Friday, April 17, 2015
This page: http://bikealive.nl/sd-v2-initialization.html
Was indispensable for me recently when trying to figure out why I could not read an SD card. It turned out that an on-board regulator for one of my parts was expecting 5 Volts, so when supplied with 3.3 Volts, it was supplying ~2.3 Volts to the SD card, and it was not operating reliably. Once I told the SD card to operate on 2.7-3.3V, it would stop responding.
I placed a serial print statement in my low-level "spi-send-byte" function that printed the byte transmitted and the byte received, and it let me follow along the initialization sequence outlined in the above link and see where things went screwy.
Saturday, April 11, 2015
US Income tax filings are due on April 15th for the prior year. My income for Anibit sales is not organized in a way the makes it easy to come up with a net taxable income, so I have to manually pour over all sales for last year to come up with the proper figures. The worst part of it is that while I have the cost basis (ie, the part of gross sales that were not profit) data, I don't have an easy way to collate it, so I'm going to have to wear out the numpad on my computer with a bunch of spreadsheets. All of this will actually amount to a very small amount for Uncle Sam. Anibit's sales last year were nothing to write home about (more on that in a future post). I just really need to avoid overpaying what I owe, which is what would happen if I don't comb through all the sales.
This could possible be avoided if my Anibit's software had a little more in the way of reporting tools, but I understand it's a very hard thing to do since you can't really make a blanket formula for how tax accounting should work.
Thursday, April 9, 2015
- Price: Runs in the neighborhood of $10 USD
- Wifi b/g/n, reportedly up to 54MBps
- On-board chip antenna, and UFL connector for an optional external antenna
- Included STM32F205 ARM Cortex-M3 120MHz CPU with 128kb SRAM and 1Mb of Flash
- About 20 available IO pins (+2 on board LEDs, and JTAG/SWD breakout)
- Uses Broadcom Wifi chipset, compatible (after some finagling) with their WICED sdk
- Broadcom has a lot of support for "IoT" in their SDK, with appliance samples, Access Point setup, and embedded web server support.
- Mostly (but not all!) 5V tolerant I/O pins. (I love that, level shifters are such a pain)
- Documentation for the device itself, is almost non-existent.
- You must rely on the documentation for the constituent parts, and the work of some industrious hackers, see this.
- If you can read Chinese, you may have better luck.
- It's not straightforward on how to use it as simply a Wifi adapter for an external Microcontroller. I believe there are firmwares for this, but it will require a lot of research.
- 2.00 mm pitch headers on the breakout. Who does this, seriously! I think MxChip must have hired the person who came up with the XBee socket.
- The various SDK and libraries are a slight licensing minefield. If you want to use this for a closed source or proprietary application, read through all the licenses of all the sub-parts carefully. There are some "free for closed source commercial" library license options, but not all of them are.
- 2 15-pin 2.54mm (0.1") pitch male headers for the breadboard part.
- 2 15-pin 2.00mm pitch male headers for the EMW3162 module, unless you already have them mounted.
- 2 15-pin 2.00 pitch female headers to receive the EMW3162 on the adapter.
Comparison to ESP8266
Resources to get you started
- Several folks have started an analysis as a Hackaday project, and they're adapting their own flavor of the WICED sdk for use with the board.
- The WICED SDK, which includes an Eclipse/CDT tailored to embedded devices using Broadcom chipsets.
- The Github Repo for the WICED fork specific to this board.
- Seeed studio sells a couple Development boards you can plug your 3162 into. This one has a JTAG port for an external JTAG, and this one has an on board JTAG built in.
- My breadboard adapter you can order in multiples of 3 for $8 per set (you'll need to find the headers separately)
Wednesday, March 11, 2015
- Inspect the internals of the function foo, to learn all of it's expectations of the passed in type
- Read documentation bequeathed by the author(s) of foo
- run a "lint" -type tool for static analysis to catch improper usage.
- run the code and debug the exception that gets thrown when you pass it an invalid object.
