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Sensors Expo - Trip Report & My Best Video Yet!

Stephane Boucher August 3, 20183 comments

This was my first time at Sensors Expo and my second time in Silicon Valley and I must say I had a great time.  

Before I share with you what I find to be, by far, my best 'highlights' video yet for a conference/trade show, let me try to entertain you with a few anecdotes from this trip.  If you are not interested by my stories or maybe don't have the extra minutes needed to read them, please feel free to skip to the end of this blog post to watch the...


R1C1R2C2: The Two-Pole Passive RC Filter

Jason Sachs July 28, 20181 comment

I keep running into this circuit every year or two, and need to do the same old calculations, which are kind of tiring. So I figured I’d just write up an article and then I can look it up the next time.

This is a two-pole passive RC filter. Doesn’t work as well as an LC filter or an active filter, but it is cheap. We’re going to find out a couple of things about its transfer function.

First let’s find out the transfer function of this circuit:

Not very...


Linear Feedback Shift Registers for the Uninitiated, Part XVII: Reverse-Engineering the CRC

Jason Sachs July 7, 20181 comment

Last time, we continued a discussion about error detection and correction by covering Reed-Solomon encoding. I was going to move on to another topic, but then there was this post on Reddit asking how to determine unknown CRC parameters:

I am seeking to reverse engineer an 8-bit CRC. I don’t know the generator code that’s used, but can lay my hands on any number of output sequences given an input sequence.

This is something I call the “unknown oracle”...


Making a connection 1

Ed Nutter July 3, 20182 comments

In order for your system to control devices, you must be able to connect it to those devices.

Besides different sizes based on wire size, there are a few different styles of connectors that can be used.  There are also weather-resistant terminals that can be used if needed.

Ring

(Parks, 16)

- used for circuits that you don’t want to become easily disconnected

- ground wire attached to a stud

Push-On

- can be used on relay terminals

(Parks, 18)

- could be...


Linear Feedback Shift Registers for the Uninitiated, Part XVI: Reed-Solomon Error Correction

Jason Sachs June 19, 2018

Last time, we talked about error correction and detection, covering some basics like Hamming distance, CRCs, and Hamming codes. If you are new to this topic, I would strongly suggest going back to read that article before this one.

This time we are going to cover Reed-Solomon codes. (I had meant to cover this topic in Part XV, but the article was getting to be too long, so I’ve split it roughly in half.) These are one of the workhorses of error-correction, and they are used in...


Troubleshooting notes from days past, TTL, Linear

Ed Nutter June 19, 20181 comment

General Troubleshooting

  • Follow safety precautions.
  • Always think “what if”.
    • Analytical procedures
    • Precautions when probing equipment
    • Insulate all but last 1/8” of probe tip
  • Learn from mistakes
  • Don’t start with electronic test equipment, start with analytical thinking.
  • If you get stuck, sleep on it.
  • Many problems have simple solutions.
  • Whenever possible, try to substitute a working unit.
  • Don’t blindly trust test instruments.
  • Coincidences do happen, but are relatively...

Linear Feedback Shift Registers for the Uninitiated, Part XV: Error Detection and Correction

Jason Sachs June 12, 2018

Last time, we talked about Gold codes, a specially-constructed set of pseudorandom bit sequences (PRBS) with low mutual cross-correlation, which are used in many spread-spectrum communications systems, including the Global Positioning System.

This time we are wading into the field of error detection and correction, in particular CRCs and Hamming codes.

Ernie, You Have a Banana in Your Ear

I have had a really really tough time writing this article. I like the...


Tenderfoot: How to Write a Great Bug Report

Matthew Eshleman May 31, 20184 comments

I am an odd sort of person. Why? Because I love a well written and descriptive bug report. I love a case that includes clear and easy to follow reproduction steps. I love a written bug report that includes all the necessary information on versions, configurations, connections and other system details. Why? Because I believe in efficiency. I believe that as an engineer I have a duty to generate value to my employer or customer. Great bug reports are one part of our collective never-ending...


Who else is going to Sensors Expo in San Jose? Looking for roommate(s)!

Stephane Boucher May 29, 20186 comments

This will be my first time attending this show and I must say that I am excited. I am bringing with me my cameras and other video equipment with the intention to capture as much footage as possible and produce a (hopefully) fun to watch 'highlights' video. I will also try to film as many demos as possible and share them with you.

I enjoy going to shows like this one as it gives me the opportunity to get out of my home-office (from where I manage and run the *Related sites) and actually...


Voltage - A Close Look

Ralph Morrison May 23, 201811 comments

My first boss liked to pose the following problem when interviewing a new engineer.  “Imagine two boxes on a table one with a battery the other with a light.  Assume there is no detectable voltage drop in the connecting leads and the leads cannot be broken.  How would you determine which box has the light?  Drilling a hole is not allowed.”

