The Curious Engineer

All blogs / Math

RAW.org

raw.org

Open knowledge across math, software, electronics, robotics, and practical engineering.

MathGraphicsSoftware / engineering practiceElectronics

’10’15’20’25
Posts
307 from 22 Jul 2008 to 30 Oct 2026
Posting
weekly (106 in the last year)
Kind
personal blog
Feed
https://raw.org/feed/

2026 106

  1. Online Spirit Level and Inclinometer
  2. Building a 3D Tunnel Walker from Scratch
  3. Algebra
  4. Algorithms
  5. Differential Calculus
  6. Computer Graphics
  7. Curves and Splines
  8. Kinematics
  9. Vehicle Kinematics
  10. Linear Algebra
  11. Spectral Theory
  12. Vector Operations
  13. Machine Learning
  14. Number Theory
  15. Optimization
  16. Signal Processing
  17. Digital Filters
  18. Stochastics
  19. Algebra
  20. Computer Graphics
  21. Geometry
  22. Circle Geometry
  23. Linear Algebra
  24. Number Theory
  25. Research
  26. Administration
  27. Web Servers
  28. Databases
  29. Mysql
  30. Drivers
  31. Motor Drivers
  32. Games
  33. Canvas Graphics
  34. Graphics
  35. Libraries
  36. Programming
  37. Web Development
  38. Php
  39. Copy an InnoDB Table Between MySQL Servers Without a Dump
  40. Floating Bottle Holder Template Generator
  41. Codebreaker: A Daily Code-Deduction Game
  42. Google Fonts Downloader for Self-Hosting
  43. Extending the Verified Range for \(A!B!=C!\) to \(B \leq 10^{1,000,000,000}\)
  44. Polynomial Square Roots
  45. Rename FT232RL USB Device Online
  46. How It Was Possible to Get Root Access Through MySQL
  47. Milter.js: A Milter Protocol Library for Node.js
  48. Use ChatGPT or Ollama as a Spam Filter for Postfix and Dovecot
  49. TF-IDF Related-Article Ranking with MySQL 8.4
  50. A Simple Quaternion Game Engine
  51. Introduction to Quaternion Derivatives
  52. Introduction to Rotations with Complex Numbers and Quaternions
  53. Calculate the Next Birthday in MySQL
  54. SVG Path Visualizer and Editor
  55. Introduction to CSS 3D Transforms
  56. Introduction to the First Fundamental Form
  57. Approximating Bézier Curves with Circular Arcs
  58. Introduction to Fitting Bézier Curves to Function Graphs
  59. Introduction to the CYK Algorithm
  60. Introduction to Polynomials
  61. Introduction to Stirling's Approximation
  62. Introduction to Algebraic Structures
  63. Introduction to Number Systems
  64. Introduction to Continuity
  65. Introduction to Extrema and the Mean Value Theorem
  66. Introduction to the Gamma Function
  67. Introduction to Integral Calculus
  68. Introduction to Monotone, Bounded Variation, and Convex Functions
  69. Introduction to Real Numbers
  70. Introduction to Rasterization Algorithms
  71. Introduction to Primality Testing
  72. Introduction to Prime Numbers
  73. Introduction to Uniform Random Rotations
  74. Introduction to Uniform Sampling on a Sphere
  75. Cone and Frustum Papercraft Template Generator
  76. Introduction to the Quine-McCluskey Algorithm
  77. Introduction to Exponentiation by Squaring
  78. Fast atan2 Algorithms
  79. Introduction to Limits
  80. Introduction to Natural Numbers and Integers
  81. Introduction to Combinatorics
  82. Introduction to PageRank
  83. Introduction to Spectral Graph Theory
  84. Introduction to EigenGame: PCA as a Nash Equilibrium
  85. Introduction to Principal Component Analysis
  86. Introduction to Singular Value Decomposition
  87. Introduction to Linear Discriminant Analysis
  88. Introduction to LOESS and LOWESS
  89. Introduction to the Gauss-Newton Method
  90. Introduction to the Low-Pass Filter
  91. Introduction to the Moving Average
  92. The square root of two is a loop
  93. Introduction to Bit Manipulation Tricks
  94. Introduction to Bitwise Obfuscation Tricks
  95. Introduction to the Fisher-Yates Shuffle
  96. Introduction to Derivatives
  97. Introduction to Functions
  98. Introduction to Relations
  99. Introduction to Matrices
  100. Introduction to Matrix Inverse
  101. Introduction to Matrix Multiplication
  102. Introduction to Vectors
  103. Introduction to Greatest Common Divisor
  104. Introduction to Modulo and Divisibility
  105. Free 3D Print Files
  106. Intersection.js: 2D Geometry Intersection Library in JavaScript 27 Jun · Robert Eisele

