The Amp Hour

Dave and Chris catch up on Dave’s visit to the University of Sydney Open Day, the shift toward practical hands-on engineering education, and open-source robotics like the Seeed Studio SO-101 and Hugging Face Micro Duck. They also discuss calculator forensics, Dave mentoring his intern Dylan through voltage regulator selection, AI-assisted PCB layout tools, why Chris wants to be “the Walmart greeter of electronics,” reverse-engineering the Rigol DNA800 network analyzer, Dave’s classic toaster design story, and news from Espressif and Build Australia. Timeline Open Day at Sydney Uni: Dave discusses taking his son Sagan to the University of Sydney Open Day and wondering where all of their engineering graduates end up working. (00:00:45) Where Do Sydney Uni EE Grads Go?: They speculate on why University of Sydney graduates rarely show up in practical engineering job applicant pools, noting high international student enrollment and potential moves into fintech or graduate school. (00:02:30) Practical Engineering Education: Dave expresses surprise at the massive emphasis on practical, first-year hands-on projects across all engineering disciplines at Sydney Uni compared to past decades. (00:05:15) US vs. Australian Engineering Schools: Chris and Dave compare recruitment dynamics, big state universities like Michigan and UIUC, and smaller elite institutions like Rose-Hulman, Olin, and Harvey Mudd. (00:07:30) Larry Sears and Campus Makerspaces: Chris remembers past guest Larry Sears and his donation to build the 50,000 sq. ft. Sears think[box] makerspace at Case Western Reserve, comparing it to institutional makerspaces at Georgia Tech and Duke. (00:10:15) School Calendars & High School STEM: A quick look at Australian vs. US academic calendars and the rise of high school robotics programs like FIRST Robotics and Lego competitions. (00:13:45) Seeed Studio SO-101 Robot Arm: Chris shares his excitement about assembling the open-source SO-101 robot arm kit from Seeed Studio for trade show demos, using leader-follower training and Vision-Language-Action (VLA) models. (00:15:30) Hugging Face & Micro Duck Robot: They talk about Nvidia’s acquisition memes ($12.96B ASCII easter egg decoding to the hugging face emoji) and Pollen Robotics / Hugging Face’s upcoming $400 open-source Micro Duck robot kit. (00:17:45) Calculator Forensics: Dave describes explaining 4-bit processors and datamath.org Calculator Forensics to his son Huxley, testing internal register accuracy using trigonometric function chains like arcsin(arccos(arctan(tan(cos(sin(9)))))). (00:20:15) Mentoring Dylan on Voltage Regulators: Dave talks about guiding his second-year intern, Dylan, through parametric searching to pick a 3V fixed regulator for an ESP32-based product. (00:24:00) LDO Stability & Package Selection: Dave delivers an impromptu masterclass on SOT-23 vs. SO-8 packages, LDO loop stability at microamp quiescent currents, transient responses for LCD/Bluetooth burst currents, and dielectric differences between Y5V and X7R capacitors. (00:27:30) AI PCB Design & Astra Announcement: They review OpenAI’s Astra demo showing automated KiCad schematic generation and live 4-layer PCB layout routing. (00:33:15) The Walmart Greeter of Electronics: Chris explains why he refuses to gatekeep hardware design as AI layout tools lower the barrier to entry, preferring to be “the Walmart greeter of electronics” welcoming newcomers into the field. (00:35:15) Debugging & The Middle Gap: They analyze the gap between simple AI-generated microcontroller boards and complex high-speed multi-gigabit hardware, questioning where new engineers will learn root-cause debugging when boards fail. (00:37:30) History of Auto-Routers: Dave points out that automated PCB placement, auto-routing, and neural net hype have existed in EDA tools for over 30 to 40 years. (00:40:15) KiCad, Bezier Curves, and Trace Cloning: Dylan asks why KiCad’s schematic editor supports Bezier curves, and Chris highlights past guest Ian Scott Johnson contributing trace characteristic cloning features to KiCad. (00:43:00) The Power of Open Formats: Chris emphasizes how text-based open formats like