Your architecture was decided before you opened the schematic
Engineering teams often treat requirements as a simple feature checklist, but they actually hold the blueprint for your software architecture. By analyzing constraints collectively rather than in isolation, you can define critical architectural patterns—such as task scheduling and abstraction levels—long before the first schematic is drawn. This proactive approach eliminates wasted complexity, reduces development time, and allows software needs to inform hardware choices early in the cycle. Discover how to shift your design mindset to build lean, purposeful systems that align perfectly with business objectives from day one.
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.
Beware of Analog Switch Leakage Current
Leakage currents in analog switches can quietly wreck precision reference circuits at elevated temperature. Jason M. Sachs walks through three switch-topology implementations for a switchable 1.25 V reference and shows which topology gives the smallest worst-case output error using real part specs. He explains why op amp input bias is usually negligible and gives practical fixes: lower resistances, better switches, or limiting temperature range.
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.
How to Analyze a Three-Op-Amp Instrumentation Amplifier
The three-op-amp instrumentation amplifier gives you high input impedance, improved net bandwidth, and much lower sensitivity to resistor mismatch than a single-op-amp differential stage. Jason M. Sachs walks through the algebra, numeric examples, and historical notes to show how the preamp isolates common-mode, why splitting gain boosts bandwidth, how overall gain can be set with one resistor, and what practical limits to watch.
How to Design Reliable Reset Circuits for Embedded Microcontrollers
In the world of embedded systems, the reset circuit is a critical component that ensures the microcontroller starts up correctly and recovers gracefully from unexpected events like power fluctuations or software crashes. A poorly designed reset circuit can lead to erratic behavior, system lockups, or even permanent damage to the microcontroller. For embedded engineers, designing a reliable reset circuit is essential for ensuring the stability and robustness of the system.
The Most Annoying Sound
Independent consultants often face requests and requirements that go beyond the technicalities of software and hardware. Designing user interfaces is a common example, and even though most of us are not UI experts, we still have to get it right, otherwise the users may get annoyed, and the product will fail. However, what happens when we're asked explicitly to annoy users? Here's a true story about such a case.
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.
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.
Stand-by or boot-up
Many factors affect the usability of devices - a key one is how long it takes to start up.
Tolerance Analysis
Jason Sachs walks through practical tolerance analysis by designing a 24V overvoltage detector from the ground up, combining resistor tolerances, temperature coefficients, reference and comparator errors, hysteresis, and dynamic RC behavior. He demonstrates worst-case stacking with real datasheet numbers, shows how solder and mechanical stress affect resistor choice, and sizes filtering so the comparator meets a microsecond-range trip requirement. The article is a hands-on guide full of worked examples and trade-offs for embedded hardware engineers.
Lost Secrets of the H-Bridge, Part V: Gate Drives for Dummies
Learn the most important issues in power MOSFET and IGBT gate drives: - Transistor behavior during switching - Calculating turn-on and turn-off times - Passive components used between gate drive IC and transistor - Reverse recovery - Capacitively-coupled spurious turn-on - Factors that influence a good choice of turn-on and turn-off times - Gate drive supply voltage management - Bootstrap gate drives - Design issues impacting reliability
VHDL tutorial - A practical example - part 1 - Hardware
Gene Breniman walks through a practical CPLD-based data acquisition engine built for a low-power handheld instrument, focusing on hardware choices, signal flow, and pin assignments. The article explains component selection including a PCM1870 ADC, CY14B101Q2 serial nvSRAM, and an XC2C64A CPLD, and shows how the CPLD acts as an SPI sequencer and I2S clock master while minimizing microcontroller pins and power draw.
How to Read a Power MOSFET Datasheet
Jason Sachs takes a soapbox to stop a recurring mistake: misreading power MOSFET datasheets. This practical guide separates marketing blurbs and typical graphs from the specifications you can actually rely on, and explains how to use RDS(on), VGS, gate charge, SOA and thermal data in real designs. Read this before you pick a MOSFET or size a gate driver.
Lost Secrets of the H-Bridge, Part IV: DC Link Decoupling and Why Electrolytic Capacitors Are Not Enough
Switching H-bridges can kick nasty voltage spikes onto the DC link, and a single electrolytic capacitor rarely fixes the problem. Jason Sachs uses simulations and practical PCB layout advice to show how a three-tier decoupling strategy — bulk electrolytic, mid-value ceramics or film, and many small HF bypass capacitors plus PCB plane capacitance — tames spikes, reduces EMI, and avoids harmful resonances when parts and vias are placed correctly.
