The Python for Microcontrollers Newsletter is the place for the latest news involving Python on hardware (microcontrollers AND single board computers like Raspberry Pi).
This ad-free, spam-free weekly email is filled with CircuitPython, MicroPython, and Python information that you may have missed, all in one place!
You get a summary of all the software, events, projects, and the latest hardware worldwide once a week, no ads! You can cancel anytime.
It arrives about 11 am Monday (US Eastern time) with all the week’s happenings.
And please tell your friends, colleagues, students, etc.
Hannes (hannesb) posted a working Matter temperature sensor build on the Seeed Studio forum, running on the XIAO nRF54LM20A. He started from the nRF Connect SDK Matter temperature template, added a BME sensor for temperature and humidity readings, and took supply current measurements. The source code is up on GitHub.
SDK 3.4.1 did not produce running code for him. He points at the deprecated Partition Manager as the main obstacle.
A forum reply digs into the static partition file. The app slot was shrunk from 0x125800 to 0x10D800 to fit everything in internal flash, but mcuboot_primary was left at its old size, so the primary and secondary slots overlap. The suggested fix is to move mcuboot_secondary to the board’s on-board 8 MB PY25Q64HA SPI NOR flash. That frees about 768 KB of internal RRAM and allows a symmetric primary slot near 1.8 MB with no DFU decompression at runtime. The reply also suggests raising settings_storage from 48 KB to 64 KB for setups joining more than one Matter fabric, such as Apple Home and Home Assistant at the same time.
The Python for Microcontrollers Newsletter is the place for the latest news involving Python on hardware (microcontrollers AND single board computers like Raspberry Pi).
This ad-free, spam-free weekly email is filled with CircuitPython, MicroPython, and Python information that you may have missed, all in one place!
You get a summary of all the software, events, projects, and the latest hardware worldwide once a week, no ads! You can cancel anytime.
It arrives about 11 am Monday (US Eastern time) with all the week’s happenings.
And please tell your friends, colleagues, students, etc.
This week @adafruit Noe is finalizing his Pepper’s Ghost Monster Eye project while Pedro is testing e-ink displays with Adafruit Marquee. Timelapse this week features a print-in-place one eyed monster.
Turn your bike into a rolling light show with this Persistence of Vision Bike Wheel project from Erin St Blaine.
This build uses six high-speed LED strips mounted across three spokes, with a Feather microcontroller running CircuitPython to draw colorful patterns and images as the wheel spins. A magnetic sensor tracks the wheel speed so the timing can adjust whether you’re cruising slowly or flying down the street.
Load up the included graphics or add your own artwork by saving .bmp or .gif files directly to the Feather. Swap images, logos, symbols, patterns, or whatever else you can fit into 36 pixels of glorious spinning light.
The effect is especially striking in person. Cameras have a notoriously hard time capturing persistence-of-vision displays accurately, but to your eyes the individual LEDs disappear and the artwork seems to float inside the spinning wheel.
It’s a fantastic project for Burning Man bikes, nighttime Critical Mass rides, festivals, parades, or anyone who feels their bicycle could use significantly more LEDs.
From the Guide
Light up your bike for festival season or nighttime Critical Mass rides. Stand out from the crowd with a custom persistence-of-vision bike wheel display, and upload dozens of your own images to create the ride you’ve always dreamed of.
Persistence of vision is the effect that happens when your eyes briefly retain an image after it disappears. By flashing LEDs in carefully timed patterns as the bike wheel spins, those individual points of light appear to blend together into a complete floating image.
This guide shows you how to build a three-spoke, double-sided bike wheel display. There’s some tricky soldering required to get everything wired neatly and securely in place, so this is not a beginner build.
Sample CircuitPython code and images are included, and it’s easy to swap in your own artwork or adapt the layout for your particular wheel and LED setup.
Reddit user jareza shares how they made a working payphone using a Pi Zero.
I just wanted to show off my latest backyard addition to people who will really appreciate it: a fully functional payphone!
I’ve wanted a payphone for ages, but the ones I found for sale were either too expensive (now I know why: payphones are HEAVY) or really beaten up.
On a short trip to Monterrey, Mexico, I found a Facebook ad for a booth and a payphone shell for $30, local pickup only. This payphone was different: it had an extra keypad and a screen. I sent a message and rushed to pick it up.
Now I had a booth and a shell. I could make it shine and look good, but I wanted a real, working phone.
I have ZERO coding experience… but I asked Claude if it could be done, and we basically agreed on “I solder, you code.” That’s exactly what we did.
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Ken Shirriff has published another teardown of Intel’s 8087 floating-point coprocessor on righto.com, this time covering the FPTAN tangent instruction. He removed the chip’s lid with a chisel and imaged the die under a microscope, then read the 1648 micro-instructions in the microcode ROM to work out the algorithm.
The 8087 computes a tangent in 90 microseconds, against 13,000 microseconds for emulation on the 8086. It gets there by combining two methods. First it runs 16 CORDIC steps, an algorithm from 1956 that uses only shifts, adds and table lookups. That leaves a tiny residual angle, which the chip handles with a Padé approximant, the ratio 3x/(3-x2). The error is proportional to x to the fourth, so with x under 2^-16 the result meets the 64-bit accuracy requirement.
FPTAN does not return the tangent. It returns X and Y separately, so the division is left to the programmer. The instruction takes about 450 clock cycles typically. The post walks through the microcode, the implicit exponents used for the fixed-point arithmetic, and the 16-bit shift register that stores the CORDIC decision bits.