KiCad, FreeCAD, and Blender allow AI tools to hook into hardware design, referencing past guest Robert Fennis and open FEM solvers. (00:44:45) AI in Semiconductor Design: They touch on an Asianometry video covering Synopsys and Cadence AI chip design tools, stock market drops, and token-based pricing models. (00:46:30) Reverse Engineering the Rigol DNA800 Scope: Dave details tearing down and reverse-engineering the RF board on Rigol’s DNA800 (Digital Network Analyzer / VNA scope). (00:48:00) RF PCB Layout Techniques: They examine gold-shielded PCB arenas, surface traces vs. inner-layer vias, and unusual stripline couplers feeding IF signals back into the local oscillator. (00:50:45) Leaving Mistakes in Videos: Dave discusses accidentally misidentifying a DAC as an ADC in his teardown video and leaving the mistake in to show authentic reverse-engineering. (00:54:00) The Toaster Designer Story: Inspired by the book Red Rising calling robots “toasters,” Dave retells his classic story of turning down a job designing a constant-temperature toaster controller because “toaster repairman/designer” was an old forum running joke. (00:55:45) The Toaster Chip Legacy: Chris references Episode 541 where they previously discussed dedicated toaster ASICs. (00:58:00) Edge Lab Live at Electronica: Chris mentions Edge Lab Live running a hands-on engineering lab at Electronica in Munich this November. (00:59:15) Espressif Launches Linux BSP: Chris highlights Espressif quietly launching a Linux BSP for the ESP32-P4 chip, as shared on the Contextual Electronics forum thread. (00:59:45) Build Australia YouTube Creator Job: Dave shares a job opening from Build Australia seeking a YouTube creator to visit and film local Australian hardware and manufacturing companies. (01:00:30)

Chris welcomes Andy Kong to discuss “Chargerless” and how to build ultra-low-power wearable health trackers that never need wall charging. (00:00:15) From Hacker Mindset to Startup Founder: They discuss Andy’s background in biosensing, staying with Samy Kamkar, and bringing a pragmatic “get things done” hacker mindset to founding Chargerless in San Francisco, as documented on Andy’s personal website. (00:02:10) Solving the Wearable Charging Bottleneck: Andy explains how frustration with daily Apple Watch charging led him to design a wearable requiring only one minute of daily sunlight exposure, noting that modern wearables are bottlenecked by battery volume rather than logic chip size. (00:04:30) Deliberately Underpowered MCUs: Chris and Andy explore system architecture trade-offs, focusing on Chargerless’s choice of an underpowered microcontroller paired with lean firmware rather than feature-heavy, power-hungry processors. (00:07:15) Intelligent Sampling vs. Continuous Monitoring: They contrast Whoop and Apple Watch’s continuous PPG power drain with Chargerless’s periodic sampling approach, which reserves high-frequency tracking for active workout modes. (00:09:45) The Limits of Commercial Sensor ICs: Why off-the-shelf health ICs from TI and Analog Devices consumed 100 times too much power due to unoptimized ADCs, inefficient amplifiers, and fixed pulse timings. (00:12:20) EKG vs. Wrist PPG: Explaining how multi-lead chest EKGs measure electrical heart potential vectors, whereas wrist Photoplethysmography (PPG) uses green light reflection to detect oxygenated blood volume changes. (00:15:05) Badge Life and DIY Biometrics: Chris and Andy reminisce about community hardware projects like Chaos Camp’s Card10 EKG badge, Kerry Scharfglass’s IR-synchronized dragonfly badge, and Chris’s earlobe PPG sensor that flashed LEDs inside a Solo cup based “badge”. (00:17:50) Custom Discrete PPG Frontend: How Andy replaced commercial ICs with a discrete circuit that strobes a green LED 50 times per second for microsecond bursts, cycling both the LED and transimpedance amplifier. (00:20:40) Eliminating Decoupling Lag: Stripping decoupling capacitors removed turn-on delays, while using two amplifier stages avoided high-capacitance digital potentiometers. (00:23:10) Pivoting Away from BCI: Andy describes his college research on brain-computer interfaces (BCIs) with OpenBCI and why he abandoned