Have You Ever Seen an Ideal Op-Amp?
Forget the ideal op-amp fantasy, Jason Sachs walks through the practical nonidealities that make textbook gain formulas fail in real circuits. Using the uA741C and TLC081C as examples, he explains offset voltage, input bias and offset currents, common-mode and supply rejection, gain-bandwidth and slew-rate limits, plus capacitive loading, RF rectification and overload recovery. Read to learn which datasheet specs matter and why.
10 More (Obscure) Circuit Components You Should Know
Jason Sachs follows up his earlier primer with ten more underused but practical parts that can simplify embedded hardware designs. From MOSFET-based ideal diode controllers that eliminate diode drops to TAOS light-to-frequency sensors that expand dynamic range, the post explains what each component does, when to choose it, and real-world tradeoffs learned from field use. Ideal for engineers looking to broaden their parts toolbox.
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.
C++ on microcontrollers 4 – input pins, and decoding a rotary switch
Wouter van Ooijen shows how to extend a small C++ I/O library for microcontrollers to support input pins and mixed I/O, and how to decode a rotary switch reliably. The post walks through a safe class hierarchy for input, output, and bidirectional pins, then builds a quadrature decoder with a saturating counter and an HC595 seven-segment demo you can run on LPCXpresso hardware.
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.
Real-time clocks: Does anybody really know what time it is?
Most RTC chips still expose calendar fields rather than seconds-since-epoch, forcing embedded engineers to write ugly conversion code. Jason Sachs makes the case for offset encoding, subseconds, and an explicit snapshot feature to simplify interval math, raise precision, and avoid rare timing bugs. Read this practical take on RTC trade-offs and a short wishlist for chip makers.
VHDL tutorial - A practical example - part 2 - VHDL coding
Gene Breniman walks through the VHDL coding for a CPLD-based data acquisition engine, turning the hardware spec into a working state machine and signal generators. The article explains SPI and I2S timing choices, an internal SPI peripheral latch, and counter-based timing (seqCount and CycleCnt) used to create LRCK, BCK, SPI SCK and nvSRAM write control. It’s a practical, implementation-focused guide for embedded designers.
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.
Byte and Switch (Part 2)
Running a thermistor front end from a single AA cell exposes problems you might not expect. Jason Sachs walks through a switchable-gain divider using a P-channel MOSFET and shows how MOSFET off-state leakage and low supply voltages can corrupt high-impedance temperature readings. The post compares bipolar transistors and analog switch ICs as fixes and gives practical component guidance for one-cell designs.
VHDL tutorial - combining clocked and sequential logic
Need the ADC clock to sometimes be the raw 40MHz input? Gene Breniman shows how to extend a reloadable, counter-based VHDL clock divider to support a master-clock pass-through by using a conditional signal assignment to switch between the internal ADCClk and Mclk. The article also covers remapping ClkSel values and includes a working XC2C32A CPLD build that leaves room for future enhancements.
How to use analog input (ADC) on NuttX RTOS
Hands-on walkthrough showing how to read analog voltages on a Raspberry Pi Pico running NuttX RTOS. The post explains RP2040 ADC basics, which GPIO channels and the internal temperature sensor are exposed, and how rp2040_adc_setup creates /dev/adc0. It also shows the menuconfig options, build and UF2 flash steps, a simple potentiometer test, and a note about RP2040 ADC spike artifacts.
Have You Ever Seen an Ideal Op-Amp?
Forget the ideal op-amp fantasy, Jason Sachs walks through the practical nonidealities that make textbook gain formulas fail in real circuits. Using the uA741C and TLC081C as examples, he explains offset voltage, input bias and offset currents, common-mode and supply rejection, gain-bandwidth and slew-rate limits, plus capacitive loading, RF rectification and overload recovery. Read to learn which datasheet specs matter and why.
MSP430 LaunchPad Tutorial - Part 3 - ADC
Enrico Garante walks through practical ADC use on the MSP430G2231, from a single-channel read that toggles LaunchPad LEDs to multi-channel repeated conversions. The post includes complete code, an ADC10 interrupt example to wake from low-power mode, and a DTC-backed array transfer so you can collect samples without polling. A short CCS debugging tip shows how to watch ADC variables while running.
Byte and Switch (Part 2)
Running a thermistor front end from a single AA cell exposes problems you might not expect. Jason Sachs walks through a switchable-gain divider using a P-channel MOSFET and shows how MOSFET off-state leakage and low supply voltages can corrupt high-impedance temperature readings. The post compares bipolar transistors and analog switch ICs as fixes and gives practical component guidance for one-cell designs.
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.
VERY Fast Japanese Sumo Robots
Japanese sumo robots can be oddly mesmerizing, and this short post captures that perfectly. Stephane Boucher shares a quick reaction to a video and points out the parts embedded engineers would want to hear about, like the sensors, microcontroller, algorithms, and design challenges behind the machine. It is more of a teaser than a teardown, but it makes a strong case for a deeper technical writeup.
