What if you could open a text document on a device, write code, click save, and everything magically starts working? This is the promise of high level programming languages like CircuitPython. Golioth Labs now has an SDK to utilize the language’s fast prototyping capabilities. In addition to Golioth’s cloud functions, it’s super easy to pass data from a networked device up to the Golioth cloud. Click save to stream IoT device data to the cloud!
What is CircuitPython?
Adafruit created CircuitPython (CP), which started as a hardware specific fork of MicroPython (MP). Both CP and MP are based upon the ideas of the Python3 programming language, such as using an interpreter and basing language syntax on whitespace separators. The challenge is that the interpreter must live on a much smaller target than most computers running Python; fitting all of that into 128K of flash and 32K of RAM is a challenge! The hardware specific ports of CP encompass many of the Adafruit boards, but are really targeted around the chipset on those boards. Targets like the Microchip SAMD21 and SAMD51, the Raspberry Pi RP2040, the ESP32-S2, and more. The project continues to grow, both from Adafruit’s ongoing contributions and from a strong community contributing to the project.
Developing for prototyping
One of the strongest features of a language like CP is the ability to quickly iterate code. The “click save and your code starts running” is in contrast to the traditional method of compiling code on an external device (ie. your laptop), downloading it through a debugger (ie. a J-Link), debugging the code, and then watching the output. Because the CP interpreter is on the device itself, it processes the code as the device starts. While this means there is less room for user code, it is a much faster turn around once you click save.
During Golioth “Office Hours” on our community Discord (happening every Wednesday at 1 pm EST / 10 am PST), we had users asking for a faster way to prototype. Golioth developed an SDK in the “Golioth Labs” section of GitHub to interface with the Golioth API(s). This allows users with CircuitPython based programs to connect their IoT devices to the cloud and pass data back to Golioth. Much like the Arduino SDK experiment repo by Golioth Labs, we are interested in trying to extend the functionality of the Golioth cloud to many different platforms. If you have a hardware platform you would like supported, please post about it on our community forum!
Transport? I just want to get there!
As Alvaro points out in the video below, the transport layer is not something the user needs to care about with the Golioth CircuitPython SDK; any time you are working with a Golioth hosted SDK, you will be working at a higher level than the transport layer of communication, such as CoAP or MQTT. Many IoT platforms stop at the transport layer, notably MQTT examples. By moving up to working with APIs to LightDB State or LightDB Stream, you get additional functionality on the device side and you can better maintain your data on the Golioth console. Users always have the option to work at a lower level and peek under the hood at how the communication is happening. For people wanting to get started quickly, it’s important to have a high level way to start streaming data to the cloud.
Getting started with CircuitPython and Golioth
In the demo below, Alvaro showcases a sample setup using the following
- CircuitPython hardware binaries
- This can be any of the listed supported hardware on the Downloads page
- Alvaro shows this on a Sparkfun nRF52840 MicroMod and carrier board
- The Adafruit CircuitPython Community Bundle Libraries
- The Golioth CircuitPython SDK
- The mu IDE
- An external ESP32-C3 running in ESP-AT Mode
First follow the Getting Started Guide to program your chosen hardware with the .UF2 file that represents the underlying CP tools, such as the interpreter and the code required to make your specific microcontroller into a CircuitPython based device.
The next step is hooking up the MicroMod device to the ESP32 modem using jumper wires. Read your board documentation to find an accessible UART port (TX/RX). Once completed, this enables the (Bluetooth based) nRF52840 to communicate over a UART connection to the modem and gain a connection to the internet using the ESP32’s WiFi interface. Credentials for the WiFi modem to connect to a local hotspot are sent from the nRF52840 to the ESP32 using AT Commands early in the CircuitPython program.
The example code on the Golioth CircuitPython SDK primarily lives in code.py. The device first connects using credentials for the WiFi network and PSK information for validating onto the Golioth cloud contained within secrets.py. After the UART is configured, the main processor (nRF52840 in the example below) starts communicating with the modem. In Alvaro’s example, he is sending the internal temperature of the processor using LightDB stream. He is able to send an update down to the board using LightDB State to remotely turn on an LED on the board, which is listening for changes on the /led path, similar to other examples that use LightDB State.
Watch the demo
It all comes together in the video below. Learn about how Golioth and CircuitPython pair to make a great combination for prototyping your next sensor project.
