the braille project

Yesterday, I designed a Node-based program to generate a 3D mesh file programmatically from the input text to create a braille message.

Screen Shot 2018-07-03 at 5.22.55 PM

The concept is easy enough to grasp. Braille is a simple combination of raised dots. If we can know that combination, then it should be easy enough to design a 3D CAD object which uses tiny spheres to render the scene.

But I didn’t want to laboriously design this in Autodesk Fusion 360 and I’m sure few people would. Everything has to be precisely placed and that’s just too much manual work. Even if you did, it’s not very easy to maintain. If you did catch an omission, just think of all the work you’d have to do to move things around! I’m relatively certain that this is currently how people create braille-based printouts as seen on an ATM machine, for example.

3d-braille

So yesterday, I designed and created a program for doing this. Generating the STL file was then painless and took less than a second. Printing it then took five hours so I got to see it as a finished part this morning.

IMG_0038

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logistics for the black pearl lcd theme

I decided to add more to the earlier Black Pearl Conky theme for my 3D printer’s TFT screen. It turned out to be a lot easier to do since I’d just finished a new module for OctoPrint.

octo-client:  A node-based module for directly talking to OctoPrint to gather raw information.

octo-conky:  A Conky script for returning that information in a pleasing way.

The new information is there after the “Black Pearl v1.0.1” line where it pulls the version and temperature from the printer.

IMG_0037

j.a.r.v.i.s. realized

If you remember from my earlier post, I wanted to build the cool AI interface from the Iron Man movie series: J.A.R.V.I.S., as voiced by Paul Bettany.

jarvis

Well, I’ve done it. I wrote up several intents in an Amazon Alexa Skill, created an Amazon Lambda function as the end-point, created a proxy in Node (which is served up by a Raspberry Pi Zero W single-board computer) to forward inbound Internet traffic and I’m now able to ask an Amazon Echo Dot how my printer is doing at home.

EchoDot

Remotely Control a Printer

For example, I can say:

Computer, ask Jarvis for my printer’s status.

…to which she will reply:

charming-pascal is ready and operational.

Now remember, I’m two miles away from home while I’m doing this and all of this still works.  I could ask:

Computer, ask Jarvis which file is selected.

…and she’ll say:

RC_microSD-clip.gcode is currently selected.

This is useful to know when I later code this up to remotely print a job as well. I can also ask:

Computer, ask Jarvis for the job status.

…and the reply might be:

charming-pascal is finished printing RC_microSD-clip.gcode

In the collection of skill intents, I now have the following:

  • Stop the print job
  • Start the print job
  • Pause the print job
  • Resume the print job
  • Ask for the print job status
  • Ask for the selected print job file
  • Ask for help
  • Open the Jarvis app

And I’ll need other intents to select a file to print, preheat the extruder and possibly other things yet unimagined.

I’ll definitely want to remotely see the output of the internal webcam inside the printer to make sure that it’s happy; sometimes print jobs go afoul for a variety of reasons.

Remote Power Control

In addition, I also purchased a TP-Link Smart Plug to control power to the printer. I now have an Alexa skill to turn the printer on and off remotely.

tp-link

Computer, turn on my 3D printer.

add comments to a gcode file

I’ve just written a new command-line tool (CLI), this time in NodeJS/JavaScript but as usual, it’s open-source. The program will create a new version of your 3D printer’s GCODE file, adding comments along the way which describe what each command does.

repository

I would suggest that it’s best to install it somewhere in your path and then you should be able to just invoke it easily in your working directory where the GCODE file(s) live:

 

$ gcode-comments file.gcode

;FLAVOR:RepRap
;TIME:11265
;Generated with Cura_SteamEngine 2.3.1
M104 S205            ; Set extruder temperature
M109 S205            ; Set extruder temperature and wait (blocking)
;LAYER_COUNT:28
;LAYER:0
M107                 ; Turn off fan
M205 X10             ; Adjust jerk speed
G1 F2400 E-1         ; Move and/or extrude to the indicated point
...

