2680) OK you've signed up for [Adafruit.io](http://adafruit.io/) and you're ready to build something cool and Internet-connected. All you need is this starter kit which will get you going with lots of parts that go very well with our service and are the most common sensors and... In Stock [Buy Now](https://www.adafruit.com/product/2680) [Related Guides to the Product](https://learn.adafruit.com/products/2680/guides) ![Top view of kit contents for Huzzah! Adafruit.io Internet of Things Feather ESP8266 - WiFi Starter Kit.](https://cdn-shop.adafruit.com/640x480/2680-01.jpg) ## Example Sketch Setup Now that we have installed all of the dependencies, we can try to run one of the Adafruit IO example sketches. Navigate to the **adafruitio\_00\_publish** sketch by opening the **File -> Examples -> Adafruit IO Arduino** menu. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/838/medium800/adafruit_io_select_example.png?1471364050) Click on the **config.h** tab, and replace the placeholders with your Adafruit IO credentials and WiFi connection info. ![](https://cdn-learn.adafruit.com/assets/assets/000/070/493/medium800/adafruit_io_wifi_creds.png?1549054094) ## Uploading the Sketch Next we will need to select the **Adafruit HUZZAH ESP8266** from the **Tools -> Board** menu. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/839/medium800/adafruit_io_select_board.png?1471364097) Then, select the proper COM port on Windows, or USB device on OS X. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/842/medium800/adafruit_io_port.png?1471365044) Use the arrow icon (➡) to upload the example sketch to the ESP8266. It might take a while, but you should see a **Upload complete.** message at the bottom of the window when the process has finished. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/844/medium800/adafruit_io_upload.png?1471365677) You can now click the serial monitor icon to view the output of the sketch. If everything goes as expected, you should see counter values being sent to Adafruit IO. If not, check your WiFi and Adafruit IO credentials in **config.h** and try uploading your sketch again using the process above. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/845/medium800/adafruit_io_serial_monitor.png?1471365707) Warning: ## Viewing Data on Adafruit IO Now that your ESP8266 is sending data to Adafruit IO, you can view the data stream on [io.adafruit.com][1] by adding a stream block to your dashboard. To do this, click on the + icon on the right hand side of the dashboard. [1]: https://io.adafruit.com ![](https://cdn-learn.adafruit.com/assets/assets/000/034/846/medium800/adafruit_io_add_block.png?1471371714) Add a new **stream block** by selecting it from the modal. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/848/medium800/adafruit_io_new_stream.png?1471371817) Next, choose the **counter** feed from the list, and click the **Next Step** button. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/847/medium800/adafruit_io_choose.png?1471371780) Modifythe stream block options as needed, and click the **create block** button when you are finished. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/849/medium800/adafruit_io_create.png?1471371901) You should now see data flowing into your stream block from your ESP8266. ![](https://cdn-learn.adafruit.com/assets/assets/000/034/840/medium800thumb/adafruit_io_dashboard.jpg?1471364966) ## Next Steps If you would like to continue your educational journey with your ESP8266 & Adafruit IO, check out the [Adafruit IO Basics][1] series of guides. [1]: https://learn.adafruit.com/series/adafruit-io-basics # Adafruit IO Basics: ESP8266 + Arduino ## Adafruit IO FAQ ## Encountering an issue with your Adafruit IO Arduino Project? If you're having an issue compiling, connecting, or troubleshooting your project, check this page first. _Don't see your issue?_  [Post up on the Adafruit IO Forum with your issue](https://forums.adafruit.com/viewforum.php?f=56). ### **I encounter the following error when compiling my sketch:** **`  fatal error: Adafruit_MQTT.h: No such file or directory, `** `#include "Adafruit_MQTT.h"` The Adafruit IO Arduino library is dependent on our Adafruit IO MQTT Library. To resolve this error, from the Arduino IDE, navigate to the **Manage Libraries...** option in the **Sketch -\> Include Library** menu. ![adafruit_io_library_menu.png](https://cdn-learn.adafruit.com/assets/assets/000/065/260/medium640/adafruit_io_library_menu.png?1541529617) To resolve this error, from the Arduino IDE, navigate to the **Manage Libraries...** option in the **Sketch -\> Include Library** menu. ![adafruit_io_mqtt_install.png](https://cdn-learn.adafruit.com/assets/assets/000/065/259/medium640/adafruit_io_mqtt_install.png?1541529632) ### Your board is not connecting to Adafruit IO, but why? Let's find out: **First** , check in `config.h` that you have the correct `IO_USERNAME`, `IO_KEY`, `WIFI_SSID`, and `WIFI_PASS` are set correctly.  **Next** , we're going to modify the while loop which waits for an IO connection in your sketch. Change the line in the status check loop from `Serial.println(.);`to `Serial.println(io.statusText());` `// wait for a connection` `while(io.status() < AIO_CONNECTED) {` `Serial.println(io.statusText());` `delay(500);` `}` Verify and re-upload the sketch. If you're receiving a  **Network disconnected ** error message, the board is not able to talk to the internet. Re-check your hardware, connections, and router settings.  If it's still not showing  **Adafruit IO connected** , check the [IO status on the Adafruit Status page](https://status.adafruit.com/) to make sure the service is online. ### Possibly - you can check [IO status on the Adafruit Status page](https://status.adafruit.com/).  ### There's a [monitor page built-into Adafruit IO](https://io.adafruit.com/monitor) which provides a live view of incoming data and error messages. Keep this page open while you send data to your Adafruit IO devices to monitor data and errors.  ## Featured Products ### Huzzah! Adafruit.io Internet of Things Feather ESP8266 [Huzzah! Adafruit.io Internet of Things Feather ESP8266](https://www.adafruit.com/product/2680) OK you've signed up for [Adafruit.io](http://adafruit.io/) and you're ready to build something cool and Internet-connected. All you need is this starter kit which will get you going with lots of parts that go very well with our service and are the most common sensors and... In Stock [Buy Now](https://www.adafruit.com/product/2680) [Related Guides to the Product](https://learn.adafruit.com/products/2680/guides) ### Adafruit Feather HUZZAH with ESP8266 - Loose Headers [Adafruit Feather HUZZAH with ESP8266 - Loose Headers](https://www.adafruit.com/product/2821) Feather is the new development board from Adafruit, and like its namesake, it is thin, light, and lets you fly! We designed Feather to be a new standard for portable microcontroller cores. This is the  **Adafruit Feather HUZZAH ESP8266**  - our take on an... In Stock [Buy Now](https://www.adafruit.com/product/2821) [Related Guides to the Product](https://learn.adafruit.com/products/2821/guides) ### Adafruit HUZZAH ESP8266 Breakout [Adafruit HUZZAH ESP8266 Breakout](https://www.adafruit.com/product/2471) Add Internet to your next project with an adorable, bite-sized WiFi microcontroller, at a price you like! The ESP8266 processor from Espressif is an 80 MHz microcontroller with a full WiFi front-end (both as client and access point) and TCP/IP stack with DNS support as well. While this chip... In Stock [Buy Now](https://www.adafruit.com/product/2471) [Related Guides to the Product](https://learn.adafruit.com/products/2471/guides) ### Lithium Ion Polymer Battery - 3.7v 2500mAh [Lithium Ion Polymer Battery - 3.7v 2500mAh](https://www.adafruit.com/product/328) Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This battery has a capacity of **2500mAh** for a total of about 10 Wh. If you need a smaller battery, Out of Stock [Buy Now](https://www.adafruit.com/product/328) [Related Guides to the Product](https://learn.adafruit.com/products/328/guides) ## Related Guides - [Adafruit Feather HUZZAH ESP8266](https://learn.adafruit.com/adafruit-feather-huzzah-esp8266.md) - [MicroPython Basics: Loading Modules](https://learn.adafruit.com/micropython-basics-loading-modules.md) - [MicroPython Displays: Drawing Shapes](https://learn.adafruit.com/micropython-displays-drawing-shapes.md) - [Adding Third Party Boards to the Arduino v1.6.4+ IDE](https://learn.adafruit.com/add-boards-arduino-v164.md) - [Adafruit IO Basics: Servo](https://learn.adafruit.com/adafruit-io-basics-servo.md) - [MicroPython Basics: What is MicroPython?](https://learn.adafruit.com/micropython-basics-what-is-micropython.md) - [Fair Weather Friend: Internet-Connected Migraine or Allergies Detector](https://learn.adafruit.com/fair-weather-friend-internet-connected-health-and-leisure-forecaster.md) - [Remote controlled door lock using a fingerprint sensor & Adafruit IO](https://learn.adafruit.com/remote-controlled-door-lock-using-a-fingerprint-sensor-and-adafruit-io.md) - [Adafruit IO Time Tracking Cube](https://learn.adafruit.com/time-tracking-cube.md) - [All the Internet of Things - Episode Three: Services](https://learn.adafruit.com/all-the-internet-of-things-episode-three-services.md) - [MicroPython Smart Holiday Lights](https://learn.adafruit.com/micropython-smart-holiday-lights.md) - [Huzzah Weather Display](https://learn.adafruit.com/huzzah-weather-display.md) - [Building and Running MicroPython on the ESP8266](https://learn.adafruit.com/building-and-running-micropython-on-the-esp8266.md) - [CircuitPython 2FA TOTP Authentication Friend](https://learn.adafruit.com/circuitpython-totp-otp-2fa-authy-authenticator-friend.md) - [Adafruit HUZZAH ESP8266 breakout](https://learn.adafruit.com/adafruit-huzzah-esp8266-breakout.md) - [PyPortal US Election Calendar](https://learn.adafruit.com/pyportal-electioncal-us.md)