7 Essential Steps for Reducing Power Consumption in Embedded Devices
Reducing the amount of power your embedded device is consuming is not trivial. With so many devices moving to battery operations today, maximizing battery life can be the difference between a happy, raving customer and an unhappy one that ruins your company's reputation. This post explores seven steps for optimizing your embedded systems' power consumption. You'll gain insights into the steps and techniques necessary along with receiving a few resources to help you on your journey.
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.
Second-Order Systems, Part I: Boing!!
Jason Sachs takes the spring 'boing' of a doorstop into the math of second-order systems, using the series LRC circuit as a concrete example. He shows two standard transfer-function forms, explains why ωn only scales time while ζ sets the response shape, and derives pole locations plus an exact overshoot formula that helps tune embedded-system responses.
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.
How to Analyze a Three-Op-Amp Instrumentation Amplifier
The three-op-amp instrumentation amplifier gives you high input impedance, improved net bandwidth, and much lower sensitivity to resistor mismatch than a single-op-amp differential stage. Jason M. Sachs walks through the algebra, numeric examples, and historical notes to show how the preamp isolates common-mode, why splitting gain boosts bandwidth, how overall gain can be set with one resistor, and what practical limits to watch.
How to Read a Power MOSFET Datasheet
Jason Sachs takes a soapbox to stop a recurring mistake: misreading power MOSFET datasheets. This practical guide separates marketing blurbs and typical graphs from the specifications you can actually rely on, and explains how to use RDS(on), VGS, gate charge, SOA and thermal data in real designs. Read this before you pick a MOSFET or size a gate driver.
Thermistor signal conditioning: Dos and Don'ts, Tips and Tricks
Jason Sachs shows how to keep thermistor conditioning simple and accurate for embedded systems. He warns against analog linearization and excessive analog stages, and explains why ratiometric dividers, proper ADC buffering, and using the same reference voltage give better results. The post also covers thermal pitfalls like self-heating and lead conduction, plus practical tips for ADC autocalibration and polynomial temperature conversion.
Analog-to-Digital Confusion: Pitfalls of Driving an ADC
Wayne's thermistor board showed one ADC channel changing when another was heated, a classic case of ADC input cross-coupling. The post walks through how multiplexed ADCs, the small sample-and-hold capacitor, source impedance, sampling time, repeated sampling rates, and added charge reservoirs interact to create errors. Learn practical fixes including increasing sample time, sizing external caps, adding op-amp buffers, and using an RC dampener with PCB layout tips.
Byte and Switch (Part 1)
Driving a 24V electromagnet from a 3.3V microcontroller looks trivial, but Jason Sachs shows how that simple switch can fail spectacularly. He walks through the cause of MOSFET destruction when an inductive load is turned off, and explains the practical fixes you actually need: a flyback diode, a gate series resistor, and a gate pulldown to keep the transistor well behaved.
10 Circuit Components You Should Know
Jason Sachs pulls together ten underrated but highly practical circuit components that every embedded engineer should know. From multifunction logic gates that act like a Swiss Army knife for glue logic to TL431 shunt regulators and tiny charge-pump inverters, each item is presented with real-world use cases and caveats. Read this to expand your parts toolbox and simplify future designs.
Lost Secrets of the H-Bridge, Part V: Gate Drives for Dummies
Learn the most important issues in power MOSFET and IGBT gate drives: - Transistor behavior during switching - Calculating turn-on and turn-off times - Passive components used between gate drive IC and transistor - Reverse recovery - Capacitively-coupled spurious turn-on - Factors that influence a good choice of turn-on and turn-off times - Gate drive supply voltage management - Bootstrap gate drives - Design issues impacting reliability
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.
Lost Secrets of the H-Bridge, Part IV: DC Link Decoupling and Why Electrolytic Capacitors Are Not Enough
Switching H-bridges can kick nasty voltage spikes onto the DC link, and a single electrolytic capacitor rarely fixes the problem. Jason Sachs uses simulations and practical PCB layout advice to show how a three-tier decoupling strategy — bulk electrolytic, mid-value ceramics or film, and many small HF bypass capacitors plus PCB plane capacitance — tames spikes, reduces EMI, and avoids harmful resonances when parts and vias are placed correctly.
VHDL tutorial - A practical example - part 1 - Hardware
Gene Breniman walks through a practical CPLD-based data acquisition engine built for a low-power handheld instrument, focusing on hardware choices, signal flow, and pin assignments. The article explains component selection including a PCM1870 ADC, CY14B101Q2 serial nvSRAM, and an XC2C64A CPLD, and shows how the CPLD acts as an SPI sequencer and I2S clock master while minimizing microcontroller pins and power draw.
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.
