This page assumes that you have installed WipperSnapper on your board and registered it with the WipperSnapper web page. If you have not done this yet, please go back to the previous page in this guide and connect your board.

Blink a LED

One of the first programs you typically write to get used to embedded programming is a sketch that repeatably blinks an LED. IoT projects are wireless so after completing this section, you'll be able to turn on (or off) the LED built into your board from anywhere in the world.

In this demo, we show controlling an LED from Adafruit IO. But the same kind of control can be used for relays, lights, motors, or solenoids.

Navigate to the device page, You should see the board you just connected to Adafruit IO listed on this page.

Verify that your board is online and ready to communicate with Adafruit IO by checking that the device tile says Online in green text.

  • If the board appears offline on the website but was previously connected, press the Reset (RST) button to force the board to reboot.

Once verified that the device is online, click the device tile to navigate to the device's interface page.

Add a new component to your board by clicking the + button or the + New Component button on the device interface.

The Component Picker lists all the available components, sensors, and parts, which can be used with the WipperSnapper firmware. Your board already has a LED built-in, so there's no wiring for you to configure.

Click the LED component

Microcontroller boards contain GPIO pins that can be configured either as an input or an output. The "Create LED Component" screen tells WipperSnapper to configure a general-purpose output pin connected to the LED on your board as a digital output so you can turn the LED on or off.

The PyPortal has a built-in LED located at GPIO #13 (D13 LED). Select this pin as the LED Pin and click Create Component

Behind the scenes, Adafruit IO sends send a command to your board running WipperSnapper telling it to configure the GPIO pin as a digital output. Your board's interface shows the new LED component.

On the device interface, toggle the LED component by clicking the toggle switch. This should turn your board's built-in LED on or off.

Read a Push-Button

You can also configure a board running WipperSnapper to wirelessly read data from standard input buttons, switches, or digital sensors, and send the value to Adafruit IO.

Let's wire up a push button to your board and configure it with Adafruit IO to publish a value to Adafruit IO when the button has been pressed or released. 

In this demo, we show reading the state of a push-button from WipperSnapper. But the same kind of control can be used for reading switches, break beam sensors, and other digital sensors.


We'll be using the board's internal pull-up resistors instead of a physical resistor. 

  • Plug a 3-pin STEMMA to male header pins cable into the D3 connector on the PyPortal.
  • Connect the white wire to one leg of the button.
  • Connect the black wire to the opposite leg of the button.
  • Leave the red wire disconnected.


On the device interface, add a new component to your board by clicking the + button or the + New Component button on the device interface.

From the component picker, select the Push Button.

The next screen presents you with options for configuring the push button. Start by selecting the digital pin you connected to the push button.

The Return Interval dictates how frequently the value of the push-button will be sent from the board to Adafruit IO. For this example, the push-button's value should only be sent when its pressed.

Select On Change 

Finally, check the Specify Pin Pull Direction checkbox and select Pull Up to turn on the board's internal pullup resistor.

Make sure the form's settings look like the following screenshot. Then, click Create Component.

Adafruit IO should send a command to your board (running WipperSnapper), telling it to configure the GPIO pin you selected to behave as a digital input pin and to enable it to pull up the internal resistor. Your board's interface should also show the new push-button component.

Press the button to change the value of the push button component on Adafruit IO.

Read an I2C Sensor

Inter-Integrate Circuit, aka I2C, is a two-wire protocol for connecting sensors and "devices" to a microcontroller. A large number of sensors, including the ones sold by Adafruit, use I2C to communicate. 

Typically, using I2C with a microcontroller involves programming. Adafruit IO lets you configure a microcontroller to read data from an I2C sensor and publish that data to the internet without writing code.

The WipperSnapper firmware supports a number of I2C sensors, viewable in list format here. If you do not see the I2C sensor you're attempting to use with WipperSnapper - we have a guide on adding a component to Adafruit IO WipperSnapper here

The process for adding an I2C component to your board running WipperSnapper is similar to most sensors. For this section, we're using the Adafruit AHT20, an inexpensive sensor that can read ambient temperature and humidity.


First, wire up an AHT20 sensor to your board exactly as follows. Here is an example of the AHT20 wired using I2C with a STEMMA QT cable (no soldering required).

You must swap the jumper next to the I2C connector on the PyPortal from 5V (default) to 3V for the AHT20 to work properly.
  • Use a 4-pin JST PH to JST SH cable.
  • Plug the smaller plug on the cable into the STEMMA QT connector on the AHT20.
  • Plug the larger plug on the cable into the I2C STEMMA connector on the PyPortal.

These steps are necessary for the AHT20 to work with the PyPortal using the I2C connector.

  • Cut the trace indicated by the magenta arrow.
  • Bridge the pads indicated by the green arrow by soldering across both pads.


The second image shows the location of the 5V3 jumper in the context of the board.

If your PyPortal begins repeatedly disconnecting with the AHT20 plugged in, make sure you swapped the 5V/3V jumper on the back of the PyPortal!

Scan I2C Bus

First, ensure that you've correctly wired the AHT20 sensor to your board by performing an I2C scan to detect the I2C device on the bus.

On the upper right-hand corner of the device interface, click Start I2C Scan.

  • If you do not see this button, double-check that your board shows as Online.

You should see a new pop-up showing a list of the I2C addresses detected by an I2C scan. If wired correctly, the AHT20's default I2C address of 0x38 appear in the I2C scan list.

I don't see the I2C sensor's address in the list

First, double-check the connection and/or wiring between the sensor and the board.

Then, reset the board and let it re-connect to Adafruit IO WipperSnapper.

Create the Sensor Component

Now that you know the sensor can be detected by the board, it's time to configure and create the sensor on Adafruit IO.

On the device interface, add a new component to your board by clicking the + button or the + New Component button on the device interface.

The Component Picker lists all the available components, sensors, and parts that can be used with WipperSnapper. 

Under the I2C Components header, click AHT20.

On the component configuration page, the AHT20's I2C sensor address should be listed along with the sensor's settings.

The AHT20 sensor can measure ambient temperature and relative humidity. This page has individual options for reading the temperature and the relative humidity. This comes in handy in the case where you have multiple I2C sensors connected to your board which read the same value. You may choose to enable or disable a specific sensor type on this page.

The Send Every option is specific to each sensor measurements . This option will tell the board how often it should read from the AHT20 sensor 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 both seconds to Every 30 seconds and click Create Component.

The device interface should now show the AHT20 component you created.

After the interval you configured elapses, WipperSnapper automatically reads values from the sensor and sends them to Adafruit IO.

Going Further

Want to learn more about Adafruit IO WipperSnapper? We have more complex projects on the Adafruit Learning System.

Now that you've installed WipperSnapper on your board - let's learn how to use Adafruit IO to interact with your board!

There's a large number of components (physical parts like buttons, switches, sensors, actuators) supported by the WipperSnapper firmware, this page will get you started with the core concepts to build an IoT project with Adafruit IO.

This guide was first published on Feb 26, 2019. It was last updated on 2022-07-27 15:06:07 -0400.

This page (WipperSnapper Usage) was last updated on Aug 12, 2022.

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