Input:  file.gcode
Output: file_commented.gcode

the matrix linode’d

Today’s review is about a pretty decent hosting company called Linode. Here’s the three-day timeline from idea to implementation:

  1. Thursday: decided to create a new info website about 3D printing, bought the domain name on GoDaddy and waited for the changes to take effect at midnight
  2. Thursday: created a Github repository to store the source for the website since I’m open-source like that
  3. Thursday: created an account on Linode, purchasing a “linode” for that
  4. Thursday: designed/created the initial local/development website layout/framework, collected images and content
  5. Friday: created (provisioned) the basic linode (virtual machine) for the website on production, provisioned a virtual drive, deployed Ubuntu 16.04LTS onto that, booted and remoted into that, ran updates, installed the framework, added the website, setup security and the firewall
  6. Friday: adjusted the DNS at GoDaddy to point to the new server, added more content
  7. Saturday: launched the website on Linode with the initial version
  8. Saturday: tweaked the settings to make the Node.js—based website start on bootup
  9. Saturday: added more content to the website

site

Not bad for an open-sourced 10-page (44 files) responsive website, if I do say so myself.

Please note that when I say “hosting company”, I really mean a “virtual server provider” so this is more like Amazon EC2 as a service offering. I didn’t just rent website space (like on Wix.com or WordPress.com), I rented an entire virtual server, if you will.

Comparison of virtual server versus website space

There are some advantages/disadvantages of renting a virtual server over just some website slot on a server somewhere:

Pros:

  • In theory, you could run several websites from a virtual server
  • You can run services in the background (like Node.js) and manage them
  • You can run multiple threads on the same server, like helper routines which do something other than serving up pages
  • You’re not limited to the set of templates that are available from Wix.com, for example
  • Your website runs separately from other websites
  • You get an IP address which is only used for your website

Cons:

  • You have to setup security yourself since you’re responsible for the entire server
  • The learning curve is steeper
  • You have to know I.T. things like setting up servers and installing software

Framework/software

Here’s a list of what I used for this website:

  • Node.js: Probably the most famous event-driven JavaScript runtime engine out there
  • Express: A minimalistic Node.js framework for separating code from content on a website
  • Bootstrap.css: A responsive stylesheet and component library for styling a website
  • PM2: A handy process manager for Node-based applications on a server.  After pulling new code, I might run the command pm2 restart AppName to restart the service

Documentation

Kudos to Linode for providing a detailed Getting Started guide along with several tutorial videos on the subject.

And further, a note of thanks to PM2 which seems to satisfy the requirements of bringing up and managing a Node.js application as a service within a production environment and their ample documentation.

Suitability

Is Linode well-suited for most website designers/developers? Probably not. On an I.T. complexity scale from 1 to 10 potatoes, I’d say they’re probably seven potatoes, perhaps. In this case, you’d have to be comfortable doing the following:

  • Using a web-based console to allocate and bring up/down a virtual server
  • Using ssh to remote into your virtual server
  • Navigating within a command line interface on a Linux computer or similar
  • Using ssh-keygen to generate a keypair
  • Using apt-get to update things
  • Editing files using nano
  • Managing services, reading log files
  • Remotely rebooting your virtual server
  • Setting up a firewall, testing and managing same
  • Applying code using git
  • Testing a website to verify that there are no 404 (file not found) type of errors, for example
  • And obviously, creating/designing a website in the first place and using a repository like Github for storing those files

That said, it was a perfect fit for me since I can do those things. In fact, the Linode-related part of this took no more than two hours since this is the first time I’ve used their interface. My next one should go much faster.

