The Past, Present, And Future Of CircuitPython

August 1, 2023 by 37 Comments

Modern microcontrollers like the RP2040 and ESP32 are truly a marvels of engineering. For literal pocket change you can get a chip that’s got a multi-core processor running at hundreds of megahertz, plenty of RAM, and more often than not, some form of wireless connectivity. Their capabilities have been nothing short of revolutionary for the DIY crowd — on any given day, you can see projects on these pages which simply wouldn’t have been possible back when the 8-bit Arduino was all most folks had access to.

Limor Fried

Thanks to the increased performance of these MCUs, hackers and makers now even have a choice as to which programming language they want to use. While C is still the language of choice for processor-intensive tasks, for many applications, Python is now a viable option on a wide range of hardware.

This provides a far less intimidating experience for newcomers, not just because the language is more forgiving, but because it does away with the traditional compile-flash-pray workflow. Of course, that doesn’t mean the more experienced MCU wranglers aren’t invited to the party; they might just have to broaden their horizons a bit.

To learn more about this interesting paradigm shift, we invited the fine folks at Adafruit to the Hack Chat so the community could get a chance to ask questions about CircuitPython, their in-house Python variant which today runs on more than 400 devices.

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CircuitPython Happenings Hack Chat With Adafruit

July 24, 2023 by 29 Comments

Join us on Wednesday, July 26 at noon Pacific for the CircuitPython Happenings Hack Chat with The folks from Adafruit!

join-hack-chatIt’s always a party when the good folks from Adafruit stop by the Hack Chat, and we expect no less than that this time around. It’s hard to predict where the conversation will go when [LadyAda], [pt], and [Scott] roll in, but we strongly suspect it’ll center on what’s new in the world of CircuitPython.

We’ve heard that they’ve got some cool stuff going on with CircuitPython on the RP2040, which just might lead to a Python-based fix for the current Bus Pirate supply chain problem. It’ll be a swashbucklingly good time, so make sure you stop by.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, July 26 at 12:00 PM Pacific time. If time zones have you tied up, we have ahandy time zone converter.

Hands-On: BornHack 2020 Badge Has 9×32 Of Bling Fed By CircuitPython

August 27, 2020 by 4 Comments

Despite widespread pandemic cancellations, BornHack still happened this year and they even managed to once again bring an electronic badge to all attendees. If you missed it, I’ve already published an overview of the hacker camp itself. Today let’s dig into the 2020 BornHack badge!

Designed by Thomas Flummer and manufactured in Denmark, it takes the form of a PCB in the shape of a roughly 60 degree circular arc with most of its top side taken up by a 9 by 32 array of SMD LEDs. There is the usual 4-way button array and space for an SAO connector on the rest of the front face, while on the rear are a set of GPIO pads and a pair of AA battery holders for power. Connectivity is via USB-C and infra-red, and usefully there is also a power on/off switch.

At the heart of its hardware is a SAMD21G18A ARM Cortex M0+ microcontroller which is perhaps not the most exciting of chips, but the hardware becomes more interesting with the LED drivers. A pair of the IS31FL3731 chips (you may recognise from Brian Benchoff’s Mr. Robot badge) each drive half of the Charliplexed LED array. These versatile chips take the bother of scanning the LED matrix away from the microcontroller with their own internal frame registers fed from an I2C interface. This choice both makes the best use of the relatively meagre microcontroller in this application, and opens the way for the software choice. This badge runs Adafruit’s CircuitPython, and can thus be programmed over the USB connection in the same way as any other CircuitPython board. To test this I put aside my GNU/Linux laptop, and picked up something considerably less versatile to test its ease of use: a Chromebook.


# configure I2C
i2c = busio.I2C(board.SCL, board.SDA)

# turn on LED drivers
sdb = DigitalInOut(board.SDB)
sdb.direction = Direction.OUTPUT
sdb.value = True

# set up the two LED drivers
display = adafruit_is31fl3731.Matrix(i2c, address=0x74)
display2 = adafruit_is31fl3731.Matrix(i2c, address=0x77)

text_to_show = "BornHack 2020 - make clean"

CircuitPython devices mount as a disk drive in which can be found a Python file that can be edited with the code of your choice. The BornHack badge ships with code to display a BornHack banner text, which serves as a quick introduction to the capabilities of its display. It’s noticeable that the text scrolling performance leaves something to be desired, but this microcontroller is hardly one of the more powerful supported by the CircuitPython platform. The Chromebook was happily able to edit the code, though viewing the Python serial console necessitated diving into its Linux virtual machine.

The BornHack badge then, an attractive design that fulfils the aim of being capable and easy to program through its use of the popular CircuitPython platform, and through its decent sized LED matrix and available GPIOs with the chance of seeing a use beyond the camp as a general purpose display/experimentation platform. It may not be the most powerful of badges, but it does its job well. In particular it has achieved the feat missed by so many others, of arriving at the camp fully assembled and with working hardware and software. You can see more about it in Thomas’ badge presentation at the camp (cut from a stream, talk begins at 5:27) which we’ve placed below the break.

We look forward to seeing its influence upon other similar badges. Meanwhile if you are interested, you can compare it with the 2019 BornHack badge which we reviewed last year.

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CircuitPython Macro Pad Is One Build That Won’t Bite

May 13, 2020 by No comments

Have you built a macro keypad yet? This is one of those projects where the need can materialize after the build is complete, because these things are made of wishes and upsides. A totally customized, fun build that streamlines processes for both work and play? Yes please. The only downside is that you actually have to like, know how to build them.

