We compare the two operating principles behind the rotary encoder — optical, which reads position by interrupting light, and magnetic, which reads the direction of a magnetic field — from a motor's shaft angle and speed sensor. From the encoder industry's surprising origin at an organ maker, to the newbot project's real measurement of a 1.2m straight-line run being misread as an 80° turn when the actual rotation was 6.5°, we trace the real story of the encoder that underpins — and sometimes betrays — wheel odometry accuracy.
September 3, 2026 Sensors & HardwareWe compare the actuators that serve as a robot's "muscles" across three angles — the BLDC motor, the stepper motor, and the servo motor. These three aren't actually a parallel classification; motor construction (BLDC/stepper) and control architecture (servo) are two different axes that get conflated. Untangling that confusion, we trace the real torque/response/control tradeoffs from NASA's brush-wear-in-vacuum problem to the birth of Wiener's cybernetics.
September 2, 2026 Sensors & HardwareWhat determines a robot's or drone's range and safety isn't the motor or the sensor suite — it's the battery and its BMS (Battery Management System). From the electrochemistry of lithium-ion cells to cell balancing and protection circuits, we compare real specs from Molicel's high-discharge cells, DJI's intelligent flight batteries, and Samsung SDI's push into next-generation solid-state batteries — and look at what the Boeing 787 fire taught the industry about the limits of a BMS.
September 2, 2026 Sensors & HardwareForce sensors give a robot arm its 'sense of the arm,' and tactile sensors give a robot hand its 'sense of the fingertips.' We trace the physics from strain gauges through three tactile-sensing approaches — piezoresistive, capacitive, and optical — and survey real products from ATI, Bota Systems, and XELA Robotics to Shadow Robot's prosthetic-style hand carrying 129 sensors, alongside the true story of the strain gauge's simultaneous invention in 1938.
September 2, 2026 Sensors & HardwareWe compare the embedded computers that serve as a robot's "brain" across three design philosophies — the general-purpose SoC of the Raspberry Pi 5, the GPU-integrated AI computer of NVIDIA Jetson Orin, and the dedicated ASIC of Google Coral. From what the TOPS/W efficiency metric actually means, to why the newbot project chose a general-purpose SoC, to the real 2026 story of an AI-datacenter DRAM crunch hitting the hobbyist SBC market.
August 28, 2026 Sensors & HardwareAn ultrasonic sensor measures a nearby obstacle's distance from the round-trip time of an ultrasonic pulse — the acoustic counterpart to LiDAR. It can see straight through what trips up optical sensors, transparent glass and black objects included, but its effective range tops out at a few meters. We work through bat-echolocation research, sonar's development in the First World War, the Bosch USS Gen 6's measured range, the Murata MA40S4S and MaxBotix modules that are staples of robotics, and the real-world example of Toyota's eight-sensor Intelligent Clearance Sonar — and how each of these changes what performance you actually get.
August 22, 2026 Sensors & HardwareMillimeter-wave radar measures distance and relative velocity from the reflection of radio waves, making it the sensor most resistant to rain, fog, glare, and other adverse conditions that give optical sensors trouble. We work through how FMCW's beat frequency yields distance and velocity simultaneously, radar's technology lineage running back to Chain Home in the Second World War, Tesla's abandonment and later reinstatement of radar, the 4D imaging specs of the Continental ARS540, and the real-world example of Honda SENSING 360's five-radar 360-degree coverage — and how each of these changes the range/field-of-view/resolution trade-off.
August 16, 2026 Sensors & HardwareRTK combines satellite positioning with correction data from a base station, shrinking the several-meter error of standalone GNSS positioning down to centimeter level. We work through how dual-frequency positioning cancels ionospheric delay, how u-blox's ZED-F9P drove low-cost RTK into the mainstream, Trimble RTX and Japan's own Michibiki (QZSS), and the real-world example of Kubota's nationwide network of 342 RTK base stations for farm machinery — and how each of these changes what positioning accuracy you actually get.
August 10, 2026 Sensors & HardwareAn IMU pairs an accelerometer with a gyroscope to directly sense a vehicle's own translational acceleration and rotational rate. Unlike cameras or LiDAR, it depends on nothing external — but that self-containment comes with an inescapable fate: error accumulates over time (drift). We work through the MEMS gyroscope principle, Allan-variance noise analysis, the grading scale from consumer chips to navigation-grade modules, and Xsens's MTi series product strategy.
August 4, 2026 Sensors & HardwareActive stereo projects a pattern with an infrared emitter and does stereo matching; structured light reads depth from how a known pattern distorts; time-of-flight reads distance directly from a phase shift — three coexisting approaches to depth cameras. We look at the principles behind each and real examples from the Intel RealSense D435i, Microsoft Kinect, Orbbec Femto Bolt, and iPhone TrueDepth, and trace how Israeli startup PrimeSense's technology gave birth to Kinect, got acquired by Apple, and was reborn as Face ID.
July 29, 2026 Sensors & HardwareA stereo camera triangulates distance from the disparity between two lenses, solving the absolute-scale problem that fundamentally limits monocular cameras. We look at real specs from the Stereolabs ZED 2i, Luxonis OAK-D, and e-con Systems TARA, and trace the baseline-length tradeoff through the evolution of Subaru's EyeSight, which has shipped on over 5 million vehicles since 2008 — plus the story of how EyeSight's creator left Subaru to found his own stereo-vision startup.
July 23, 2026 Sensors & HardwareA monocular camera reads lane lines, signs, and obstacles through a single lens, gaining low cost and a small footprint at the price of a fundamental limitation — a single image alone cannot fix absolute distance. We look at real examples from Mobileye EyeQ6L, Tesla HW4, Continental MFC500, and comma.ai to see how each works around that constraint, and trace how a Hebrew University lab became Mobileye and was acquired by Intel for over $15 billion, plus Tesla's 2021 decision to "delete" radar from Tesla Vision.
July 19, 2026 Sensors & HardwareLiDAR measures distance from the round-trip time of light, from the rotating Velodyne Puck to the non-rotating Livox Mid-360S that drove costs down, to the Chinese players Hesai and RoboSense. We compare real specs from actual products in production — and trace the industry's real backstory, from the DARPA Grand Challenge to the DJI spinoff to the collapse of Volvo's deal with Luminar.