Levitating Globe Teardown, Part 2
Tim Wescott opens up a budget levitating globe and shows why it seems magical: a massive 30 mm rare-earth magnet and a deliberately cheap magnetic circuit. He documents a bolt used as the flux core, a likely microcontroller and hall sensor in the head, very fine winding in the electromagnet, and a single-transistor unidirectional drive. Part 3 will measure forces and sensor voltages to build a better controller.
Levitating Globe Teardown, Part 1
Tim Wescott buys a $30 floating-globe desk toy and walks through first impressions, hands-on magnet experiments, and a frank critique of its control system. He highlights the toy's underdamped response, uni-polar electromagnet tradeoffs, and simple hacks that reveal clues about the pole pieces and magnet layout. This is a practical, engineer-forward preview before the actual teardown in part two.
Another 10 Circuit Components You Should Know
Jason Sachs walks through ten underrated circuit components every embedded engineer should know, from bus switches and thermocouple signal ICs to PCB stiffeners and opto-FET isolators. He mixes practical part examples, high-current hardware tips, and MCU features like CTMU and Peripheral Pin Select so you can pick the right trick when space, isolation, or precision matter.
Short Takes (EE Shanty): What shall we do with a zero-ohm resistor?
When you need flexibility on a PCB, zero-ohm resistors are the obvious shortcut, but Jason M. Sachs shows why the label zero is misleading. He compares common SMT jumper specs, high-current specialty parts, and a practical workaround using 1 milliohm resistors to avoid voltage drop. Read this for a quick checklist to pick jumpers that actually carry your board's current.
Arduino robotics #3 - wiring, coding and a test run
Lonnie Honeycutt walks through wiring, coding, and the first test run of Clusterbot, a budget Arduino robot build costing about $50. The post provides a clear pin-mapping to the TB6612FNG motor driver, ready-to-upload Arduino movement functions, and practical tips like tinning thin battery wires. You also get PWM calibration values and the measured RPM timing the author used to make reliable turns.
Arduino robotics #2 - chassis, locomotion and power
Lonnie Honeycutt walks through building Clusterbot's round differential-drive chassis, showing how a circular base and Tamiya gearbox simplify turning and torque tradeoffs. The post covers motor selection, wheel fit, balance issues, and a practical two-battery power arrangement with VMOT for the motors and a separate 9V for the Arduino. Expect hands-on tips and lessons learned from a first-time robot build.
Arduino robotics #1 - motor control
Clusterbot is Lonnie Honeycutt's first autonomous robot, built on a tight budget to teach practical motor control. This post explains why you cannot drive motors directly from an Arduino, how to wire and enable the Toshiba TB6612FNG motor driver, and offers hands-on PWM and calibration tips for getting smooth motion from cheap Mabuchi FA-130 toy motors.
Introduction to Microcontrollers - Adding Some Real-World Hardware
Two blinking LEDs only teach you so much, so Mike designed a docking board that adds a 4x20 HD44780 LCD, a 4x4 button matrix, four LEDs, DIP switches and an ADC potentiometer for AVR and STM32 experiments. This post shows how to wire and drive the HD44780 in 4-bit mode, calibrate microsecond and millisecond software delays, use the busy flag to speed writes, and includes AVR example code to get the display running.
Introduction to Microcontrollers - More On GPIO
Polarity matters: an output '1' does not always mean an LED lights, and inputs are just as picky. This post walks through LED driving basics, pull resistors for buttons, and practical bitwise techniques to read and write individual GPIO pins on AVR and STM32 boards. It also explains why polling rates and mechanical bounce make button handling trickier than it looks and what to watch for next.
Lost Secrets of the H-Bridge, Part III: Practical Issues of Inductor and Capacitor Ripple Current
Jason Sachs cuts through the math to show what ripple current actually does to H-bridge hardware. He explains why peak current is the limiting factor for inductors, why capacitor ESR usually dominates DC-link voltage ripple, and how center-aligned PWM and duty selection reduce harmonics and ripple. Read this if you want practical rules of thumb and calculation templates for real power-electronics designs.