Suffer no more, because [Andy Warburton] can show you exactly how to put a macro pad together without worrying about wiring up a key switch matrix correctly. [Andy]’s keypad uses the very affordable Seeeduino Xiao, a tiny board that natively runs Arduino code. Since it has a SAMD21 processor, [Andy] chose to run CircuitPython on it instead. And lucky for you, he wrote a separate guide for that.

Practicalities aside, the next best thing about macro keyboards is that they can take nearly any shape or form. Print a case from Thingiverse as [Andy] did, or build it into anything you have lying around that’s sturdy enough to stand up to key presses and won’t slide around on your desk.

No room left on the desk? Build a macro foot stool and put those feet to work.

Via r/circuitpython

The CLUE Tracker Points You To A Target, Using CircuitPython

April 5, 2020 by 2 Comments
The main components are an Adafruit CLUE, Stemma GPS, and a lithium-polymer battery. No soldering required.

[Jay Doscher] shares a quick GPS project he designed and completed over a weekend. The device is called the CLUE Tracker and has simple goals: it shows a user their current location, but also provides a compass heading and distance to a target point. The idea is a little like geocaching, in that a user is pointed to a destination but must find their own way there. There’s a 3D printed enclosure, and as a bonus, there is no soldering required.

The CLUE Tracker uses the Adafruit CLUE board (which is the same size as the BBC micro:bit) and Stemma GPS sensor, with the only other active component being a lithium polymer battery. The software side of the CLUE Tracker uses CircuitPython, and [Jay] has the code and enclosure design available on GitHub.

[Jay] did a nice job of commenting and documenting the code, so this could make a great introductory CircuitPython project. No soldering is required, which makes it a little easier to re-use the parts in other projects later. This helps to offset costs for hackers on a budget.

The fact that a device like this can be an afternoon or weekend project is a testament to the fact that times have never been better for hobbyists when it comes to hardware. CircuitPython is also a fast-growing tool, and projects like this can help make it easy and fun to get started.

Scott Shawcroft Is Programming Game Boys With CircuitPython

March 2, 2020 by 18 Comments

Some people like to do things the hard way. Maybe they drive a manual transmission, or they bust out the wire wrap tool instead of a soldering iron, or they code in assembly to stay close to the machine. Doing things the hard way certainly has its merits, and we are not here to argue about that. Scott Shawcroft — project lead for CircuitPython — on the other hand, makes a great case for doing things the easy way in his talk at the 2019 Hackaday Superconference.

In fact, he proved how easy it is right off the bat. There he stood at the podium, presenting in front of a room full of people, poised at an unfamiliar laptop with only the stock text editor. Yet with a single keystroke and a file save operation, Scott was able make the LEDs on his Adafruit Edge Badge — one of the other pieces of hackable hardware in the Supercon swag bag — go from off to battery-draining bright.

Code + Community

As Scott explains, CircuitPython prides itself on being equal parts code and community. In other words, it’s friendly and inviting all the way around. Developing in CircuitPython is easy because the entire environment — the code, toolchain, and the devices — are all extremely portable. Interacting with sensors and other doodads is easy because of the import and library mechanics Python is known for, both of which are growing within the CircuitPython ecosystem all the time.

CircuitPython is so friendly that it can even talk to old hardware relatively easily without devolving into a generational battle. To demonstrate this point, Scott whipped out an original Nintendo Game Boy and a custom cartridge, which he can use to play fun sounds via the Game Boy’s CPU.

Now You’re Playing With Python

It’s interesting to see the platforms on which Scott has used the power of CircuitPython. The Game Boy brings the hardware for sound and pixel generation along with some logic, but he says it’s the code on the cartridge that does the interesting stuff.

The CPU communicates with carts at a rate of 1MHz. As long as you can keep this rate up and the CPU understands your instructions, you can get it to do anything you want.

Scott’s custom cart has a 120MHz SAMD51. He spends a second explaining how he gets from Python libraries down to the wire that goes to the Game Boy’s brain — basically, the C code underneath CircuitPython accesses direct structs defined within the SAMD to do Direct Memory Access (DMA), which allows for jitter-free communication at 1MHz.

He’s using the chip’s lookup tables to generate a 1MHz signal out of clock, read, and A15 in order to send music-playing instructions to the sound register of the Game Boy’s CPU. It sounds like a lot of work, but CircuitPython helps to smooth over the dirty details, leaving behind a simpler interface.

If you want easy access to hardware no matter how new or nostalgic, the message is clear: snake your way in there with CircuitPython.

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CircuitPython Slithers Into 100th Board — The OHS 2020 Badge

January 21, 2020 by 28 Comments

CircuitPython reached a major milestone last week as it welcomed its 100th board into the fold: the wristwatch form factored badge designed for the 10th annual Open Source Hardware Summit, which takes place March 13th in New York City. Although CircuitPython — an open source derivative of MicroPython — was born at Adafruit, more than half of the boards on this list were produced outside of the company. That just goes to show the strength of the community in support of the snake.

The OSHW 2020 badge joins a litany of familiar boards happy to drop you into a Python interpreter. Among them there’s the Adafruit Feather ecosystem, the ItsyBitsy, specialized boards like the Edge Badge that was in some goodie bags at Supercon, and the CircuitPlayground — that Swiss army knife of sensors which now comes in a Bluetooth version. The first 100 boards were rounded out in strong fashion with [Joey Castillo]’s OpenBook e-reader and the Teensy 4.0. Continue reading “CircuitPython Slithers Into 100th Board — The OHS 2020 Badge” →