https://blog.hirnschall.net/ Deep technical articles on FEM simulation, PCB design, signal integrity, (embedded) C++, software engineering, mechanical engineering, FSAE, and applied mathematics by Sebastian Hirnschall. en Wed, 08 Apr 2026 02:58:04 +0000 https://blog.hirnschall.net/gears-for-3d-printing/ https://blog.hirnschall.net/gears-for-3d-printing/ Design circular and non-circular gears for FDM using a circular tooth profile - simpler than involute, uniform teeth regardless of gear outline. Includes PDF. Sun, 30 May 2021 00:00:00 +0000 https://blog.hirnschall.net/gerber-to-step/ https://blog.hirnschall.net/gerber-to-step/ PCB STEP exports omit copper traces - unusable for EM simulation. Convert Gerber files to a simulation-ready STEP with full copper geometry (free tool). Sat, 21 Mar 2026 00:00:00 +0000 https://blog.hirnschall.net/can-transport-layer/ https://blog.hirnschall.net/can-transport-layer/ Eliminate manual bit packing errors in CAN with compile-time validation and code generation. Full C++ implementation with filter and routing safety built in. Sun, 01 Mar 2026 00:00:00 +0000 https://blog.hirnschall.net/perfect-looping-gif/ https://blog.hirnschall.net/perfect-looping-gif/ Random noise typically doesn't loop cleanly. By sampling higher-dimensional noise on a closed path, we can generate nice looping procedural animations. Wed, 03 Mar 2021 00:00:00 +0000 https://blog.hirnschall.net/esp8266-reference/ https://blog.hirnschall.net/esp8266-reference/ Datasheet-accurate pinout for ESP-01, ESP-01S, ESP-07, ESP-12E/F. Covers boot mode pin states, minimal circuits, and rst pin differences per module. Mon, 09 Jan 2023 00:00:00 +0000 https://blog.hirnschall.net/esp8266-eeprom/ https://blog.hirnschall.net/esp8266-eeprom/ Store data across reboots on ESP8266 using EEPROM emulation. Covers read, write, commit, erase, and memory size with Arduino EEPROM library. Mon, 09 Jan 2023 00:00:00 +0000 https://blog.hirnschall.net/auxetic-material/ https://blog.hirnschall.net/auxetic-material/ Auxetic materials expand when stretched. We design a re-entrant structure, simulate it with FEM, and 3D print it in TPU. Sat, 21 Mar 2026 00:00:00 +0000 https://blog.hirnschall.net/perlin-noise/ https://blog.hirnschall.net/perlin-noise/ How Perlin noise generates smooth randomness — gradient noise vs value noise, computational cost, and practical use in terrain generation and animation. Thu, 27 Aug 2020 00:00:00 +0000 https://blog.hirnschall.net/esp8266-webserver/ https://blog.hirnschall.net/esp8266-webserver/ Set up a basic ESP8266 web server using ESP8266WebServer.h — connect to WiFi, respond to URL requests, and read GET parameters. Minimal working code included. Mon, 09 Jan 2023 00:00:00 +0000 https://blog.hirnschall.net/esp8266-pcb-design/ https://blog.hirnschall.net/esp8266-pcb-design/ PCB design rules for ESP8266 based on Espressif's hardware guidelines. Covers antenna placement, keep-out zone dimensions, decoupling, and copper pour strategy. Mon, 09 Jan 2023 00:00:00 +0000 https://blog.hirnschall.net/esp8266/ https://blog.hirnschall.net/esp8266/ Everything you need to add WiFi to Arduino: module comparison, wiring, code examples, power saving, web server, EEPROM, and PCB layout — one reference hub. Sat, 07 Jan 2023 00:00:00 +0000 https://blog.hirnschall.net/maze-generation-js/ https://blog.hirnschall.net/maze-generation-js/ Build a working maze generator in JavaScript using a random walker algorithm. Clean object-oriented structure with full annotated source code included. Sun, 30 May 2021 00:00:00 +0000 https://blog.hirnschall.net/calculating-eigenfrequencies-using-fem/ https://blog.hirnschall.net/calculating-eigenfrequencies-using-fem/ Calculate eigenfrequencies and mode shapes using the Finite Element Method and Rayleigh quotient minimization. Derivation, implementation, and visual results. Sat, 15 May 2021 00:00:00 +0000 https://blog.hirnschall.net/automatic-chop-sticks/ https://blog.hirnschall.net/automatic-chop-sticks/ Build motorized chopsticks with an Arduino servo — fun beginner electronics project with complete parts list, wiring diagram, and step-by-step assembly guide. Sat, 16 Nov 2024 00:00:00 +0000 https://blog.hirnschall.net/everything-aero-concept/ https://blog.hirnschall.net/everything-aero-concept/ Define equation templates, specify your knowns, let a symbolic solver derive the unknowns. Built for Formula Student, applicable to any physics system. Sat, 07 Mar 2026 00:00:00 +0000 https://blog.hirnschall.net/4x-sata-backplane/ https://blog.hirnschall.net/4x-sata-backplane/ Full design walkthrough of a 4-port SATA backplane: impedance matching, crosstalk simulation, S-parameter analysis, and 3D FEM model with printed enclosure. Sun, 29 Mar 2026 00:00:00 +0000 https://blog.hirnschall.net/fem/ https://blog.hirnschall.net/fem/ From computing eigenfrequencies of a tuning fork to full-wave EM simulation of a PCB — practical finite element analysis, applied to real engineering problems. Wed, 05 Apr 2023 00:00:00 +0000 https://blog.hirnschall.net/diy-motorized-slider/ https://blog.hirnschall.net/diy-motorized-slider/ Build a WiFi-controlled motorized DSLR camera slider for under $100. Combines 3D-printed parts with metal rails — full BOM, wiring, and control code included. Tue, 02 Aug 2022 00:00:00 +0000 https://blog.hirnschall.net/diy-useless-box/ https://blog.hirnschall.net/diy-useless-box/ Build a multi-switch useless box with one moving arm, custom PCB and printed mounting. Full Arduino code, STL files, and complete parts list included. Fri, 07 Jan 2022 00:00:00 +0000 https://blog.hirnschall.net/programming-an-advanced-cpp-calculator/ https://blog.hirnschall.net/programming-an-advanced-cpp-calculator/ Build a C++ calculator that parses variables, parentheses, unary operators, and constants. Full recursive descent implementation with walkthrough and source. Wed, 04 Sep 2024 00:00:00 +0000 https://blog.hirnschall.net/esp8266-arduino-ide/ https://blog.hirnschall.net/esp8266-arduino-ide/ Program any ESP8266 module using a spare Arduino as a USB-to-serial adapter. Step-by-step wiring, Arduino IDE board setup, and GPIO0 boot mode procedure. Mon, 09 Jan 2023 00:00:00 +0000 https://blog.hirnschall.net/esp8266-on-battery/ https://blog.hirnschall.net/esp8266-on-battery/ ESP8266 draws ~80 mA active and as little as 20 µA in deep sleep. Full breakdown by mode, GPIO16 wake wiring, and formulas to estimate real battery runtime. Mon, 09 Jan 2023 00:00:00 +0000 https://blog.hirnschall.net/parallel-plate-capacitor/ https://blog.hirnschall.net/parallel-plate-capacitor/ Solve for capacitance, plate area, separation, or permittivity given the other three. Online calculator with formula explanation for each variable. Sat, 23 Nov 2024 00:00:00 +0000 https://blog.hirnschall.net/flow-simulation-js/ https://blog.hirnschall.net/flow-simulation-js/ Simulate particle flow fields in JavaScript using Perlin noise to drive direction. Hands-on object-oriented coding exercise with annotated source code. Fri, 24 Jul 2020 00:00:00 +0000 https://blog.hirnschall.net/esp8266-5v-devices/ https://blog.hirnschall.net/esp8266-5v-devices/ ESP8266 GPIO is 3.3V — connect 5V sensors and Arduinos safely using voltage dividers. Includes circuit diagrams and resistor value calculations. Mon, 09 Jan 2023 00:00:00 +0000 https://blog.hirnschall.net/diy-video-light-stand/ https://blog.hirnschall.net/diy-video-light-stand/ Print a stable, height-adjustable video light stand for standard LED panels — total cost under $4. Print files and assembly instructions included. Sat, 22 Jan 2022 00:00:00 +0000 https://blog.hirnschall.net/diy-smart-window-blinds/ https://blog.hirnschall.net/diy-smart-window-blinds/ Automate window blinds with an ESP8266 for under $10. Includes full schematic, Arduino code, and Homebridge setup for Alexa and Apple HomeKit integration. Fri, 14 Aug 2020 00:00:00 +0000