2025 8

  1. Introduction to Binary Search
  2. Introduction to Shopping Cart Kinematics
  3. Introduction to Bloomfilters
  4. raw / Robotics 18 May · Robert Eisele Inverse Kinematics of a 3-DOF Spider Robot Leg This chapter derives an analytical inverse-kinematics solution for a 3-DOF spider robot leg with coxa yaw, femur pitch, and tibia pitch. It decomposes...
  5. Efficient and Accurate Rolling Variance
  6. Introduction to Continued Fractions
  7. CSS Cubic Bézier Editor A professional CSS cubic-bezier timing-function ed... 11 Apr · Robert Eisele
  8. Introduction to Bézier Curves

2024 9

  1. Introduction to Simulated Annealing
  2. Sudoku Solver Online An interactive 9x9 Sudoku solver with a preloaded ... 10 Nov · Robert Eisele
  3. Solving Cubic Equations
  4. Introduction to the Fast Inverse Square Root Algorithm
  5. Introduction to PID Controllers
  6. Introduction to Eigenvalues and Eigenvectors
  7. Introduction to Gradient Descent
  8. CYK Algorithm Visualizer 14 Mar · Robert Eisele
  9. RREF Calculator with Steps 14 Mar · Robert Eisele

2023 3

  1. Introduction to Sets
  2. 04 Introduction to Newton's Method raw / Numerical Analysis
  3. Arc Length of a Function

2022 9

  1. Solving Quadratic Equations
  2. Introduction to Line-Segment and Bézier-Curve Intersections
  3. Introduction to the 3D Cross Product
  4. Quaternion from Two Vectors
  5. Introduction to Quaternions
  6. Introduction to Rational Numbers
  7. Introduction to the 2D Perp Product
  8. Introduction to the Nth Derivative of Sine and Cosine
  9. Introduction to Taylor Series

2021 12

  1. Introduction to Regression
  2. 01 Trackball Rotation using Quaternions raw / graphics · 14 Jul · Robert Eisele
  3. Introduction to Dot Product
  4. Introduction to Series
  5. Introduction to 2D Perp Operator
  6. Introduction to 2D Hit-Testing
  7. GLSL Functions
  8. Introduction to the Bisector of Two Vectors
  9. Introduction to Sequences
  10. Introduction to Lambert W function
  11. Introduction to Power Series
  12. Fast Vector Rotation Using Quaternions A complete derivation of the efficient formula for... 10 Jan · Robert Eisele

2020 1

  1. Introduction to the Average Filter

2019 5

  1. NE555 Astable Circuit Calculator 06 Nov · Robert Eisele
  2. Introduction to Complex Numbers
  3. Introduction to k-Nearest Neighbors
  4. Introduction to Linear Programming
  5. Drawing an Upright Star Polygon 01 Jan · Robert Eisele

2018 5

  1. Introduction to Monte Carlo integration
  2. Introduction to Minimum Spanning Trees
  3. 02 Solving Lights Out Using Linear Algebra raw / Linear Algebra
  4. Circle Through Three Points 18 Feb · Robert Eisele
  5. Introduction to Diffie-Hellman Key Exchange

2017 6

  1. Mathematics of a roller chain animation This article derives the shape traced by a chain, ... 09 Dec · Robert Eisele
  2. Introduction to Gauss-Jordan Elimination
  3. Introduction to Ackermann Steering
  4. Introduction to Wheel Loader Steering
  5. Introduction to Needleman-Wunsch Algorithm
  6. Second Smallest Element in an Array

2016 3

  1. Intersection Area of Two Circles 14 Jul · Robert Eisele
  2. Simplifying and Optimizing Interval Conditions
  3. Introduction to the Log-Sum-Exp Trick in Machine Learning

