Projects & Tutorials Archive

Almost three years I published an article detailing how to remotely buzz yourself into an apartment building. In the time since, new technologies have made it even easier to interact with your home remotely. Below, I detail an updated remote door buzzer that works with mobile phones and even Apple Watches. Furthermore, the basic setup is extensible to lighting systems and any other action that can be controlled by a shell script.


The ultimate workflow is simple and is as follows:

  1. On your smartphone or Apple Watch, send a Yo to a custom-created recipient
  2. Your door buzzer will be activated

To achieve this, we’ll be using a custom-made circuit that electronically switches the door buzzer. To control the circuit remotely, we’ll be using a Raspberry Pi home server that will receive casually authenticated signals over the internet sent via the Yo app (

Required Gear

The following items will be used to create your phone-controlled door buzzer:

  • Raspberry Pi — Any Raspberry Pi model should work, but I’m using the Raspberry Pi Model B+. You’ll also need an SD card (micro SD in the case of the B+ model) with at least a few gigs of space, and all gear


I’m a newly minted Pebble owner — going on three days. As the novelty of receiving SMS and e-mail on my wrist becomes my new normal, I’ve been looking for more ways to use the device. Sitting in Starbucks only one hour ago, it occurred to me that I could replicate Starbucks’ digital payment method currently enabled by iOS Passbook (and its native app) on the Pebble e-watch. All I needed was enough real estate to show the barcode with sufficient resolution that the reader would pick it up. Apparently the Pebble has enough real estate even on its tiny 168×144 screen, and I have just bought my first drink paid for with my Pebble.

This being my first Pebble app, what follows is horribly ugly.

I knew that I wanted to use a watch face as a template. Pebble treats “watch faces” different than “watch apps” — the most important distinction being that you can access watch faces from the home watch view simply by hitting the up or down keys and scrolling through them. Watch apps (like calculators or games) are accessed through the selection button, then you scroll through all your app


While the world is all aflutter about viewing tasks and news alerts from a wristwatch, I’ve recently discovered two delightful programs that allow me to do the same from a terminal window — yes, without a mouse.

Task Warrior

Task Warrior is an impressively fully-featured terminal task list manager.  After a quick review of the tutorial, I was up and running with powerful task customization capabilities beyond those even offered by Google’s task client.  Task Warrior supports not only project-categorization and due dates, but also dependencies, recurrence, project completion progress, and more.  Furthermore, the entire application is extensible via third party or custom scripts and add-ons.

Tasks are easy to add with simple syntax such as follows:

$ task add Call home
$ task add Pick up milk proj:Errands pri:H
$ task add Walk the dog due:eoy recur:daily proj:Life tag:dog

Also, the developers have smartly added three levels of task-viewing: very short, short, and complete (below). Also, it’s easy to view only specific projects as your task list grows. The simplicity is addicting, and will never be maligned as skeuomorphic. I’m eagerly awaiting future versions of the client which will allow syncing across devices.

Task Warrior: 3 views

…which is to say I don’t.

In the realm of contemporary touch-free interface, RFID and NFC are probably 95% of the pie. They are widely adopted in building access control, contactless payments, mobile-to-mobile sharing, supply chain management, and even hospital patient tracking. For these purposes they are remarkably inexpensive to install and maintain, and the technology is mature. Given these benefits, it is not unreasonable that one should want the convenience of contactless access control without the key fob, chip, or smartphone, and so a small community of DIY RFID-implanters has come into existence.

The notion of implanting an RFID tag is not wholly unreasonable (no so different than many other types of mainstream (implants) and alternative (piercings, tattoos, etc.) invasive body modifications). After all, my two dogs have painlessly carried an RFID chip in the skin between their shoulder blades for years now (for non-pet owners: this is a common practice to allow identification of lost pets). Such purpose-build tags are biologically inert and as RFID does not require a local power source, they do not contain any harmful chemicals and do not radiate unless scanned — they are just a little glass, plastic, metal,


The Guardian recently published an article arguing that overly-frequent consumption of “news” is bad for us: it misleads, increases cognitive errors, and may actually make us less healthy by constantly sparking our flight-fight responses.

Regardless of whether we’re slowly killing ourselves with news, it resonated with me because I realize that my consumption of news is bordering on obsessive, or at least it’s what I turn to first when I’m bored and find myself viewing the same landing-pages over and over mindlessly. Even if there is fresh content to entertain me, I can’t remember the last time The Huffington Post actually added value to my life. At the very least blocking these sites will improve my productivity. Consequently, I devised an easy tool to block news sites at the click of a button, and to turn them off again with another click.


