BNo055 Sensor CircuitPython Driver GitHub:

https://github.com/adafruit/Adafruit_CircuitPython_BNO055

BNo055 Sensor ReadTheDocs:

https://docs.circuitpython.org/projects/bno055/en/latest/

Nunchuck CircuitPython Driver:

https://github.com/adafruit/Adafruit_CircuitPython_Nunchuk/blob/main/adafruit_nunchuk.py

Nunchuck ReadTheDocs:

https://docs.circuitpython.org/projects/nunchuk/en/latest/api.html#implementation-notes

I've got hundreds of Arduino libraries that we maintain in my 'libraries' folder, and it can very quickly get difficult to maintain them. There's 4 issues I spent an inordinate amount of time on!

First issue is that whenever a library is updated, the IDE does not delete the previous version, but keeps both around...after a few years this ends in a lot of cruft. 

Secondly, libraries downloaded via the IDE are placed into a folder in the format arduino_nnnnn where n is a number, so you don't really know what library is inside it, making the first issue hard to clean up

Thirdly - for Adafruit libraries, they are git clone'd into the library folder which means I sometimes end up in a branch that I'm working on, and then submit a PR. Days later I've forgotten to change back into my main branch, losing out on any merged updates!

Finally - there's constant updates to our libraries, and the IDE does alert me when this happens - which means I need to do a git pull - but in hundreds of libraries this takes a long time to go to each folder and run the git pull command.

THUS a script! This python code does a number of clean up tasks, I only have to run it a few times a week and it will keep my arduino libraries folder nice n tidy. Thanks to ChatGPT4 Sept 25 for the assist, it made the scripting faster (note I did make some changes beyond what GPT4 wrote)

The MAX98357A 3-watt I2S amplifier is wonderful way to output tunes from CircuitPython synthio, but because it produces a balanced Class-D output that only works with speakers, it doesn't interface well with standard unbalanced audio inputs on guitar amplifiers or a workstation's DAW (Digital Audio Workstation). After a couple of somewhat successful attempts to reintegrate the digital speaker signal with special analog amplifiers, it became obvious that what was really needed was an I2S stereo DAC like the discontinued Adafruit UDA1334A DAC (PID#3678).

A search of in-stock and active I2S DAC chips yielded the Texas Instruments PDM510xA family of I2S audio DACs that could meet the overarching project requirements of:

1. Provide an unbalanced ground-centered stereo line-level audio output using a single power supply.
2. A direct pin-for-pin compatible breakout stackable/replacement for the MAX98357A amplifier including shutdown capability (SD).
3. Approximately the same size as the UDA1334A breakout.

The PDM510xA family does not require a master sample clock as the internal phase-locked-loop (PLL) extracts the master clock from the bit clock (BCLK) input. Also, the ground-centered audio output is achieved with an on-chip negative voltage charge pump, eliminating the need for bandwidth-limiting DC blocking capacitors on the DAC output pins.

Assembly of the PCB (YouTube):

Overview

The TV Backlight illuminates the wall behind the TV display to reduce eye strain. The backlight extends the background of the screen image by watching the color near an edge of the display. To reduce distraction, the color and brightness are integrated over time to avoid sudden changes.

The project's CircuitPython code reads the AS7341 spectrometer sensor's eight visible light channels to determine the backlight target color. Using a Euclidean "color distance" comparison, the backlight color is slowly changed to match the target color, within a specified tolerance.

The spectrometer sensor settings are adjusted for relatively low display light levels. The sensor's internal amplifier gain is set to maximum and the integration step and time values are adjusted to maintain a moderately fast conversion rate. Also, rather than just analyzing red, green, and blue components, all eight visible light channels are used to increase the accuracy and resolution of color measurements.

In this configuration, just one of the sensor's channels can reach a count value of near 13k, producing a composite 8-channel resolution that approaches 8x10³² color combinations, much larger than the 17x10⁶ (24-bit) color resolution of the NeoPixel strip. A color count to RGB converter helper reads the three primary color sensor channels, scales the count, and produces an RGB888 (24-bit) color value that's compatible with NeoPixels.

To assist in finding a position near the TV screen for the sensor, the Feather M4's on-board NeoPixel mimics the readings in real-time, albeit at a slightly lower brightness than the illumination strip NeoPixels.

Documents

Test video: https://youtu.be/yFqbalF0FGw

Next Steps

• Build a camouflaged enclosure and vertical mounting wands for the NeoPixel strips.
• Investigate animating the NeoPixel strip color change.
• For home security, enable the NotFlix (Fake TV) code when the TV display is dark for 5 minutes or more.

CircuitPython Code

What had my interest is the combination of price and that it’s a short-throw projector. Typical LCD projectors have a focal distance of 1 meter or more, whereas short-throw varieties…normally quite spendy…focus just a few inches from the front lens, suggesting interesting and creative applications.