non-invasive EEG due to microvolt-level signal noise from cable movement. (00:25:55) Quantified Self & Personal Informatics: Discussing how self-trackers capture environmental data to identify root causes of complex health symptoms. (00:28:30) Low-Power Bluetooth Data Batching: How Bluetooth Low Energy accounts for less than 5% of overall power draw by batching 10 KB payloads every 10 minutes for fast burst transmissions to the phone. (00:31:15) Form Factors and Ring Safety: Comparing Whoop, Oura, Garmin, and Fitbit Air trackers, while covering smart ring battery constraints, Samsung battery recall testing, and degloving risks. (00:34:00) Whoop’s Slide-On Battery: How Whoop designed a slide-on battery pack to charge while being worn, avoiding the user drop-off caused when devices are taken off to charge. (00:36:45) Solar Harvesting & Laser Dicing: Chargerless uses boost converters to harvest power from amorphous solar cells, which Andy initially custom diced with laser cutters at MIT. (00:39:20) Bare-Metal Registers & 28-Hour Days: Transitioning from dev boards to custom PCBs required low-level MCU register programming, custom Makefiles, and a 28-hour daily cycle sleep study in tinfoiled rooms. (00:42:10) Pricing & Open Data Access: Chargerless is rolling out a pre-production run of a few hundred units for $199 with no subscription fees on getchargerless.com and open data export capabilities. (00:45:00) Power Over Skin (Body Channel Communication): Andy breaks down his Power over Skin research project, which sends 40–100 MHz RF power safely through human skin using the body as an antenna. (00:47:45) Microwatt Energy Harvesting: Utilizing Skyworks low-forward-drop diodes, tank circuits, and rectifiers to harvest microwatts for powering LED earrings, ring joysticks, and skin patches. (00:50:30)

Kevin Cloutier is the North American Lead for Physical AI at CapGemini, a global engineering consulting firm. He is a computer engineer who is passionate about taking complex computations to the edge. He joins Chris to discuss the transition from legacy, statically programmed factory robotics to modern, imitation-learning-based “Physical AI,” building and calibrating the affordable $200 3D-printed SO101 robot arm using the LeRobot open-source framework or Intel’s Physical AI Studio, and orchestrating complex robotic systems entirely on local edge hardware. Timeline Chris welcomes Kevin Cloutier to discuss “Physical AI” and how it relates to robots and things that move in the physical world. (00:00:15) Meeting at Embedded World: They reminisce about meeting at the Canonical booth in front of a robot demonstration, which you can see in the Embedded World Demonstration Video. (00:02:10) Trade Shows and Geography: Chris and Kevin discuss Embedded World in Nuremberg, Germany, upcoming SPS, and the high concentration of manufacturing robots in Europe compared to the US. (00:03:50) The “Unicorn Developer” Shift: Kevin talks about his background in computer engineering and how the “unicorn developer” has shifted from the full-stack web developer of the 1990s to someone who can operate, program, repair, and train physical robots. (00:06:05) Factory Robots vs. Edge Cases: Contrasting legacy, statically programmed factory robots (like ABB or Universal Robots hanging car doors) with modern generative AI approaches capable of handling real-world edge cases. (00:09:15) The Robotics Software Stack: Demystifying the layers above motor drivers, including Real-Time Operating Systems (RTOS), Linux, and message-passing frameworks like ROS (Robot Operating System) and ROS 2. (00:12:40) Orchestrating Systems of Systems: Kevin describes playing tic-tac-toe using Vision Language Action (VLA) models, where a higher-level camera and computer vision system orchestrate the coordinates for the movement model. (00:15:10) The Evolution of Compute: How modern silicon, integrated GPUs, and SOCs have allowed the massive, heavy control boxes of legacy robots to shrink down to a small NUC-sized device mounted directly on the robot. (00:18:05) The SO101 Robot Arm: Introducing the SO101 3D-printed robot arm from Hugging Face, which democratizes robotics by allowing