The answer is simple. You need a voltmeter to tell the electric field direction and a small compass to tell the magnetic field...


Scorchers, Part 3: Bare-Metal Concurrency With Double-Buffering and the Revolving Fireplace

Jason Sachs July 25, 20201 comment

This is a short article about one technique for communicating between asynchronous processes on bare-metal embedded systems.

Q: Why did the multithreaded chicken cross the road?

A: to To other side. get the

— Jason Whittington

There are many reasons why concurrency is


Continuous Integration for Embedded Systems

Tayyar GUZEL September 5, 20172 comments

It is no secret that anyone who wants to streamline project management, reduce risk and improve the quality needs some form of "automation" in SW development processes. What is commonly used in most companies as a tool for such automation is called Continuous Integration (CI). It is a good practice for embedded systems as well even though it is much harder to use CI for embedded systems compared to pure software development because embedded systems mostly depend on...


The DSP Online Conference - Right Around the Corner!

Stephane Boucher September 20, 20201 comment

It is Sunday night as I write this blog post with a few days to go before the virtual doors of the very first DSP Online Conference open..

It all started with a post in the DSPRelated forum about three months ago.  We had just had a blast running the 2020 Embedded Online Conference and we thought it could be fun to organize a smaller event dedicated to the DSP community.  So my goal with the post in the forum was to see if...


Mutex vs. Semaphores – Part 2: The Mutex & Mutual Exclusion Problems

Niall Cooling May 15, 20197 comments

Part 1 of this series we looked at the history of the binary and counting semaphore, and then went on to discuss some of the associated problem areas. In this posting I aim to show how a different RTOS construct, the mutex, may overcome some, if not all, of these weaknesses.

To address the problems associated with semaphore, a new concept was developed during the late 1980’s. I have struggled to find it’s first clear definition, but the major use of the term mutex (another...


You Will Make Mistakes

Jason Sachs September 28, 20141 comment
</scorpion>: FAIL

Anyone out there see the TV pilot of Scorpion? Genius hacker squad meets Homeland Security in a fast-paced thriller to save hundreds of airplanes from crashing after LAX air traffic control software upgrade fails and they didn’t save a backup of the old version (ZOMG!!!) so thousands of people are going to die because the planes… well, they just can’t land! They just can’t. Even if the weather is sunny and calm and there could quite possibly...


Ada 2012 for ARM M3/M4 Released for Download

Mike Silva August 4, 201413 comments
Previous Ada Tutorials

Ada 2012 Comes to ARM Cortex M3/M4

It's Here!

Great news - AdaCore now has their initial ARM Ada port available on their download site.  You can get it by going to http://libre.adacore.com/download/ and working your way to the page titled "Download GNAT GPL and SPARK GPL Editions".  There, under "Select Configurations" you will see ARM ELF for Linux and for Windows.  Those are the ones you want.

Porting the Ada...


Data Types for Control & DSP

Tim Wescott April 26, 20166 comments

There's a lot of information out there on what data types to use for digital signal processing, but there's also a lot of confusion, so the topic bears repeating.

I recently posted an entry on PID control. In that article I glossed over the data types used by showing "double" in all of my example code.  Numerically, this should work for most control problems, but it can be an extravagant use of processor resources.  There ought to be a better way to determine what precision you need...


Wye Delta Tee Pi: Observations on Three-Terminal Networks

Jason Sachs December 23, 2018

Today I’m going to talk a little bit about three-terminal linear passive networks. These generally come in two flavors, wye and delta.

Why Wye?

The town of Why, Arizona has a strange name that comes from the shape of the original road junction of Arizona State Highways 85 and 86, which was shaped like the letter Y. This is no longer the case, because the state highway department reconfigured the intersection


Sensors Expo - Trip Report & My Best Video Yet!

Stephane Boucher August 3, 20183 comments

This was my first time at Sensors Expo and my second time in Silicon Valley and I must say I had a great time.  

Before I share with you what I find to be, by far, my best 'highlights' video yet for a conference/trade show, let me try to entertain you with a few anecdotes from this trip.  If you are not interested by my stories or maybe don't have the extra minutes needed to read them, please feel free to skip to the end of this blog post to watch the...


Trust, but Verify: Examining the Output of an Embedded Compiler

Jason Sachs September 27, 2015

I work with motor control firmware on the Microchip dsPIC33 series of microcontrollers. The vast majority of that firmware is written in C, with only a few percent in assembly. And I got to thinking recently: I programmed in C and C++ on an Intel PC from roughly 1991 to 2009. But I don’t remember ever working with x86 assembly code. Not once. Not even reading it. Which seems odd. I do that all the time with embedded firmware. And I think you should too. Before I say why, here are...