See, a few years back we were all agog over the Gakken Worldeye HDMI display — $150 at the time, but now discontinued and “collectible” at $400 — and were looking for economical DIY approaches which never panned out.

Background

Making my annual pilgrimage to all the Halloween stores this year, this “Jabberin’ Jack” animated Jack-o’-lantern caught my attention. It’s a fairly affordable item ($60 or less) with a tiny internal LCD projector and video player to show an animated face:

The Adafruit Controllable Four Outlet Power Relay Module is a very neat piece of hardware (if you live in a 120 volt AC country). It has a pair of contacts on the side that can take a wide range of voltages to switch electrical loads on and off. This is just what my wife wanted, a method to remotely control power outlets to some gear in her office.

But how to switch it remotely. WiFi relies on connectivity that might get hacked over the internet in our view. Bluetooth seems more secure (maybe local hacking is possible, but our locality isn't a concern). I initially picked up an Adafruit Feather ESP32-S3. But CircuitPython Bluetooth doesn't work for UART/Serial profile. I want to, for proof of concept, use the Adafruit Bluefruit LE Connect application (available for iOS and Android) to send codes for on and off. That limits my choices to the Nordic nRF52840-based microcontroller boards.

Code

I modified some example code on how to connect the nRF52840 board to the Connect app. In the Getting Started with CircuitPython and Bluetooth Low Energy guide, I modified the Button Press example to also toggle the button.TX pin high when the up arrow is pressed, low when the down arrow is pressed.

I connected my CPB to my computer with a known good data+power micro B USB cable (Adafruit sells many different ones). I used the Mu editor to copy the example code and modify it to use digitalio for the pin toggling and neopixel to use two of the colorful RGB LEDs as status lights (one for Bluetooth connected, one for the switch state).

I needed to copy several libraries over to the /lib directory on the CIRCUITPY drive with File Explorer on my computer.

• neopixel
• adafruit_ble
• adafruit_bluefruit_connect

The latest Library Bundle is on the circuitpython.org website.

Next I used Mu to save the code to a file named code.py on the CIRCUITPY drive. 

Here is the code:

Unicomp Mini M with CircuitPython

Unicomp is the heir to the IBM Buckling Spring legacy. This style of keyboard has a distinctive sound & feel which some people just can't get enough of. I'm one of them, having used a crusty old Model M for at least a decade at work.

Their "Mini M" is an 87-key ("tenkeyless") layout, and in late summer 2023 the controller was replaced with a board that has a Raspberry Pi Pico soldered on to it.

It's too soon for me to have formed a strong opinion about this keyboard, though I will note that the cable seems to be in the category of "incredibly cursed": It is a USB A-A cable, which should not exist. If your computer is USB-C only you're entering dongle city, but, you're probably used to that.

In this mini-guide, you'll learn how to replace the factory firmware with a fully customizable CircuitPython firmware. Of course, once you have the controller in UF2 bootloader mode, you could also use Arduino or Pico-SDK to program it with the software of your choice.

Note that this involves opening up the keyboard enclosure and there is always the possibility that you will damage the keyboard while doing so.

Reverse Engineering

I don't know who all to credit for the reverse engineering, but all the information I needed was in a fork of the open source keyboard controller "Vial-QMK". Here are the basics:

• Keyboard is organized as a 16x12 matrix, with the columns controlled by a pair of 8-channel muxes. Together, pico pins GP0 through GP4 select one of 16 column channels, with just one of GP3 or GP4 selected by setting to a False pin value
• The 12 row inputs are GP11 through GP22
• The LEDs are on GP6 through 8, with a common anode on GP5 (so set GP5 True always, and GP6 through 8 to False to light the corresponding LED; GP6 is Num Lock)
• The matrix has no diodes, so anti-ghosting must be done in software

A popular gift to new parents is baby board books! Not only are they great for chewing on (good source of fiber), they are also a nice way to introduce early literacy. We also have a 'subscription box of the quarter' which comes with a variety of board books

However, all these books are in English - and if you're trying to expose your lil one to another language it can be challenging to get books in the second language if it isn't a popular one in your country. In this case, we wanted to have some Hebrew language books (the weather-control-machine instruction manual is in Hebrew so it is important for our kiddo to read fluently). We were able to pick up some Hebrew books from the Israel Bookshop - and the library also has some options! But, library books must be returned unchewed and imported books are not inexpensive. We also had lots of gifted books, already... so let's convert them to be bilingual with help from ChatGPT4

Why ChatGPT4?

You don't need to use an LLM to help translate, but my Hebrew is rusty and especially details like getting spelling and nikkud correct is not my highest skill.

Translation is what I like to call an "NP-complete" task - its hard and time-consuming to do right, but you can quickly determine if its done correctly. That makes it a great task to use LLM for: it's a lot faster than copying and pasting text over and over into Google Translate but once its done its quick to verify. It also doesn't innundate you with pop-ups and ads like Morfix .