anyone to build a leader-follower setup for around $200. (00:21:20) How “Backyard Engineers” Learn: Kevin’s advice for firmware and hardware engineers stepping into robotics: follow the documentation, get it running, and then ask questions about what you don’t know. (00:23:55) Calibration and the LeRobot Framework: A look at using the LeRobot open-source framework to calibrate hobby-grade motors and define their movement limits. (00:26:40) Recording “Episodes” via Imitation Learning: How users physically guide the leader arm to control the follower arm while a webcam records the visual and servo coordinate data. (00:28:50) Training the Model: Organizing data into short 5-episode chunks to make deletion easier, and training the model locally on NVIDIA GPUs or in the cloud. (00:31:30) From Training to Evaluation: Moving from training to evaluating the custom model, and asking questions about action chunking, model stutter, and operating frequency. (00:35:10) Sensor Fusion vs. Pure Vision: The current dominance of cameras in physical AI, and the potential to fuse accelerometers and time-of-flight sensors on mobile robots like Autonomous Mobile Robots (AMRs). (00:41:00) Real-World Calibration Challenges: Kevin shares a story of someone knocking over his camera boom at Hannover Messe and how he used April Tags to quickly recalibrate the camera’s physical coordinates. (00:43:15) The Reality of Humanoids: Debunking humanoid hype and explaining why full humanoids are further out than the public thinks, due to immense hardware cost, degrees of freedom, and safety. (00:45:50) The Puppeteer behind the Curtain: Kevin points out that many impressive humanoid demos, like the Unitree G1 at Hannover Messe, are actually being teleoperated by an engineer standing nearby. (00:48:40) The Complexity of Robot Subsystems: Using Steve Crunch and the book “Exploding the Phone” as an analogy for how modern robotic systems have become too complex for a single human to fully understand. (00:52:15) Understanding SmolVLA and SmolVLM: Diving under the hood of Vision Language Action models, which are fine-tuned transformer models that translate visual inputs into physical robotic coordinates. (00:55:10) Local AI and the NPU: How modern System-on-Chips (SOCs) let engineers run models locally on the CPU, GPU, or Neural Processing Unit (NPU) using optimization toolkits like Intel OpenVINO. (00:58:15) The Joy of the Physical World: Why working with physical hardware and robots is far more creative and rewarding than optimizing spreadsheets or SaaS applications. (01:04:30) “If the Robot Can’t Kill You, It’s Not Fun”: Kevin shares his colleague’s favorite metric for a truly exciting robotics project. (01:07:10) Advice on ROS and “Cobbling”: Starting with duct tape and bubble gum, and learning message-passing frameworks like ROS only when you need to coordinate multiple independent robots. (01:09:30) Physical AI Studio Demo: An invitation to see Kevin showcase Intel’s Physical AI Studio with multiple active robots at the upcoming AI Infra conference in Santa Clara. (01:14:45) Find Kevin online at his website cloutier.engineer or on LinkedIn. (01:20:10)

Robert Fennis is an RF engineer and consultant from the Netherlands and the creator of EMerge: a free, open-source 3D Finite Element Method (FEM) electromagnetic solver written in Python. He joins Chris to discuss demystifying the black magic of RF engineering, the mathematical and physics foundations of simulation, and how Emerge is “the IKEA of FEM solvers” in that it makes electromagnetic simulation accessible to everyone. Timeline Chris welcomes Robert Fennis, creator of EMerge, to discuss RF simulation as a way to unlock knowledge of the universe. (00:00:15) LinkedIn Shout-outs: Chris and Robert praise the amazing RF visualizations done by past guests Lukas Henkel, Sam Aldahar, and Katerina Galitskaya. (00:01:20) The Wizard School of RF: They discuss how RF engineering is often seen as a black magic wizard school of electronics, despite being normal to Robert. (00:03:10) Pyramid of Knowledge: Robert explains how learning RF and simulation is like building a pyramid step-by-step, where you have to