Observations

I will say that I’m impressed. Unlike Amazon AWS, Microsoft and Google, the people at Linode haven’t created an interface that’s overly complicated. It seems to work simply and to do the things you need to do and those are: 1) buy a virtual server, 2) deploy something onto it, 3) turn it on and 4) remote into it. I don’t think the “big three” have figured this out yet; their interfaces and the assumed workflow requires too much research, in my humble opinion.

Additionally, the PM2 software does a great job of working with the git-based code distribution model, allowing you to restart the Node.js app when it’s required and to start up automatically each reboot. There’s an easy-to-remember command interface like pm2 show AppName which tells you what you usually want to know.

At a cost of $5/month, it compares favorably to most of the well-known hosting providers out there. The basic linode will likely satisfy the requirements of the average Node.js application up to a reasonable level of simultaneous users, I’d suggest.

price

blinking the raspi’s built-in LED

I’ve just added a repository of some JavaScript code to take over and exercise the built-in activity LED on a Raspberry Pi Zero W (and presumably other models). It’s called gpiozero-toggle-led and it’s a pretty simple interface with installation instructions and some sample code. It works with the underlying js-gpiozero JavaScript port of the popular original Python code. This would be an excellent way of simply demonstrating GPIO without any additional wiring, components, breadboards, extra power supplies or electrical knowledge (like finding a 330-ohm resistor using its color bands).

zero-wireless

Note that the “zero” in the title of the repository and in js-gpiozero does not refer to the Raspberry Pi Zero but to the original gpiozero Python library.

This should remove some of the guess work when attempting to use the relatively-new library since their documentation examples at the moment are taking a back seat to their code port from the more-extensive Python offering.

This approach can easily be modified to instead exercise external LEDs (as soldered or otherwise attached to the header pin locations seen below).  Note that you’ll use “BCM numbering” for APIs such as this one. For external LEDs, you would need to connect it inline with a resistor from a selected pin to one of the grounds for this to work with correct orientation of the LED’s anode/cathode, of course.

raspberry-pi-pinout

If you’re trying to use this with a Raspberry Pi of a different model, you’ll likely want to adjust the JavaScript slightly as seen below.

/routes/index.js:

// Existing code, for a Raspberry Pi Zero
var ledActivity = new LED(47, false);
// For Raspberry Pi 3, for example
var ledActivity = new LED(47);

And that’s it. Since the Raspberry Pi Zero assumes an opposite value for true/false than the bigger models, it’s necessary to configure this in the device constructor to make things work as expected. Since BCM pin 47 is the activity light on the board itself, this will allow you to control it.

how cool is electron?

I’ve been working the past couple of days with Electron, a Node.js cross-platform desktop app tool which uses JavaScript, HTML and CSS to create what look like native OS-style applications for Windows, OS X and Linux.

electron_atomelectron

Cool stuff, indeed. Out-of-the-box, it looks like you publish your Electron-based app like you would anything on github:

git clone https://github.com/Somebody/Repository.git
cd Repository
npm install
npm start

But there’s also a way of downloading OS-specific images and then adding your own app into this subdirectory structure. The result is a stand-alone EXE and folderset which reasonably looks like a drop-in replacement for something you normally would build locally using Microsoft Visual Studio perhaps. In this version though, you’d run Electron.exe but there are instructions on their website for renaming your application, updating the icon’s, etc.

I’ve just used it today to build a basic music player. I wouldn’t say that the layout is as responsive as a typical mobile app’s ability to move content but I did tweak things so that it can squash down to a mini-player and it stills looks great.

mplayer

I can thank KeithIG/museeks for the open-source code behind this. They have several OS-specific downloads available if you don’t want to build this yourself.

Pros

  • This allows you to build cross-platform desktop apps in much the same way that you’d use Adobe PhoneGap, say, to build for mobile apps.
  • You code in the familiar HTML/JavaScript/CSS trilogy of disciplines and it’s Node.js centric. It is also React.js-friendly, as I’m finding on this project.
  • So far, it seems to be well-behaved.
  • If you don’t want others to easily see your code, there’s a step where you can use asar to zip-up everything into a tidy package.
  • I didn’t have to digitally-sign anything like you might have to for a Windows 10 application or for OS X, say.
  • For people who have git and npm, the install is as easy as anything you’ve seen in the open-source space and a familiar workflow.

