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The Linker

28 posts
Written by Elecia White.   The first thing that most people do when getting a new board is to blink an LED. Embedded engineers treat it as though it is the simplest, most basic operation. We call it “hello world” to show how friendly and software-similar it is.   Blinking an LED implies a working cross compiler and a programming tool, not your run of the mill high-level software concepts at all. Sure, a software developer may have a compiler (or at least an interpreter) b ...
Written by Elecia White.   I mentioned earlier how I was looking at different internet platforms for my mice overlords. The goal is to design an internet connected mouse feeding system that a high school student could build from off-the-shelf parts. I’ve been trying to figure out the base platform and came up with two options: the ESP8266-based SparkFun Thing and the Cortex-M3/Broadcom based Particle.io Photon.   Electric Imp probably should have been in consideration as well b ...
Written by Elecia White.   In Part 1, I started to take apart by BB8 droid. In Part 2, I took a close look at the hardware. Now, let’s see what I can discover about the software. Remember, I don't work for Sphero and I don’t usually take apart my toys so reverse engineering is new to me. But it is really, really fun.   I didn't expect for this to be such a great tool to explain some interesting embedded software concepts. But before we get to that, let’s look at t ...
chriswhite

Cheating on Tests

Posted by chriswhite Sep 22, 2015
Written by Elecia White.   Have you heard about the VW diesel emissions scandal? The software detects that the car is being tested for emissions and changes the engine to function more cleanly. When not being tested, the vehicles do not meet the US Environmental Protection Agency’s emission requirements.[1]   I’m incensed at this. Oh, not because I own a VW (I don’t) or because I’m an environmentalist (I am). I’m angry because there is an embedded softwa ...
Written by Elecia White.   In Part 1, I left you with a puzzle: given the chip markings what can you tell about the BB8's internals? I've done very little reverse engineering before so this was quite a challenging.   There are a few SMD databases and the eevblog forum is a good site for package translation. Typing random numbers and letters into a search engine leads to strange, occasionally useful results. It was a try-everything sort of time (and ask anyone who might possibly k ...
Written by Elecia White.   I gave a talk last week at the SupplyFrame/Hackaday metetup. It was supposed to be a reprise of my introduction to inertial sensors that I wrote about here a few months ago.   However, when my order for a pair of the Star Wars BB8 robots came, I decided I’d rather talk about a specific application of inertial sensors instead of the theory and math. (Chris got co-credit for the talk because he did a lot of exploration with me as well as taking the pi ...
Written by Elecia White. I have a client project where they made a device with an Arduino UNO, datalogging shield, small display, photo interrupter, and a motor driver controlling a stepper. When a mouse takes a pellet of food, the photo interrupter’s IR beam is no longer blocked so the system wakes up, moves the motor, and logs the date and time to an SD card. They wanted to make it lower power so it would last for 10 days on their 5V 11Ah battery. They also wanted to keep it reasonabl ...
Written by Elecia White.   We have all heard that so-and-so was meant to be an engineer because they took things apart as a child. I wasn’t like that. If I took things apart, it was more in a smashing fashion. And, they never went back together (sorry, Mom).   The first time I remember reverse engineering something was in college, freshman or sophomore year. An engineer from Mattel visited, bringing Barbie dolls and razor blades. We dissected the dolls and really looked at the ...
chriswhite

Error Handling

Posted by chriswhite Aug 25, 2015
Written by Elecia White.   On Episode 112 (My Brain Is My Resource), Chris and I briefly answered a listener question about how to handle errors. Our response went something along the lines of “bubble errors up to wherever the system is intelligent enough to handle them.”   This answer was not very actionable and the question of effective error handling is a good one so we dug into it more on Episode 114 with Andrei Chichak (Wild While Loops). Let’s start with some ...
chriswhite

Conference Musings

Posted by chriswhite Aug 19, 2015
Written by Elecia White. I recently attended a conference I wasn’t happy with. It got me to thinking about conferences, why I attend them, and what I want out of future ones.   I primarily attend conferences to learn things and to meet people. The things I want to learn fall into four groups: Learn something in more depth than I can get from an online video or article (but not in so much depth as a book) Acquire new ideas, one I’ve never seen before, such as new technology ...
This post was written by chriswhite.   Last time, I gave an intro to the Photon IoT development board, but didn’t have enough time to get into the details of the project I was making. This week I’ll get into the details.   Despite my outward skepticism about the Internet of Things, I somehow end up as an early adopter for many IoT products. I have the Phillips Hue lights, a Nest thermostat, a Netatmo weather station. Oh, and I had a Lockitron. The Lockitron was (and is, in ...
Written by Elecia White. I am not a security expert. I am not a cryptographer. I do care, perhaps slightly more than average, how my device data can be used maliciously. Possibly, it is because I am a developer and can think of all the slimy ways I could misuse someone else’s data were I to put down the white hat and put on a black one. We invited Jen Costillo on Embedded.fm as she’s discussing ethics and wearables at the Silicon Valley Embedded Systems Conference (ESC) this mon ...
I’m terrible at personal projects. Let’s just get that out of the way. I have a collection of neglected hobbies, half (or less) finished electronics builds, unprocessed astrophotos, and unfinished song ideas leaving a wake behind me. Sometimes a project falls by the wayside due to attention span, but usually what happens is that I run into some obstacle that convinces me the idea will require much more time or effort than anticipated. And in the pile it goes. Yet, as I mentioned on o ...
chriswhite

Brave New Hello World

Posted by chriswhite Jun 30, 2015
Written by Elecia White.   At O’Reilly’s Solid conference, I presented an introduction to using inertial sensors. In the talk, I passed around a hardware demonstration to illuminate accelerometers, angular rate sensors, and magnetometers.   The device is "hello world" for inertial sensors so I keep rebuilding the code for different processors and inertial measurement units (IMUs). The platform I want to show today is a Freescale Freedom KL05Z (FRDM-KL05Z) with a sensor to ...
Written by Elecia White.   On episode 104, we talked to Andreas Eieland of Atmel about choosing low power processors, comparing them with EEMBC’s benchmark ULPBench, and tips for achieving low power. If you are making a low power device (like a wearable), you need to understand how to minimize current draw to maximize battery life. However, even before that you have to know how to measure current. After all, why optimize something that takes a microsecond when you draw a lot more to ...