The second aspect to Web Development that makes me marvel at it's popularity is way in which user interfaces are created, the DOM. Creating user interfaces in html is for the self-taught an execise in cooking "div soup". Go to any major modern website; Facebook, Twitter, CNN, and open the page in the dev tools in your browser off choice. Invariably, it's built with nested div upon div upon div's. The css is typically where the magic happens that makes those div actually look and behave like the site you're visiting. But it's a dark art to getting it right and authoring, that comes with experience, not necessarily the good kind. It takes years of learning the arcane quirks like "oh you need to wrap that in a div with float:left" or "oh Firefox need's explicit widths on those elements". Compared to most of the Desktop UI frameworks I've worked with, traditional web UI development feels .... irrational.
There is hope though, I think things are getting better. HTML 5 has enabled the tools needed to make vast improvements. A lot of HTML 5 is not implemented yet, and even more is still experimental or bleeding edge. Web Components offers a path to maybe one day doing away with the div soup and making a more satisfying meal. I have been experimenting with Google Polymer lately, and it's still very new, but has me excited that I might soon be able to build a browser app with markup that makes sense for a UI.
[Note, I struggled to find the right title for this post, no offense to millennial engineers is meant by it. I think if you learned how to program before Google was a thing, you cut your teeth under a different set of common wisdoms than today. Some are now obsolete but others got lost to the noise of the new shiny. The merit of strong explicit contracts seems like one of those lost wisdoms these days. I'm always keeping up with the new shiny, while trying not to loose touch with my roots. Millenials are crazy-smart and talented. Now get off my lawn!]
Thursday, January 8, 2015
Sometimes, libraries, native dlls, or environment in your Windows application's running process can interfere with each other. 'Pure' .Net managed code is much less prone to conflict due to .Net's fantastic versioning, type system, strong naming, and separation via application domains. In real world applications, you often need to interact with a lot on native code or APIs where you have no such protection. This blog post is about a simple way to keep native dependencies separate for different code within a single .Net desktop application.
I found that when I had the browser loaded, the GeckoFx library, that is a managed shim for Mozilla's "xulrunner" embedded Firefox, that when I spawned the compiler as a child-process, it would fail with a lot of cryptic errors. If I did not load the browser component, the spawned compiler worked fine. I'm pretty sure that some dll's or environment settings or something in the process's memory were not playing well between xulrunner and gcc. Rather than spend forever tracking down the exact problem, which I ultimately probably would have had to build my own xulrunner or gcc binaries to fix, (yuck), I came up with a nice work-around that gives me the best of both worlds.
On start-up in my application, before I have done anything, I launch a second instance of the application with special command-line parameters. The parameters tell the second instance that it should run in a "remote execution server" mode, and I also pass the Windows process ID of the parent to the server/child. The child process periodically checks to see if the parent process is still running, and exits if not.
The child process starts a server for a ".Net remoting" object. .Net remoting is one of lesser-known/understood technologies of .Net, but it's fantastic if you're on a pure Microsoft technology stack. It makes remote procedure calls across applications or even machines super simple. Essentially, with some small configuration files, and a little bit of support code, you can create a class who's functions automatically get executed in the child process. The calls can be synchronous, and parameters and return values are magically handled by the CLR. (Note that Microsoft advises against using the 'legacy' remoting APIs, and instead recommends using "Windows Communication Foundation". I find for really simple situations, .Net remoting is a bit simpler to setup and use, and the remote interface is dynamically generated so there's no endpoint API to maintain.)
Rather than make a lot of diagrams or posting code to this blog, I just put a small demonstration C# project on Github, if this sounds like it could help you, feel free to use it for whatever you want. You can find it here.
Tuesday, December 23, 2014
I've got a lot of polish to do on the html itself, but I finally got it to a minimally viable web app.
Check it out: https://anibit.com/box
Friday, December 12, 2014
The group holds 2 hour meetings, and in the first hour, people are invited to present things they've worked on, If you're convenient to the Raleigh area, and can make it to NC State's campus on the second Monday evening of the month, you should check it out! It's a great group of people.