2011 1

  1. Efficient Pagination in MySQL 24 Oct · Robert Eisele

2010 2

  1. Camera Access in JavaScript 17 Sep · Robert Eisele
  2. Calculating Exact Age Ratios Between Two People

2008 1

  1. Face Detection with PHP and OpenCV A practical PHP workflow for OpenCV cascade-based ... 22 Jul · Robert Eisele

Undated 136

  1. Why 0 999 equals 1
  2. Pagination math
  3. Approximating circles with cubic bezier curves
  4. How to map a square to a circle
  5. Line segment ellipse intersection
  6. Line segment intersection
  7. Partial polyline drawing
  8. Svg arc to gcode
  9. A series paper aspect ratio
  10. Calculate the intersection points of two circles
  11. Intersection point of two lines
  12. Is an angle between two other angles
  13. Reduce the length of a line segment by a certain amount
  14. Rounded corners on path segment
  15. Tangent line to a circle
  16. Extracting translation rotation and scaling from homogeneous transformations
  17. How to plot a covariance error ellipse
  18. Normal vector of a line segment
  19. Plane reflection matrix
  20. Shortest distance between a point and a line segment
  21. Determine if a number is a perfect square
  22. Optimizing integer division
  23. Optimizing integer multiplication
  24. Perfect b ary trees and repunits
  25. Sum of divisors
  26. Calculate the argmin of the sum of absolute values
  27. Make a fair coin from a biased coin
  28. Intraday traffic forecasting
  29. Inverse kinematics of a stewart platform
  30. Add http response headers in lighttpd
  31. Combine css and javascript with lighttpd
  32. Debian lighttpd startup script
  33. Dynamic thumbnail generation on the static server
  34. Enable key repeat on macos
  35. Flashing linux to sdcard
  36. Hiding files on filesystem
  37. Macos internet sharing command line
  38. Postfix dovecot mysql mail server
  39. Face detection with opencv cpp
  40. Php facedetect extension
  41. Age calculation with mysql
  42. Analyze user activity patterns
  43. Avoid n plus one queries with mysql json aggregation
  44. Connect mssql database with python
  45. Field size as power of two
  46. Find friends of friends using mysql
  47. Flag based count using mysql
  48. Import wikipedia into mysql
  49. Indexing text columns in mysql
  50. Inet6 masking with mysql
  51. Model many to many relationships in mysql
  52. Mysql circular buffer
  53. Mysql fulltext location search
  54. Mysql preserve timestamp on update
  55. Mysql query parsing
  56. Mysql sql mode configuration
  57. Mysql wishlist
  58. People near you with mysql
  59. Programmable query layer for mysql
  60. Reliable asynchronous mysql writes
  61. Running standard deviation in mysql
  62. Set and clear bit flags in mysql
  63. Sorted array to mysql
  64. Sql null and three valued logic
  65. Statistical analysis with mysql
  66. Store a tag cloud in mysql
  67. Stream sql to mysql with netcat
  68. Disable vim visual mode on mouse selection
  69. Process json in terminal with jq
  70. A4988 stepper motor driver with arduino
  71. Arduino i2c scanner
  72. Drv8825 stepper motor driver with arduino
  73. Drv8833 motor driver with arduino
  74. Nintendo nunchuk driver
  75. Ph 4502c ph sensor with arduino
  76. Circular sector and arcs with openscad
  77. Css 3d advent calendar
  78. Is a point on the left or right side of a line
  79. Bitset js
  80. Complex js
  81. Dhcp js
  82. Fraction js
  83. Gamecontroller js
  84. Gps js
  85. Jquery borderstyle
  86. Jquery paging
  87. Jquery xcolor
  88. Mod mysql accesslog
  89. Mysql infusion
  90. Php defcon
  91. Php idna
  92. Php infusion
  93. Php sysload
  94. Pnglib js
  95. Polyedge
  96. Quaternion operations in sympy
  97. Read csv into an eigen matrix
  98. Smarty tag cloud plugin
  99. Symbolic gradient with sympy
  100. Excel column width in points with vba
  101. Forcing garbage collection in nodejs
  102. How i got no new de domain
  103. Packing small integers into bit fields
  104. Php 5 3 language fork
  105. Php daemon
  106. Pipe data from node to c
  107. Write a pid file in bash
  108. Create kmz files with php
  109. Faster php behind fastcgi
  110. Minimal gif with php
  111. Parse csv with javascript
  112. Parse csv with php
  113. Board cutting optimizer
  114. Caesar cipher
  115. Compare two lists
  116. Graph editor
  117. Lcd image generator
  118. Linear regression calculator
  119. Modular inverse calculator
  120. Number sequence solver
  121. Password generator
  122. Percentage calculator
  123. Quine mccluskey solver
  124. Regex match extractor
  125. Regex simplifier
  126. Resistor calculator
  127. Roman numerals converter
  128. Running pace
  129. Sla uptime calculator
  130. Sri hash generator
  131. String utility toolkit
  132. Subnet calculator
  133. Triangle calculator
  134. Unit converter
  135. Voltage divider calculator
  136. Wire size calculator