Requirement: Place an RGB display panel with an attached MatrixPortal in a shadow box.
Problem: The MatrixPortal sticks out.
Solution: Spin it around with a custom OSHPark AfterDark board.

 

The panel connector is a 2-row by 10-pin header (0.1-inch) with the top two and bottom two pins removed. The bottom spacer is M2.5 12mm with a screw added to provide another 1mm depth.

We're close to publicly releasing UART support for Adafruit.io and WipperSnapper. This would enable a device running WipperSnapper to initialize a physically connected UART device, such as the PM2.5 Air Quality Sensor and Breadboard Adapter Kit - PMS5003, and send its data to Adafruit.io. As always with WipperSnapper firmware, this is all performed without requiring a user to write code.

Below is a sneak peek of the following, but how did we get to this result over the course of a month? What went into adding a feature to Adafruit.io and WipperSnapper Firmware? 

Protocol Buffers: How WipperSnapper and Adafruit IO Communicate

When we developed WipperSnapper, we employed Protocol Buffers (Google's open-source data interchange format) to send data between a Device and Adafruit IO.

What are Protocol Buffers? (via protobuf.dev)

Protocol buffers are Google’s language-neutral, platform-neutral, extensible mechanism for serializing structured data – think XML, but smaller, faster, and simpler. You define how you want your data to be structured once, then you can use special generated source code to easily write and read your structured data to and from a variety of data streams and using a variety of languages

The core of this communication revolves around the Adafruit IO website, specifically the component picker form. When you select a UART component on Adafruit.io, it will look something like this:

We live in a breezy area that abuses flags, wind socks, and our patio garden wind chime collection. To keep the collection of wind chimes working, we are always looking for better materials for the annual chime repair ritual.

We recently ditched the UV-resistant nylon fishing line that was usually used for repairs. Despite the UV rating, the nylon line would decay in the sun after a few months. We tried something new (to us) this season; replaced the nylon line with 1/32” stainless steel cable and aluminum crimp ferrules. We're expecting it to stay strong and last a great deal longer.

For lightweight loads such as the hangers for individual chime tubes, the ferrules were sliced in half with a utility knife. The cable was cut to length and ferrules were crimped in place using a ratcheting crimping pliers' 28AWG die. The crimping pliers (Adafruit PID#1213) have a combination die for 28AWG, so only the larger portion of the die was used. Crimping pliers designed specifically for this purpose are available.

Stainless steel cable and ferrules from Amazon

 

An heirloom Harry and David “Pear” 6-note chime from the early 1970s.

(plexiglas sail, striker, and tube spider with brass chain suspension and brass cotter pins; top-hung galvanized steel metric EMT tubes with cable "W" mounts and stainless cable suspension; F#5, G#5, B5, C6, E6, G6 tuning)

 

A CircuitPython Community Bundle color palette and list brightness setter and normalizer tool.

PaletteFader is a CircuitPython helper class for brightness-adjusting color lists and displayio palettes. Normalization is optionally applied to the palette prior to brightness and gamma adjustments. Transparency index values are preserved and associated with the adjusted palette. Creates an adjusted displayio color palette object (displayio.Palette) property that can also be read as a color list.

The Ibanez FL9 Flanger Service Guide was compiled from a collection of original and obsolete information to create a useful guide for maintaining this unique guitar pedal. Credit must be given to the authors of the original 1980s era Service Manual NO. 002 that was used as a template for this updated guide.

November 26, 2022, Cedar Grove Studios

The .pdf version of the guide and detailed repair blog can be downloaded from the project repository:

FL9 New Service Guide (.pdf)

FL9 Detailed Repair Blog (.pdf)

Also available is a KiCAD folder of the as-built PCB design, contained in the project repository:

FL9 PCB Reverse Engineered Design (KiCAD folder)

 

The Idea

I went down a bit of a rabbit hole a week or so ago when thinking about a better way to store all of the dev boards I have for testing. The ideal scenario is to have a lot of surface area to lay them all out so that you can see them all at a glance. No need to dig through anything. One way to do that is with shallow drawers, commonly call flat file storage. I found a flat file cabinet on Craiglist but it was pretty pricey and very large. They are often used for large prints that need to be kept flat. For dev boards, I don't need a lot of area together, just a lot overall.

After seeing creative drawer inserts for the Ikea Kallax bookshelf and some done in cardboard, I realized I could get custom cardboard boxes to fit in each square. I found EcoEnclose which makes custom sized shipping boxes low minimum order ($20) and now have just over 20 boxes for around $40. 10 of the shallowest boxes cost just under $20 and can fit in a single square. (The wood 10 drawer set is $140.)

 

The Details

EcoEnclose has variety of options for the custom boxes: style, strength and inner dimensions. (The use is for going around another box for shipping.)