At last week's meeting, I gave a brief talk about my "Automated CAD design" post. Pete Soper, one of the founder's and organizers of the group, was kind enough to edit and post the video of my talk to Youtube. If you've read my post, I don't have much new information in the talk, but I do say "um" a lot. (I have a secret podcast I've been working on, and I probably would have published it by now if I could stop saying the u-word so much).
Anyways, thanks Pete!
Sunday, December 7, 2014
Friday, November 21, 2014
I received a lot of positive feedback on my last post, and some of the ideas posted on the sites that picked it up gave me the inspiration to write this follow up. There were some good ideas and some questions posed so I thought I'd try to make few addenda and clarifications.
Choice of toolchain.
I chose OpenSCAD mostly as the first thing that popped into my head. The nightly version (2014.03 as I write), is fairly stable. The output it generated was well received by most of the other tools I used it with, which included Blender3D, for rendering the preview images, MeshLab for debugging the geometry when I goofed something, and LibreCAD for loading the 2D DXF files to send to my laser cutter. I even used Elmer to do some rudimentary(and probably naive) stress sanity checks.
I did lament that some the really cool features in the bleeding edge version of OpenSCAD were not available, but the generated output of the newer version had some erroneous geometry. I've read on the OpenSCAD forums there may be some versions for download that don't have those bugs.
I had worked with OpenSCAD before, so I knew what it's capabilities and limitations were. I wasn't really tied to OpenSCAD, here are some alternative tools work very similarly. Ultimately, it came down to the devil I knew, and that it supported all of the features that were critical to me: easy to setup, mature and stable, bug free STL and DXF output, and allowing me to programmatically override the skeleton designs by emitting generated design code.
Wednesday, November 19, 2014
First, I should get something off my chest, the title is probably a little misleading. "Heavily parameterized 3D case design" might have been a more accurate, but dull title.
I recently kicked off laser cutting services on Anibit, and I plan to augment that service with a lot of specific product designs that I create. I'm a nut for automation and flexibility, and I'm deficient in intrinsic artistic talent. I determined that, as much as possible, I would design the physical aspects of my mechatronics creations in a way that I could easily make changes large and small, and not have to re-do much work.
My first area of focus was an
|Automatically rendered preview image.|
Wednesday, October 8, 2014
Last week, I ended my employment at my "day job", to work full time on Anibit.com and building a consulting business. It's very exciting, and I'll admit, a little scary. I'm going to be adding a lot of services to Anibit.com (and I'll add a "hire me" sidebar pane to this blog soon).
It's been a dream of mine to run my own company for a long time. I'm not getting any younger, and I plan to die with no regret for something I never got around to. The timing for me personally is as close to perfect as it gets, which is to say not really perfect, but pretty good.
I've also always wanted to do pod-casting and video production. I've started a daily podcast, but I'm in "practice mode" right now, because I need to work on my "radio voice"(I say 'um' in between every other sentence). I've also played around with producing some screencast tutorials, also not ready for prime time. I'm also now in "fail fast" mode on Kickstarter project that I've been cultivating for 6 months in what little free time I had. I'll go public with those details soon.
Wish me luck in these exciting times, expect to see more frequent updates here, and on Anibit's website. And if you have any Windows desktop, Android, or AVR/ARM cotrex applications you would like developed, give me a shout at anibit.technology[at symbol]gmail[dot symbol]com
Monday, September 29, 2014
One thing to watch out for is that the maximum stable clock speed for an AVR is reduced when running at lower voltages. ATtiny85s cannot run reliably at the internal pll'ed clock speed of 16MHz, when powered at 3.3 volts. I've cried myself to sleep over this, so I offer this cautionary tale. Read your datasheets!
Tuesday, September 23, 2014
I'm having some issues with my new domain for this blog, so I've temporarily reverted it to the old bytecruft.blogspot.com domain. Atom feeds may or may not be working and please disregard any wierd redirect warnings ove rthe next few days while I work it out.
