Using a Notecarrier-AF? The AF is no longer available for purchase, but we still support it. You can complete the Notecarrier-F version of this tutorial with that board.
Don't see your favorite hardware here? Rest assured the Notecard works with virtually every MCU and SBC available. If you can't figure out how to complete this tutorial let us know in our forum and we can help you out.
This tutorial should take approximately 40-50 minutes to complete.
In this tutorial, you'll learn how to take sensor readings from a Device and send readings to your Notecard and the Blues Wireless Notehub. You'll use CircuitPython running on a Adafruit Feather M4 Express wired up to Notecarrier-F hardware. If you would like to use a different language, board, or Notecarrier, modify the dropdowns at the top of this guide.
The tutorial uses mock sensor readings for simplicity, but feel free to hook up a physical sensor of your choice and use that instead.
If you get stuck at any point during this tutorial, the full source for each example is available on GitHub:
First, you’ll need to get all of your hardware connected. Follow the instructions below to connect your Adafruit Feather M4 Express and Notecard mounted on a Notecarrier-F.
In order to complete this guide, you’ll need the following:
- Notecard mounted to Notecarrier-F.
Any CircuitPython-capable Microcontroller (MCU) with Feather headers. We'll be using the Adafruit Feather M4 Express, but any MCU with a CircuitPython bootloader and binary will do. Be sure to follow the instructions for burning the bootloader and flashing the CircuitPython binary to your device. And if you're using the Adafruit Feather M4 Express, make sure you update your board to the lastest version of CircuitPython.
A text editor or IDE that works well with CircuitPython, like Mu or Visual Studio Code.
- Micro USB to USB-A cable.
Plug your Feather-compatible Adafruit Feather M4 Express device into the Feather headers on the Notecarrier-F.
Attach your microcontroller to your computer with a Micro USB to USB-A cable, using the Micro USB port on the microcontroller.
Now that your hardware is all connected, let’s create a new Notehub project to receive sensor readings from your Notecard.
Navigate to notehub.io and log-in, or create a new account.
Using the New Project card, give your project a name and ProductUID.
NOTE: The ProductUID must be globally unique, so we recommend a namespaced name like
"com.your-company.your-name:your_product"
.
Take note of your ProductUID. This identifier is used by Notehub to associate your Notecard to your project.
Now you're ready to write some firmware. When communicating with the Notecard,
you can manually send requests using the Serial write
function and passing-in
JSON objects, or use the note-python library. The code snippets below show both,
so feel free to use the approach that works for you.
The rest of this tutorial assumes you have already burned the bootloader and flashed the CircuitPython binary to your MCU.
If you haven't, please consult Adafruit's guide for Installing CircuitPython.
Install the Notecard Python Library
To use the
note-python
library, you'll first need to download or clone it from the GitHub repo.Unzip the archive and copy the
notecard
directory into thelib
directory of yourCIRCUITPY
mount.Add an
import
for the library at the top of yourcode.py
file.import notecard
Set up Your Notecard
Add some additional imports to the top of your
code.py
file:import board import busio import time import json
Add a definition for your ProductUID using the value you specified when creating your Notehub project.
productUID = "com.your-company.your-name:your_product"
Configure the I2C Bus and connection to your Notecard, and initialize the connection to the Notecard using the
OpenI2C
function. Be sure to set thedebug
parameter toTrue
to see Notecard requests and responses.port = busio.I2C(board.SCL, board.SDA) card = notecard.OpenI2C(port, 0, 0, debug = True)
Now, we'll configure the Notecard. Using the
hub.set
request, we associate this Notecard with the ProductUID of your project and set the Notecard to operate incontinuous
mode, which indicates that the device should immediately make a connection to Notehub and keep it active.req = {"req": "hub.set"} req["product"] = productUID req["mode"] = "continuous" rsp = card.Transaction(req)
The lines above build-up a JSON object by adding two string values for product and mode, and then fires the request off to the Notecard with the
Transaction
function.Save the
code.py
file to flash this code to your device.Using your IDE or tool of choice, open a Serial monitor to your CircuitPython device. If everything has been connected and configured properly, you'll see a few debug messages, including the JSON object you sent, as well as the response from the Notecard
{}
.
If you have your own sensor, feel free to hook it up and use your own values instead of this tutorial's mocked ones.
Now that you've configured your MCU to communicate with the Notecard, let's grab some pseudo sensor readings.
To generate psuedo sensor readings you'll use the
notecard-pseudo-sensor
library. Start by downloading or cloning the library from its GitHub repo.Next, unzip the archive and copy the
notecard_pseudo_library
directory into thelib
directory of theCIRCUITPY
mount.Add an import for the library at the top of your
code.py
file.import notecard_pseudo_sensor
Configure the pseudo sensor with a reference to the Notecard you created earlier.
sensor = notecard_pseudo_sensor.NotecardPseudoSensor(card)
Add the following code block to the bottom of your
code.py
file. This takes a mock temperature and humidity reading before sleeping for 15 seconds and repeating the process.while True: temp = sensor.temp() humidity = sensor.humidity() print("\nTemperature: %0.1f C" % temp) print("Humidity: %0.1f %%" % humidity) time.sleep(15)
Save
code.py
and reopen the Serial monitor. Every 15 seconds, you'll see new readings.
Now that we're getting sensor readings, let's send these to our Notecard.
To send a sensor reading to the Notecard, we'll need to construct a new JSON request to the
note.add
API that includes a new Notefile name (sensors.qo
), sets thesync
field to true to instruct the Notecard to sync to Notehub immediately, and finally, sets thebody
to the sensor temperature and humidity. Add the following inwhile
loop right after theprint
commands to print out readings.req = {"req": "note.add"} req["file"] = "sensors.qo" req["sync"] = True req["body"] = { "temp": temp, "humidity": humidity} rsp = card.Transaction(req) print(rsp)
Save this code to your device. After restart, the Serial monitor will update to display the response from the
note.add
request (the total number of Notes in the notefile) each time you add a new reading.
Once you start capturing readings, your Notecard will initiate a connection to Notehub and will start transferring Notes. Depending on signal strength and coverage in your area, it may take a few minutes for your Notecard to connect to Notehub and transfer data.
Return to notehub.io and open your project. You should see your notecard in the Devices view.
Now, click on the Events left menu item. Once your sensor Notes start syncing, they’ll show up here.
You’ve successfully connected your Adafruit Feather M4 Express and sensor to your Notecard!
Now you're ready to connect this Notecard project to a cloud application! Take a look at our routing tutorials, which cover a number of popular cloud applications and data visualization tools.
During this tutorial, you set your Notecard into continuous
mode, which
maintains an active network connection and enables faster syncs with Notehub.
It doesn't have much impact on data usage, but it will draw more power. If
you're connected to battery power, or want to transition your project to battery
power, then you can put your Notecard into periodic
mode with the following
request using the in-browser terminal or directly in your firmware.
{
"req": "hub.set",
"mode": "periodic",
"outbound": 60,
"inbound": 120
}