understand waves, ports, and S-parameters rather than trying to build it all from scratch. (00:05:00) Python and LLMs: EMerge is written as a Python module but utilizes fast external libraries under the hood. They talk about how script-based engineering allows LLMs to assist by writing simulation code from existing examples on the EMerge Hub on GitHub. They draw a comparison to OpenSCAD’s parametric code-first approach in mechanical design. (00:07:30) The Big Three Full-Wave Simulation Methods: Robert explains how full-wave solvers attempt to approach exact solutions to Maxwell’s equations. (00:11:30) Finite Difference Time Domain (FDTD): A time-stepping method that operates similarly to movie physics engines, marching forward in time. (00:12:15) Method of Moments (MoM): A method solving specifically for currents and voltages on conductors, using Green’s functions to calculate interactions without discretizing the surrounding air. (00:13:40) Finite Element Method (FEM): A frequency-domain solver derived from variational calculus (the Principle of Least Action). It solves for complex electric fields in the airspace surrounding conductors, treating conductors as boundary constraints. (00:15:10) The Veritasium Switch Video: They connect the physics of FEM to the famous Veritasium switch debate, noting that energy travels outside of wires. This is why FEM solvers must discretize the surrounding airspace to capture the physics, as famously illustrated in the Veritasium switch video. (00:18:20) The Challenges of Real-World Boundaries: In FEM, boundary conditions define where the simulation ends. Choosing the right boundaries is critical because perfect electric conductors can introduce unrealistic internal resonances. (00:20:45) Simplifying vs. Overcomplicating Models: Mentor advice on simplifying models to ensure convergence. Robert warns that adding too much detail quickly exhausts RAM, which is currently expensive. (00:22:15) Frequency and Detail: A rule of thumb is that higher frequencies make small details matter more. Right-angled corners on PCB traces act as parasitic capacitors at 10 GHz, and silk screen on a 2.4 GHz patch antenna can completely de-tune it. (00:24:30) Bluetooth Antenna Design Workflow: Chris shares his fear of designing custom 2.4 GHz antennas for boards like the NRF52840. Robert outlines his step-by-step customer consultation process, evaluating orientation and directivity (omnidirectional vs. directional). (00:32:15) The Logarithmic Scale of Decibels: Squeezing S11 reflection coefficients from -20 dB to -25 dB only wins a fraction of a percent of energy. Since receivers have massive dynamic ranges, aiming for -10 dB or even -5 dB is often perfectly fine for non-critical systems. (00:36:40) The Incremental Design Method: Instead of modeling the entire system, start with the simplest geometry (e.g., a simple square patch or wire). Find the length where it resonates, and then introduce components like plastic enclosures, screws, or clips one by one to see how they shift the resonant frequency. (00:41:20) Working with Ports in EMerge: EMerge uses lump ports (numbered starting from 1) for PCBs and computes S-parameters like S11, which can be plotted on a logarithmic scale with the built-in plot_SP function. (00:44:50) Alternative EMerge Applications: (00:47:45) PCB Filters: Designing microstrip and coupled-line filters on FR4 or Rogers substrates. FR4 is risky due to variations in refractive index, making simulation validation highly valuable before spending money on expensive substrates. (00:48:10) Radar Cross-Section (RCS): Modeling how objects scatter electromagnetic waves. (Note: Large stealth bombers are computationally impractical for EMerge, but smaller models work). (00:51:30) Power Dividers: Tuning Wilkinson power dividers. (00:52:45) Crosstalk and Signal Integrity: Making sure high-speed 1 Gbps bitstreams arrive intact without degrading or leaking into other ports. You can view an example crosstalk simulation on the EMerge Showcase page. (00:53:30) Under-the-Hood Engineering and Performance: (00:55:00) Robert shares his story of spending a week straight getting 3D solver matrices to assemble