Daniel Mangum

@danielmangum.com

827 Followers 272 Following

big fan of computers and human beings.

Lake in Yankton, South Dakota at sunset.
Carriage moving along linear rail driven by belt, which is anchored on a stepper motor shaft and an idler pulley.
Screenshot of linear rail base that also houses the stepper motor, with a rectangular cutout that exposes the side of the motor.
Linear rail with 3D printed carriage attachment and timing belt anchored on 28byj-48 stepper.
Box of machine screws.
Timing belt attachments extruded from the side of the carriage.
A linear rail mounted on the carriage of another linear rail, shown sliding on the X and Y axes.
Bambu A1 Mini working on a small print.
The connector from the previous video, but with the corners cut out so that the majority of it is flush with the Y axis linear rail.
Linear rail mounted on another linear rail to provide xy positioning.
Animation of carriage sliding along linear rail.
CAD model of linear rail shown in video.
150mm linear rail.
Small stepper motor controlled by nRF52840, with button presses changing the motion patterns.
GDS view of nearest neighbor interpolation design.
An extremely small turtle that Lona and I saved from the road and took to the neighborhood creek.
Terminal output reading "This is exactly what I identified earlier. The fix is simple."
Block diagram of the Sony a6000 mirrorless camera.
“JLink JTAG Access on the Pinecil” at number 8 on HackerNews.
In September 2018, Alibaba announced the establishment of a new semiconductor subsidiary company called T-Head which is known as Pingtouge in China.[2][3] It was spun out of Alibaba's research institute DAMO Academy.[3] Pingtouge, which translates to "flat head brother", is the nickname given by Chinese internet users to the honey badger. The name was chosen as honey badgers were said to be brave and smart despite being which represented the spirit the new company aimed for.[2]
“Those 31 digits came at a cost. Building the engines using the technology of the mid 19th century was very expensive. By the time Babbage had abandoned the Difference Engine in 1842 he had been given, and spent, £17,000 by the British government. As a proportion of British GDP scaled up to 2025 values this is around £850 million or roughly a billion dollars!” From: https://thechipletter.substack.com/p/floating-point-the-origin-story
“Simple, Fast, and Practical Non-Blocking and Blocking Concurrent Queue Algorithms” or the “Michael-Scott Queue”
Diagram showing pin mapping from Pinecil breakout board to JLink for JTAG access.
Post on AMD / Xilinx forum: “We’ve heard the feedback from the FPGA and Linux developer community regarding upcoming Vivado licensing changes, particularly concerns around Linux support. Supporting developers across diverse workflows and environments remains important to AMD. To address this feedback, we will continue Linux support in Vivado Basic with the upcoming Vivado 2026.1 release. We appreciate the community’s candid feedback and ongoing engagement as we continue improving the developer experience.”
Slide from talk that reads “What can we do? Stop trying to connect everything to the internet. But how will I get HackerNews karma?”
Pinecil soldering iron connected to a JLink and a Raspberry Pi Pico debugger.
Title slide that reads “Fire RISC: Connecting a RISC-V Soldering Iron to the Internet”.
Accessing Pinecil UART via breakout board and RP2040 running picoprobe.
1.1 Key Concepts The TMC2209 implements advanced features which are exclusive to TRINAMIC products. These features contribute toward greater precision, greater energy efficiency, higher reliability, smoother motion, and cooler operation in many stepper motor applications. StealthChop2™ No-noise, high-precision chopper algorithm for inaudible motion and inaudible standstill of the motor. Allows faster motor acceleration and deceleration than StealthChop™ and extends StealthChop to low stand still motor currents. SpreadCycle™ High-precision cycle-by-cycle current control for highest dynamic movements. MicroPlyer™ Microstep interpolator for obtaining full 256 microstep smoothness with lower resolution step inputs starting from fullstep StallGuard4™ Sensorless homing safes end switches and warns in case of motor overload CoolStep™ Uses StallGuard measurement to adapt the motor current for best efficiency and lowest heat-up of motor and driver In addition to these performance enhancements, TRINAMIC motor drivers offer safeguards to detect and protect against shorted outputs, output open-circuit, overtemperature, and undervoltage conditions for enhancing safety and recovery from equipment malfunctions.
Floating Point Fun on Cortex-M Processors post at number 8 on HackerNews.
Title image showing decompilation of an `addf` function that configures the FPU, then executes a floating point addition.
Examining the contents of the UFSR in GDB (third bit is asserted).
Cover image showing JSON specification for esp-idf hardware accelerated ECDSA PSA driver. Title reads "PSA Crypto: The P is for Portability".
Cover image showing JSON specification for esp-idf hardware accelerated ECDSA PSA driver. Title reads "PSA Crypto: The P is for Portability".
Device classifications by RAM / Flash capabilities with examples.
Coros heart rate monitor.
Victoria Park half marathon results: chip time 1:21:24, gun time 1:21:30.
13 inch framework laptop.
Grafana dashboard showing device metrics.
Front of 3d printed camera lens cap.
Signy, a library for generating signed URLs on embedded devices, at number 12 on HackerNews.
Resistors are easy, capacitors are bit harder, coils are 'magic', but with a bit of practice that magic becomes ritual and ritual should be at least reproducible to the point that the part becomes a manageable quantity.
My recent post "Making Ferrite Core Inductors at Home" at number 6 on HackerNews.
Video of me first applying solder to tip of iron, then using the iron to remove enamel from a copper wire. Extractor is pulling fumes away from the iron.
Image from post showing the ferrite loopstick antennas in the Regency TR-1 and Sony TR-55, two of the earliest AM transistor radios.
Top post on HackerNews entitled “Mobile carriers can get your GPS location”.
Very messy joint with way too much solder.
Side view of perfboard with dual gang variable capacitor soldered on.
Video of me soldering a dual gang variable capacitor to a perfboard.
The top of one of the posts holding up the perf board broken off.
Video of a minimal 3D print with elevated holds for a perf board and ferrite rod.
Dual gang variable capacitor.
Buildings in NYC.
Picture of Central Park covered in snow.
LM386 IC.
An assortment of different sized perf boards.
Oscilloscope recording showing AC sweep from 100 kHz to 1 MHz.
Using two PCBite probes on LC circuit on breadboard.
Oscilloscope screenshot where waveform with 217kHz frequency is decaying.
Ferrite core inductor tank circuit resonant frequency test with Rigol MHO934 oscilloscope.