Cons

  • Currently, I don’t see any support for mobile platforms.
  • The complete foldedset comes in a 216MB which strikes me as a little big for what it’s doing.  The app itself for the music player weighs in at 84MB of this so the remainder is everything that Electron is doing to present all this.
  • You would need to setup three different build sites to maintain a specific download for your own app.  (It’s not like PhoneGap in which you just submit the common code and Adobe builds it in the cloud.)
  • Given that you’re not digitally-signing your code, you might have to talk your users through the hurdles of having the user “trust” the content within their particular OS.
  • This might be so popular soon that none of us can really afford to just use Electron.exe by default to serve up our app; we’ll need to rename it before publishing, in other words.

Overall

I can see myself wanting to really learn this one deeply. It has a lot of potential for delivering a more native-app experience for users.

despicable me—themed supercomputer

I gave a talk on Tuesday to an eager group of 155 attendees at the monthly SanDiego.js meetup on the topic of “Supercomputing in JavaScript”. I had an opportunity to show the new Raspberry Pi 3 supercomputer which I’d built and took it through its paces.

I think they mostly loved the audio events for assembling the minions and sending them to bed (shutting off the remote nodes). There was just enough time to also show the obligatory “Hello, Minions!” demo program to exercise the Message Passing Interface. I received a wide variety of questions and compliments from the group. And of course afterward, everyone who owned a Raspberry Pi came over to discuss their own projects, which was cool.

Here’s the PowerPoint presentation from that talk, in case you’re interested.

e-mc2 repository with step-by-step instructions

open-source minion supercomputer

It seems like every villian these days has their own plan for world domination. So I thought I’d better get started on my own by developing an open-sourced supercomputer design using the affordable Raspberry Pi 3 computer as the basic building block.

Here, I list some of the pertinent points regarding that design.

Minion Theme

The usual master-and-slaves paradigm for most supercomputer systems is replaced here with a gru-and-minions theme. I intend to add sound events at some point in the future, given the usual “headless computer” arrangement for servers. This should help to flag certain events as they’re happening and add some fun to the project as a whole.

Modular

Each squad of four computers would be contained in such a way that it could connect together with the next set of four.  The name for each squad is E=MC2 which stands for Expandable Minion Cube Cluster.

Self-Contained

Each E=MC2 has its own internal Ethernet switch and a USB charging hub to power things inside. The first in the system also includes a shared USB-based thumbdrive for common resources as well as the code that you wish to run in parallel.

Low-Power

Everything internally is powered with a USB charger so that’s about 15W per computer (or core). The power cost then is less than half the per-core cost of a typical supercomputer for electricity, noting that your average supercomputer must also be cooled.

Low-Cost

Weighing in at less-than-$300, the squad of computers has a per-core cost of less than $75. Throughout, I’m using open-source software. I hope to further minimize costs involved by renting time on a 3D printer locally rather than purchasing one.

Mobile

Since I hope to show this project to others, the entire thing should be relatively mobile by design.

In the “known wi-fi” mode, a single power cable could be the only connection to the device, allowing a laptop to connect to it wirelessly. It would be necessary to first educate the gru node and the laptop with the wi-fi credentials, however.

In the “unknown wi-fi” mode, you would add an Ethernet cable to a laptop computer to connect to the system. It would be necessary to configure the laptop’s Ethernet adapter to match that of the internal wired network.

When the 3D printing work has been completed I envision a clear, self-contained, 6″ cube weighing in a under two pounds (minus the power cord). We’ll see how that plays out soon enough.

Technical Savvy

I’m trying to make this as easy as possible for others to repeat. I’m carefully documenting the hardware list to make this easier to source and so that the same set of 3D printing designs I use might accommodate your own attempt at this.