LCD Control with an MCU
Dr Cagri Tanriover set out to add a cheap 2x16 JHD162A LCD to an MCU project and ran into surprisingly opaque datasheets and quirky behavior. This post walks through the wiring, a reliable initialization sequence, contrast troubleshooting, and practical scrolling and CGRAM tips that saved debugging time. Read it for hands-on fixes and gotchas that datasheets often omit.
C++ on microcontrollers 4 – input pins, and decoding a rotary switch
Wouter van Ooijen shows how to extend a small C++ I/O library for microcontrollers to support input pins and mixed I/O, and how to decode a rotary switch reliably. The post walks through a safe class hierarchy for input, output, and bidirectional pins, then builds a quadrature decoder with a saturating counter and an HC595 seven-segment demo you can run on LPCXpresso hardware.
Painting with Light to Measure Time
When Jason Sachs needed to verify a first-order sigma-delta LED dimming implementation but had no oscilloscope, he turned to long-exposure "light painting" to turn time into space on a photograph. By sweeping the camera across blinking LEDs he captured pulse trains, read the bit patterns from the light trail, and confirmed the result with a tiny Python accumulator model. The post shares practical tips on timing accuracy, exposure, and avoiding ambient-light artifacts.
Practical protection against dust and water (i.e. IP protection)
Needing IP65 protection while exposing humidity and pressure sensors on a tight $15 budget, Dr Cagri Tanriover hunted for a practical fix. He found that an SHT2x humidity sensor with a microporous filter cap and O-ring provides IP67-level protection, and by matching a pressure sensor that fits the same cap he met and exceeded the IP65 requirement. The post shows a low-cost, component-level workaround.
How to use analog input (ADC) on NuttX RTOS
Hands-on walkthrough showing how to read analog voltages on a Raspberry Pi Pico running NuttX RTOS. The post explains RP2040 ADC basics, which GPIO channels and the internal temperature sensor are exposed, and how rp2040_adc_setup creates /dev/adc0. It also shows the menuconfig options, build and UF2 flash steps, a simple potentiometer test, and a note about RP2040 ADC spike artifacts.
VolksEEG Project: Initial Hardware Architecture
The VolksEEG prototype pairs an Adafruit Feather nRF52840 Sense MCU with an ADS1299 analog front end, organized into non-isolated and isolated domains to protect patients. The post explains why isolation is required, which chips bridge the domains, and why simple, high-level power and signal diagrams help clarify the KiCad schematics for engineers and reviewers.
Getting Started With Zephyr: Using GDB To Fix a Driver Bug
In this blog post, I show how to use GDB to debug an issue encountered with a TSL2591 light sensor driver in Zephyr. The fix was submitted and successfully incorporated into The Zephyr Project.
Unmanned Ground Vehicles - Design Considerations for Snow and Cold Environments
Winter conditions expose UGV weaknesses: snow, ice and extreme cold change traction, sensor performance, batteries and lubrication. This post walks through snow mechanics, ground-pressure tradeoffs for wheels versus tracks, and practical mitigations like heaters, insulation, sensor covers and low-temperature lubricants. If you design autonomous ground systems for cold climates, these engineering checks and referenced studies will help you avoid mission-ending failures.
Practical protection against dust and water (i.e. IP protection)
Needing IP65 protection while exposing humidity and pressure sensors on a tight $15 budget, Dr Cagri Tanriover hunted for a practical fix. He found that an SHT2x humidity sensor with a microporous filter cap and O-ring provides IP67-level protection, and by matching a pressure sensor that fits the same cap he met and exceeded the IP65 requirement. The post shows a low-cost, component-level workaround.
Handling latency in data acquisition systems
In recent projects, I found myself working with data acquisition systems. For instance: PCIe/10GbE readouts for 2D XRay detectors (RASHPA slides, RASHPA paper) instruments mixing 1D signal acquisition and triggering, microcontroller based system for audio transmission: (NRF spearker)
A quick look at the Line Follower Vehicle
A line follower vehicle boils down to four parts: sensors, steering, chassis, and processing. This quick overview explains sensor counts and placement, the tradeoffs between Ackerman and skid-steer steering, and simple processing choices from comparators to an Arduino Uno. Read on for practical tips to pick sensors, arrange the chassis, and avoid common pitfalls when building or tuning a basic LFV.
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.
VERY Fast Japanese Sumo Robots
Japanese sumo robots can be oddly mesmerizing, and this short post captures that perfectly. Stephane Boucher shares a quick reaction to a video and points out the parts embedded engineers would want to hear about, like the sensors, microcontroller, algorithms, and design challenges behind the machine. It is more of a teaser than a teardown, but it makes a strong case for a deeper technical writeup.
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.