and solve. (00:55:15) He highlights that 98% of the effort in building a solver is computational geometry (meshing), for which EMerge uses the GMSH library. (00:58:30) Linear algebra is solved using Intel MKL on x86 platforms (thanks to Olaf Schenk) and Apple Accelerate on macOS (thanks to Dr. Jonathan Hogg). (01:00:15) The solver assembles sparse coordinate matrices converted into compressed column storage. (01:02:00) Robert wants EMerge to be the IKEA of FEM solvers—not perfect, but free, accessible, and good enough. (01:03:50) The Nightmare of Importing PCBs: Why computational geometry makes importing PCBs incredibly difficult. (01:08:15) Gerber Files: Aperture-based photographic formats. Approximating circles with polygons can lead to tiny gaps that crash mesh engines. (01:09:45) STEP Files: They model trace thickness physically (which is unnecessary for EMerge) and cause floating-point rounding errors on round holes. (01:11:30) ODB++: Robert is using Claude/AI to help write an ODB++ parser. (01:13:00) Method Chaining and the Builder Pattern: An alternative to importing CAD files is describing geometry programmatically using a method chaining philosophy in Python (e.g., drawing traces with straight, turn_right, and skip functions). This forces the user to keep things simple, making the design additive rather than subtractive. (01:15:45) Closing Thoughts and Consulting: Robert runs a consulting business but emphasizes that the open-source software is GPLv2 and has no warranty. He prefers teaching clients how to use the software and run simulations themselves. You can connect with Robert and other RF simulation enthusiasts via the EMerge Discord community. (01:19:30) Recommended Reading List The Finite Element Method in Electromagnetics by Jian-Ming Jin (the mathematically dense Bible of FEM) Davidson’s electromagnetics textbook Computational Electromagnetics with MATLAB by Matthew M. Sadiku (an accessible textbook that can be translated to Python or Octave)

ACES Hardware Meetup: Dave recently attended a packed ACES Hardware meetup at the Engineers Australia headquarters, which led to a discussion on whether “Engineer” should be a protected term like “Doctor” or “Lawyer”. Naming Rant: If your startup doesn’t delete vowels (like “X trainer”) or use an un-Googleable name like “Drop Bear,” are you even trying? Dave also shares his frustrations with names like “Goliath” and “Mindvault”. The New Website: Chris reveals the new, blazing-fast static site for TheAmpHour.com, built using Hugo and Claude. It features searchable transcripts for every episode and a “pissed-old amber” SVG scope animation where the focus knob actually works. New Merch: Amp Hour Retro Gauge shirts are back, along with the new RF-themed “Beyond Return” Smith Chart Seance shirt (inspierd by Veritasium’s latest video about the history of Smith Charts). There is even a rug that doubles as part storage, though shipping to Australia is pricey. Dave’s New Hire: Dylan joins the EEVblog team to help with video content, editing, and potentially working on products. Shipping SaaS: Dave rants about the arbitrary limits on shipping labels for services like “Star Ship It” and the unfortunate “cost of doing business”. Microchip Goes Free: The MPLAB XC Pro compilers are finally free 15 years too late. This brings up memories of the podcast episode with Microchip CEO Steve Sanghi. 10-Cent Debuggers: Discussing how the 10-cent CH32V003 can be used as a debugger for other chips. Also, check out these ESP32 Bit Pirate web tools for hardware testing. We have had CNlohr (Creator of the CH32fun library) on two times. 59:30 – Bot Traffic & Pay-Per-Crawl: Discussing Cloudflare’s new pay-per-crawl “toll booth” for AI crawlers and a mysterious Chinese bot hammering a specific forum thread. 68:00 – 1.5 Million Hits: How the 12-year-old static site engineerblogs.org is suddenly getting massive traffic from unknown bots. 73:00 – Rigol’s Tiny VNA: The new Rigol DNA800 series packs a 14 GHz VNA into a handheld form factor. 78:30 – Solar Inverter Explosions: Shahriar from The Signal Path recently had a “magic smoke” event where he had to replace 16 MOSFETs on his inverter board.