Improving the Reload2 active load
Fabien Le Mentec takes a low-cost Reload2 active load and turns it into a programmable test tool. By swapping the manual setpoint for a Teensy 3.1 DAC and replacing the op-amp with a chopper amplifier, he gets software-controlled current profiles and lowers the minimum load current to about 7 mA. It is a practical hack for testing power supplies and Ethernet-powered boards under realistic startup and sleep conditions.
Introducing The VolksEEG Project
VolksEEG is an open-source effort to build an FDA-cleared clinical EEG and publish every design so others can manufacture it. The volunteer-driven project centers on the TI ADS1299 8-channel, 24-bit biopotential ADC and combines medical and electrical engineering expertise to confront regulatory, safety, and usability challenges. This blog series will document technical decisions, isolation and safety concerns, and ways engineers can contribute.
On optimizing manual soldering
When faced with manual soldering of thousands of components, speed and efficiency become pivotal. Here are some takeaways from my own experience attempting to optimize such a process.
Quickfire Heuristics: A Fast Usability Evaluation Framework for Lean Hardware Teams
That device with the single LED that requires you to count blink patterns just to understand system status. The button you must hold for 8 seconds, which also performs four other actions depending on hold duration. These are not accidents of negligence; they are the predictable output of development processes that have no rigorous usability evaluation component. Usability tends to slip through the gaps of standard engineering reviews, surfacing late, when design flexibility is already gone. This article introduces a framework that adapts Jakob Nielsen's Ten Usability Heuristics, for hardware and embedded systems, translating each principle into concrete evaluation questions for physical interfaces, firmware state machines, constrained displays, and cross-layer interactions. Using a smartwatch as the running example, it also introduces a structured session format, maps the framework to key lifecycle stages, and extends it to manufacturing, test, and field service contexts.
Autonomous vehicle - design questions to ponder
Designing an autonomous or remotely controlled vehicle forces tradeoffs between purpose, environment, and terrain. This post lists practical questions to drive decisions about mission profile, ruggedization, power and data handling, sensing, and modularity so your robot survives and completes tasks. Engineers will get a concise checklist to provoke design choices and avoid common failure modes in real-world deployments.
Designing IoT Wireless Sensor Nodes
Mahesh Balan outlines practical strategies for building tiny IoT wireless sensor nodes that run on harvested energy. The post explains using small solar cells with coin-cell or supercapacitor buffering, pairing sensors with Bluetooth Low Energy for short-range telemetry, and choosing PMICs with ultra-low quiescent and startup power. A Cypress PMIC example shows operation can be sustained under low-brightness conditions near 100 lx.
Software is free and can right any wrong
Software changes are so much easier than hardware modifications, so the temptation is always to take this approach to fixing bugs. This may not always be a good idea.
Wye Delta Tee Pi: Observations on Three-Terminal Networks
Three-terminal passive networks, wye, delta, tee, and pi, are more interchangeable than many engineers expect. Jason Sachs walks through Kennelly's wye-delta formulas, Z and Y matrix representations for tee and pi two-port networks, and worked examples ranging from balanced to highly skewed impedances. The post highlights practical payoffs, including using topology transforms to substitute hard-to-source capacitors with simpler, precision-friendly parts.
It ain't heavy, it's my robot...
For anyone building a man-portable unmanned ground vehicle this post collects practical design constraints and mission trade-offs engineers actually face. It summarizes weight and cost classes, locomotion options from throwables to wheeled skid-steers, sensor and camera requirements, power and battery strategies, communications range, and field-repair issues. Use it as a checklist to match platform choices to intended tasks and environments.
Short Takes (EE Shanty): What shall we do with a zero-ohm resistor?
