Low-cost Lithium Polymer batteries have revolutionized electronics - they're thin, they're light, they can be regulated down to 3.3V and they're easy to charge. On your phone, there's a little image of a battery cell that tells you the percentage of charge - so you know when you absolutely need to plug it in and when you can stay untethered.

The Adafruit LC709203F LiPoly / LiIon Fuel Gauge and Battery Monitor do the same thing. Connect it to your Lipoly or LiIon battery and it will let you know the voltage of the cell, It does the annoying math of decoding the non-linear voltage to get you a good percentage as well!

This guide will explore how to read your device's battery percent, code-free, with Adafruit IO WipperSnapper. It will also explore how to send an SMS alert when the battery is fully charged.

What is WipperSnapper

WipperSnapper is a firmware designed to turn any WiFi-capable board into an Internet-of-Things device without programming a single line of code. WipperSnapper connects to Adafruit IO, a web platform designed (by Adafruit!) to display, respond, and interact with your project's data.

Simply load the WipperSnapper firmware onto your board, add credentials, and plug it into power. Your board will automatically register itself with your Adafruit IO account.

From there, you can add components to your board such as buttons, switches, potentiometers, sensors, and more! Components are dynamically added to hardware, so you can immediately start interacting, logging, and streaming the data your projects produce without writing code.

Parts

First, wire up an LC709203F to your board exactly as follows. Here is an example of the LC709203F wired to an Adafruit ESP32 Feather V2 using I2C with a STEMMA QT cable (no soldering required). You can use a breadboard and wire if you wish, but a STEMMA QT cable makes it much easier.

Assuming you have already gone through the WipperSnapper Setup page and connected your board to WipperSnapper, navigate to the WipperSnapper board list.

On this page, select the WipperSnapper board you just connected.

• If you do not see your board listed - go back to the WipperSnapper Setup Page and make sure it registers with Adafrut.io

Click the New Component button or the + button to bring up the component picker.

Under I2C Components, select the LC709203F.

On the component configuration page, the LC709203F's sensor address should be listed along with the sensor's settings.

The Send Every option is specific to each measurement. This option will tell the Feather how often it should read from each of the LC709203F's two measurements and send the data to Adafruit IO. Measurements can range from every 30 seconds to every 24 hours.

For this example, set the Send Every interval for each sensor to every 30 seconds.

Your device interface should now show the sensor components you created. After the interval you configured elapses, WipperSnapper will automatically read values from the sensor(s) and send them to Adafruit IO.

To view the data that has been logged from the sensor, click on the graph next to the sensor name.

Here you can see the feed history and edit things about the feed such as the name, privacy, webhooks associated with the feed and more. If you want to learn more about how feeds work, check out this page.

The LC709203F has two measurements that each have their own feeds. In this picture, we're looking at the battery cell percent reading, but if you click on the graph icon for the other measurement you'll see its feed history.

First head over to your Adafruit account page. Enter your phone number in the box and click continue and verify.

You should now receive a verification code at the mobile number you entered. Enter this code into the box labeled verification code. Press submit.

You should see a blue box that says Successfully validated phone number and your phone number in the box under mobile number.

If this is all correct you can continue to the next part of the guide.

Fill out the options for this action. Make sure to choose the right feed and set the Limit Every option to a reasonable number so you aren't getting texts every 30 seconds.

We also changed the body so that it would tell us that the battery was fully charged instead of only the percentage.

When the battery is fully charged, you should receive a text message from Adafruit IO!