I do, however, assume that you would have some basic electronics experience, have some tools and a small budget to work with and that you understand your way around Linux terminal commands like ls, cp, mv, mkdir, cd, chmod, chown, sudo, apt-get install as well as how to map a drive on a network in either OS X or Windows, say.

You’d also need to know how git and how github works in order to pull the code and design files.

It will be helpful if you understand DNS, DHCP, the concept of IP addresses and how to configure these on a computer.

Documentation in Real-Time

I’ve purchased the new hardware for this, having done some work already preparing the working image for gru, the master node of the system. I’ve created a repository for everything at e-mc2, noting that there are more than one README.md file within the collection of instructions so far.

As I install the full set of software and dependencies again I will be updating the documentation so that everyone may follow along and be assured that I’ve not glossed over any of the details.

Design Hurdles

I had some problems with the first (several) attempts to power everything with a chassis-based switching power supply but the connections themselves proved to be too problematic. And given the open-sourced nature of the project I would hope that others would build their own so I deemed this attempt “too fussy”. Additionally, the “green” Ethernet switch’s tendency to lower its power demands before any nodes came on then confused this power supply which looked something like this:

  1. The “Green” Ethernet switch would power on and the switching power supply would adjust the input current and output power
  2. The switch would determine that none of the nodes had “linked in” to their Ethernet connections (yet)
  3. The switch then would go into green mode and lower its power consumption and the switching power supply then would attempt to toggle down the output power
  4. The switch and other devices wouldn’t get enough power and then would power cycle, repeating the pattern

This next iteration then changes the power system completely which so far promises to be much easier, resulting in solid connections to the devices.

Common Protocols and Code

I’ve decided to use the Message Passing Interface (MPI) for inter-node communications and the Samba software so that the coder may map a drive to the shared data/code area.

Since I like Node.js, I’ll be developing something so that this is a choice as well. The initial “Hello, Gru!” demo may likely be written in Python, however.

Plastic

I’ve found a local place that rents 3D printers. Hopefully I can get some help designing the files necessary to house all this in a clear cube.

As far as external connections/openings to the cube, there should be one rectangular cutout for the IEC320C5 three-prong power plug and a Keystone receptacle for the Ethernet connector so that it can snap into place. Also, there should be some holes adjacent to an internally-mounted speaker. Optionally, there might be openings on both sides if a fan is added. Overall, it should be a pair of clear plastic parts which snap together to form a cube.

Internally, there should be screw holes and possibly slide rails or bumpers for the Ethernet switch, the USB charging hub and the four Raspberry Pi 3 computers. There should be room for five 1′ Ethernet cables as well as five or six 1′ micro-USB cables for power. As preferences go, it should be relatively easy to open up, remove a computer and its micro-SD card for the sake of maintenance, say.

Although it should operate well without a fan, I’m trying to source a usable 5V-powered fan for the design. Since some of you will want to overclock, this is probably a good idea, I’d guess. That being the case, a cube-to-cube side orientation of venting would create a continous flow of air through all. It may be difficult for everyone to source something like a 5V-to-12V boost module but that’s probably the route to go, combining this then with an inexpensive and readily-available 12V computer fan.

Using the Last USB Port Wisely

The existing design calls for four USB cables to power the computers and a fifth to power the Ethernet switch. That leaves one last USB port to power something. Here are some options.

  1. The existing design utilizes a tiny USB thumbdrive which goes directly into the gru node and is shared by all. Instead, this could be a USB-powered external drive with faster throughput, if so desired. One USB cable would connect the drive to gru and the second would provide power over USB to the charging hub.
  2. A small speaker attached to the grunode should allow sound events to be played in conjunction with code execution. Some speakers are USB-powered and this may be an option.
  3. A USB-powered fan would be the logical choice, however, for the remaining port.