When you need flexibility on a PCB, zero-ohm resistors are the obvious shortcut, but Jason M. Sachs shows why the label zero is misleading. He compares common SMT jumper specs, high-current specialty parts, and a practical workaround using 1 milliohm resistors to avoid voltage drop. Read this for a quick checklist to pick jumpers that actually carry your board's current.
Metal detection: building the detector
Fabien Le Mentec turns a bench-validated BFO stage into a field-ready metal detector using scavenged parts and straightforward fabrication. He moves the circuit from breadboard to a through-hole prototyping PCB, swaps the Arduino Nano for a lower-power Mini, and builds an ABS control box with buttons and a buzzer. The build uses a 2S LiPo pack with a 5V LDO and a nonmagnetic coil mount, with practical notes on tradeoffs and safety.
Making a connection 1
Reliable electrical connections are the unsung foundation of any embedded system, yet connector selection and technique are often overlooked. This practical primer walks through common terminal styles, when to solder versus crimp, basic crimping steps and tool choices, plus simple checks and color-coding rules to help you make durable, serviceable wire connections without surprises.
Here Comes The Noise!
Noise. That awful thing which nobody wants that most sadly never learn about. It's time to change that with this blog post.
Deeply embedded design example - Logic replacement
Gene Breniman shows how a tiny PIC10F200 can replace a forest of discrete timing components to control six 10A H-bridges, letting firmware tune sequencing to cut EMI and reduce cost. He walks through analyzing the original RC/inverter delays, choosing the PIC, pinout and timer setup, and implementing compact assembly firmware that reproduces and improves the timing behavior. The result is fewer parts, saved board space, and better EMI control.
A Useful Current Profiling Method
Dr Cagri Tanriover shares a practical, low-cost way to capture millisecond-scale current profiles when you do not have a DSO. The method uses a 0.3 ohm shunt, an LM324 amplifier with roughly 11x gain, and a microcontroller ADC to log 10-bit samples at 20 kHz, giving sub-millisecond timing and about 1.15 mA sensitivity for embedded radio measurements.
Circuit Board Standoffs
Can't find the exact standoff size for your PCB? This post shows how to fabricate custom standoffs from tubing or solid rod, with practical guidance on material choices, measurement, cutting, lathe facing, and drilling and tapping. The walkthrough uses brass as an accessible option, lists the correct drill size for 4-40 screws, and explains how to create chassis threads if needed.
Interfacing with Electrochemical Gas Sensors
Stephane Boucher lays out practical rules for connecting electrochemical gas sensors to amplifiers and mixed-signal MCUs. He explains the potentiostat and transimpedance amplifier topology, why the reference electrode must see sub-nanoamp currents, and how GPIO structures in devices like the PSoC 4 can introduce leakage. The post shows how choosing supply and reference voltages yields a near-zero input-current operating point for reliable sensing.
OS influence on power consumption
Power consumption of an embedded system may be influenced in software in general, but selection of an operating system can be key.
Introducing The VolksEEG Project
VolksEEG is an open-source effort to build an FDA-cleared clinical EEG and publish every design so others can manufacture it. The volunteer-driven project centers on the TI ADS1299 8-channel, 24-bit biopotential ADC and combines medical and electrical engineering expertise to confront regulatory, safety, and usability challenges. This blog series will document technical decisions, isolation and safety concerns, and ways engineers can contribute.
Better Hardware Design Decisions, Faster: A Lean Team’s Guide to MDO
As design complexity grows, siloed decision-making often leads to late-stage surprises, costly rework, and missed opportunities for optimization. Multidisciplinary Design Optimization (MDO) offers a structured approach to solving this by enabling teams to evaluate trade-offs and impacts across the full system before implementation begins. Traditionally used in large, high-budget industries like aerospace, MDO is now within reach for lean teams, thanks to more accessible modeling tools and an urgent need for tighter collaboration. This article outlines how small hardware teams can adopt MDO in a practical way, starting simple, integrating key models early, and building toward a culture of systems thinking. The result is better design decisions, faster development, and more robust, manufacturable products with fewer surprises along the way.
