We all know that hacker that won’t use a regular compiler. If he’s not using assembly language, he uses a compiler he wrote. If you don’t know him, maybe it is you! If you really don’t know one, then meet these two. [Nathan Fuller] and [Andy Baldwin] want to encourage you to write your own 3D slicer.
Their post is very detailed and uses Autodesk Dynamo as a graphical programming language. However, the details aren’t really specific to Dynamo. It is like a compiler. You sort of know what it must be doing, but until you’ve seen one taken apart, there are a lot of subtleties you probably wouldn’t think of right away if you were building one from scratch.
Continue reading “DIY 3D Slicer is a Dynamo”
We’re used to the relationship between the commercial software companies from whom we’ve bought whichever of the programs we use on our computers, and ourselves as end users. We pay them money, and they give us a licence to use the software. We then go away and do our work on it, create our Microsoft Word documents or whatever, and those are our work, to do whatever we want with.
There are plenty of arguments against this arrangement from the world of free software, indeed many of us choose to heed them and run open source alternatives to the paid-for packages or operating systems. But for the majority of individuals and organisations the commercial model is how they consume software. Pay for the product, use it for whatever you want.
What might happen were that commercial model to change? For instance, if the output of your commercial software retained some ownership on the part of the developer, so for example maybe a word processor company could legally prevent you opening a document in anything but their word processor or viewer. It sounds rather unreasonable, and maybe even far-fetched, but there is an interesting case in California’s Ninth Circuit court that could make that a possibility. Continue reading “Will Your CAD Software Company Own Your Files, Too?”
Forth has a strong following among embedded developers. There are a couple of reasons for that. Almost any computer can run Forth, even very small CPUs that would be a poor candidate for running programs written in C, much less host a full-blown development environment. At its core, Forth is very simple. Parse a word, look the word up in a dictionary. The dictionary either points to some machine language code or some more Forth words. Arguments and other things are generally carried on a stack. A lot of higher-level Forth constructs can be expressed in Forth, so if your Forth system reaches a certain level of maturity, it can suddenly become very powerful if you have enough memory to absorb those definitions.
If you want to experiment with Forth, you probably want to start learning it on a PC. There are several you can install, including gForth (the GNU offering). But sometimes that’s a barrier to have to install some complex software just to kick the tires on a system.
Continue reading “Browsing Forth”
Jenkins is open-source automation software that tries to automate parts of the software development process. When you submit code, for example, Jenkins will grab it, build the project with it and run any tests on it. If you have a large number of people submitting new code or data, Jenkins will wait and grab a bunch of the submissions to build. Depending on the size of the project, this can take a while, and if there’s a problem, you need to know quickly so that people aren’t waiting on a broken build. Email’s fine for this, but [dkt01] saw one of the desktop LED Christmas tree projects on Hackaday, and integrated it into his Jenkins system.
Like the other projects, WS2812b LED rings are used as the tree, and an Arduino Pro Mini runs the show, with an Ethernet LAN Module to communicate with the Python script that monitors the Jenkins build job. The Python script sends commands to the Arduino, which in turn lights up the LEDs. They light up green on a successful build and red if something fails, but during the build process, the LEDs show the current state of the build, tracking Jenkins’ progress as it builds.
Our previous Jenkins post used a big, red LED light that would light up if the build failed. [dkt01]’s build lets you know if the build is successful or has failed, but the build progress is a great addition.
Continue reading “Jenkins Lights the Christmas Tree”
I have a confession to make. I enjoy the challenge of squeezing software into a tiny space or trying to cut a few more cycles out of a loop. It is like an intricate puzzle. Today, of course, there isn’t nearly as much call for that as there used to be. Today even a “small” microcontroller has a ton of memory and resources.
Even so, there’s still a few cases where you need to squeeze those last few bytes out of memory. Maybe you are trying to maximize memory available for some purpose. Maybe you are anticipating mass production and you are using the smallest microcontroller you can find. Or maybe you’re doing the 1 kB Challenge and just want some advice.
One way to find techniques to maximize resources is to look at what people did “in the old days.” Digital Equipment computers once had a special character set called Squoze (or sometimes DEC Radix-50). This technique can be useful when you need to get a lot of strings into memory. The good news is that you can reliably get 3 characters into 2 bytes (or, as DEC did, 6 characters into 4 bytes). The bad news is that you have to pick a limited character set that you can use. However, that’s not always a big problem.
Continue reading “Squoze Your Data”
When you have a large software development team working on a project, monitoring the build server is an important part of the process. When a message comes in from your build servers, you need to take time away from what you’re doing to make sure the build’s not broken and, if it’s broken because of something you did, you have to stop what you’re doing, start fixing it and let people know that you’re on it.
[ridingintraffic]’s team uses Jenkins to automatically build their project and if there’s a problem, it sends a message to a Slack channel. This means the team needs to be monitoring the Slack channel, which can lead to some delays. [ridingintraffic] wanted immediate knowledge of a build problem, so with some software, IoT hardware, and a rotating hazard warning light, the team now gets a visible message that there’s a build problem.
An Adafruit Huzzah ESP8266 board is used as the controller, connected to some RF controlled power outlets via a 434MHz radio module. To prototype the system, [ridingintraffic] used an Arduino hooked up to one of the RF modules to sniff out the codes for turning the power outlets on and off from their remotes. With the codes in hand, work on the Huzzah board began.
An MQTT broker is used to let the Huzzah know when there’s been a build failure. If there is, the Huzzah turns the light beacon on via the power outlets. A bot running on the Slack channel listens for a message from one of the developers saying that problem is being worked on, and when it gets it, it sends the MQTT broker a message to turn the beacon off.
There’s also some separation between the internal network, the Huzzahs, and the Slack server on the internet, and [ridingintraffic] goes over the methods used to communicate between the layers in a more detailed blog post. Now, the developers in [ridingintraffic]’s office don’t need to be glued to the Slack channel, they will not miss the beacon when it signals to start panicking!
I’ve had the fortune or misfortune of interviewing a lot of job candidates over the years. It amazes me how often someone will claim to know something, sound reasonable, but then if you quiz them on it, it becomes really obvious that they don’t know much. To flush this out, we had a three-question test that would tell you a lot. People who got the right answer were ahead of the game, of course, but even looking at how people approached the answer (right or wrong) would tell you a lot, too.
I remember one case where the answer involved casting a value. A candidate had impressed me until faced with the question to which he said (more or less): “Well, there’s this function. I think it is called ‘cast’…” I think the look on my face told him that I actually knew the answer (not surprising, since I was giving the test) and that wasn’t it.
[Oleksandr Kaleniuk] has a C quiz of only five simple questions. They reminded me of at least one of my old company’s three-question quiz. I don’t want to say too much about the character of the test because I don’t want to give away the answers, but if you think you are a C wizard, go check it out. Then come back in the comments and tell us how you did. Just try to avoid posting spoilers (although you should probably avoid the comment section until you come back).
Continue reading “Think You Know C? Find Out”