By customizing your Windows-machine’s HOSTS file, you can block websites temporarily without any third party software. The file that maps web hostnames to IP addresses. Hostnames are the textual identifiers of network devices, for instance you can name a printer on your network ‘speedy’ or you can access a website at the host name ‘’. Websites’ hostnames


You can lead a horse to water, but you can’t make it drink. While the world drools in anticipation of the Pebble or an Apple or Samsung smartwatch, Nike is sitting idly by fielding a promising piece of tech on the JV team while it could be a runaway hit in the big leagues. I speak of the Nike Fuelband, the wristband with a white and RGB variable-brightness LED output, accelerometers, an input button, Bluetooth and USB interface, iOS interactivity, and a four-day battery life in a well-designed water-resistant package with three color options (see teardown here).

I’d be pretty excited if had that tech on hand to sell. It could alert me to and read txts and e-mails, it could give me some basic gesture input to an app, it could show caller id, etc… basically what the Pebble proposes to do, even if in a more spare LED graphical output. Nike has not only refused to market the product as a mobile-connected wearable output device, but it has actively opposed others’ attempts to liberate the device for such purposes. And so you get what we had here last week, which is the way they wants it:


Google Glass is a head-mounted display that supports augmented reality output; sends and receives calls, txt messages and e-mails; gives directions; serves as a headphone and is capable of recording and playing back video.

The first six consumers who will receive a Glass were announced yesterday morning, followed by 8,000 others. They won the opportunity to buy a Glass (for $1,500) by saying what they would do with it on Twitter (tag #ifihadglass). Of those first six, only one is proposing to use Glass in a meaningful way for which it uniquely-suited versus existing, much cheaper tech. Max Wood is proposing to use Glass to stream building layouts, objectives, and orders to fire fighters, and capture their streams for incident commanders. That would make use of the head-mounted display (HMD) overlays, audio output, wireless communication, and video-capture features – hopefully saving lives through it. Four of the others are proposing to use Glass exclusively as a poor man’s (read: rich man’s for $1,500) POV camcorder or VR-display. The last is proposing to use it as a voice-transcribing platform.

Lucky human camcorder #1: Wants to give a first-person view of life


There is a new version of this tutorial available. Check it out here!

I could carry my keys to unlock my building door, but I’d rather not. I could buzz up to my apartment and my girlfriend could buzz me in if she’s around, but that’s obnoxious. It would be best if I could buzz up a short-code to my apartment (a Morse message of sorts) and have it automatically buzz me in. Fortunately, that can be done with Arduino.

The Buzzer Situation

My apartment building is equipped with a Aiphone VC-K intercom and door release system. The entire system runs on 12V DC power with low current, so it’s much safer to interact with than any devices attached to a wall outlet. A quick web search for the model yielded a wiring diagram, a screwdriver provided quick access to the terminals in the handset unit, and a multimeter allowed me to understand how it works:

Aiphone wiring diagram

I have access to the VC-K unit in my apartment; the VC-M is at the front door. Terminals 1 and 2 provide communication with the


Across the internets I’ve found two prominent methods for using an iPad as a graphics tablet in cases without native application support (like Photoshop CS5/6). Both rely on third party apps to stretch your desktop display onto your iPad, but by slightly different approaches. Neither solution will provide the pressure or pen-angle detection that Wacom tablets provide, and their input resolutions are comparatively poor. However, if you’re just hoping to make some simple hand-drawn paths in Illustrator or the like, these are fine solutions.

Considering the factors below, I find LogMeIn to be a much better tablet input solution than Air Display. Both are imperfect, but LogMeIn came out on top.

LogMeIn Free Edition

LogMeIn a remote desktop control service that let’s you control a remote computer from any web browser or an iOS app. Both the service and the related software are free. The premium versions provide more advanced functionality like web-printing but for our and most other purposes the free version is perfect. Although you can use the program from a coffee shop to access your desktop, you can also use it while sitting right in front of your desktop as a tablet input device. You retain full control of


I knew all that time spent playing Call of Duty on Wii would pay off. The newest issue of Make Magazine (#33) offers an interesting and relatively easy project that turns a Wii Nunchuk into a gesture-based computer input device. Now I can be just as much of a deadeye in Excel – C2, bam; F7, bam – but at least in Excel everyone’s a winner. The guide was written by Gabriel Bianconi, an impressive Brazilian teenager, who appears to have been working on the project for a few years now.

The project pairs a Nunchuk with an Arduino to provide serial input interpreted by a custom Arduino library and a straight-forward Python script available on Make’s website that drives mouse events via win32api.  Best of all, the project is non-destructive – Wii Nunchuks accept regular jumper wires so you can try the project at no cost (assuming you already have an Arduino and Nunchuck), and later disconnect the controller for gaming use at any time.

The web link to Make’s online tutorial appears to broken at this time, but you can refer to Gabriel’s original tutorial if you can’t find a hard copy.  For further reading, check out this guide detailing the