Repository

In case you missed the link above, the repository is now at e-mc2 on github. As of today, it’s probably a bit premature to start your own supercomputer from these designs. I personally would wait until I’ve got more of the MPI-based coding in place and have added the step-by-step instructions for some of the dependencies.

Update 3/27/2017

Things are looking great for the repository and the supercomputer itself. The MPI-based code is now working as well as the website for managing the minions.


raspberry pi 3 with node.js

First day with the Raspberry Pi 3 and I’m already having way too much fun with this! Today, I decided to see how fast I could get a Node.js—based webserver running on it and was not disappointed.

Out-of-the-box it comes with the NOOBS installation manager at bootup which politely asks you to install an operating system from the selection. I chose the default Raspian operating system because it’s basically a Debian project and well-trusted.

My task was made simpler because I’d purchased one of the Raspberry Pi 3 kits which included a microSD card pre-loaded with NOOBS. I’d suggest doing the same since the markup over a standard 16GB microSD wasn’t much, to be honest. The empty Raspberry Pi 3 board costs about $35 these days but the kit at $60 includes the NOOBS-preloaded microSD and a 5V power adapter. My kit also included a basic/clear case but I opted for a $9 red case which seems to be more standard.

Setup

For the initial setup, you need spare Ethernet and HDMI-to-DVI cables, USB mouse, USB keyboard and a monitor. Everything gets plugged in before adding the power adapter to boot it.

One thing to note if you’ve just purchased one and are confused, you’ll need to remove the microSD adapter from the included SD adapter before inserting the former into the Pi. They include the larger SD adapter because some people might need that, in theory, to insert it into their workstation if the need arrives. Store the adapter for future use.

microsd

I found that the latest release of Raspian somewhat hides the wi-fi configuration compared to earlier versions. You’ll find what you need by left-mouse clicking the network symbol in the upper taskbar. I also found it necessary to manually edit the /etc/network/interfaces file in a terminal session to change the wi-fi from manual to dhcp. I would imagine that subsequent versions of Raspian will fix this however, you might not be able to easily update the operating system until you’ve achieved a working network connection in the first place.

Headless Boot

Confirming that the networking was happy, I shutdown the Pi, removed everything but the power adapter and booted it again, doing everything next remotely via ssh or RDP.  First I updated the software via a terminal session and then installed tightvncserver, xrdp and samba. I configured a shared drive for use later in /etc/samba/smb.conf file and created a Samba network user for the default pi operating system user. Next, I tested remote connectivity from both a Mac and a Windows-based computer and all looked good for the share.

Next, I installed Node.js globally from a Nodesource.com—based distribution as well as the express-generator. I created a ~/share/sites subfolder and then used Express to generate a new hello application below this. I then started up the newly-created website.  Fortunately, the Samba client recently installed publishes its own hostname to the DHCP server so that I could then surf the website from Windows without knowing its IP address as seen here. The default port for an Express website is 3000, btw.

raspberrypi_webserver

Since I’d created a network share earlier I simply edited the default Express-generated files using Wordpad on my Windows—based computer remotely.

What Next?

From here, I’ll likely be investigating earlier projects like the magnetic card swipe visitor station to convert it to using a Raspberry Pi 3 instead of a larger workstation. By adding a USB-based drive you could likely repeat the earlier Kloudspeaker project with a much smaller footprint.

I intend to create a squad of four Raspberry Pi 3’s in a housing which includes an Ethernet switch, a common power supply and a fan all in a self-contained housing which promotes good airflow and optional stacking. In this case, I’d need to change over to an Ubuntu operating system, I think, since some of the provisioning tools there might make something like this easier. I’ll ultimately have a supercomputer for a fraction of the cost of what you might expect to pay.

In a follow-up post, I’ll be discussing my attempts to install and evaluate the Ubuntu Core for the Raspberry Pi 3 operating system using a second microSD which I purchased for this purpose.