Working in Raspian Wheezy, you have a lot of Debian Linux at your disposal, so I thought, "I'll just ssh in" That works great, from either a Linux VM, or using Putty on Windows. I needed to run graphical applications and spawn terminals at will, so I really wanted full desktop experience.
X11, the base graphic interface run by virtually all Unix-like operating systems, supports a feature known as display redirection. I used this back in the 90's when I tried to make use of a boat anchor DECstation from my Slackware Linux box. It still pretty much works the same way it did 20 years ago. Before I get too far into how it works, I'm just going to stop and and mention that if all you want is to remotely run graphical programs on your Rasberry Pi, stop right there! There is a much easier way! X11's server-client model is very powerful and flexible, and is unique in a class of technologies that has stood the test of time, but it's not very "get'er done" user friendly.
Linux machines support Microsoft's "Remote Desktop" protocol with two programs: xrdp and rdesktop.
xrdp is the "Remote Server". This runs on the machine that your want to remotely log into. Note that is this backward from X11, where the "server" is the machine with the physical display, and the client is the (remote) application that generates contents to display.
To install xrdp on your Pi (if using Raspian or other Debian Linux derivative), type:
sudo apt-get update
sudo apt-get install xrdp
You're pal apt will download, setup, and launch the xrdp deamon to start listing for connection requests. If you're parnoid, reboot your Pi to make sure.
Tuesday, August 26, 2014
The tl;dr version is: leave your RAM alone, let the operating system manage it. Teams of people smarter than you and I have figured this problem out.
How paging files work.
Mental experiment: a femto computer:
Monday, August 18, 2014
I swear by Oden, I shall return to this blog in full strength.
I'm pretty sure that you'll run into issues if you use anything but the latest browsers, I didn't do any testing of old browsers, and probably will always target the latest stable browsers.
I wrote a calculator tool for determining the target address for an AVR microcontroller relative jump instruction. The motivation was personal, I've spent a lot of time recently staring at hex dumps from AtTiny devices, I wrote a bootloader (more on that in a future post), and debugging it involved memory dumps of a lot of dynamically generated rjmp instructions. (AtTiny device do not have hardware support for bootloaders, so you have to fake it in software). I got tired of calculating it by hand, so I wrote a spreadsheet, and thought, "If I could write it in a web app, it would be there forever, and I'd always have access to it".
Check it out at:
Friday, May 16, 2014
Thursday, May 8, 2014
I've been pretty much head-down, working on things related to Anibit. I think some more of it will be public soon.
So the title of this post, is my Public Service Announcement about ATtinys. FMUL is Atmel's assembly instruction for "unsigned fractional multiply". Before you make grandiose plans that hinge on doing fast math in hardware, make sure your CPU supports it. Most, if not all, ATtinys do not support hardware multiplication.
Thursday, March 13, 2014
I have to say one stark lesson I've already learned is "Just because you've built it, doesn't mean they'll come". I have very little traffic to my site, and website traffic generation ranks substantially below marketing in requisite business development activities as far as my interests go. I know there are thousands or tens of thousands of people out there that would be interested in the site, but how do I connect with them? Part of building a catalog of existing parts was to attract a regular audience/demographic interested in hobby electronics. That, and other content I have planned (in the next phase, starting soon) would make Anibit bookmark/Feedly-subscription-worthy site.
But I get the feeling, given metrics to date, that there's more needed that just throwing content up and hoping for people to find it. Yet, I don't know what that thing is. My traffic to Anibit so far is dismal, especially if you cull the traffic generated by my personal Social Networking friends(lot of my hits cluster in places I or my family have lived). I supposed I should keep it in perspective (starting a business requires a healthy does of that). Self-bootstrapping with cash on hand like I am doing requires a lot of patience, and the experiences I've had while doing it so far have almost all been rewarding and overwhelmingly positive.
Tuesday, February 25, 2014
This is a reflow oven controller:
My oven controller is coming along, in between doing a lot of behind the scenes work on Anibit.com.