Category Archives: electronics

DIY GSM-enabled Gate Access Control System

I built this system about a year ago, and I get so many people asking me how it was done I figured it would be a good post to help reboot my blog…

DIY Gate Access Control System


Both during the week and on weekends I entertain quite a few guests. We watch TV (sports/movies) in a room separate from the main house (the Playroom* – also home to my workshop) which does not have an intercom extension, and on the summer weekends I host braais in the outside entertainment area (also no intercom extension). Access to the property is through a motorised gate. Often guests ringing the doorbell will be doing so in vain, as the ringing can only be heard from inside the main house. Usually I get a message or a missed-call on my mobile informing me that someone is outside the gate and that no one is answering the doorbell!

Click to find out how I solved this problem using an Arduino, a Cellular Shield, some hardware hacking and some scripting!

SixthSense – A Wearable Gestural Interface


Patti Maes’ Fluid Interfaces Group from the MIT Media Lab have a prototype ‘wearable gestural interface‘ that looks most interesting!

Although the miniaturization of computing devices allows us to carry computers in our pockets, keeping us continually connected to the digital world, there is no link between our digital devices and our interactions with the physical world. Information is confined traditionally on paper or digitally on a screen. SixthSense bridges this gap, bringing intangible, digital information out into the tangible world, and allowing us to interact with this information via natural hand gestures. ‘SixthSense’ frees information from its confines by seamlessly integrating it with reality, and thus making the entire world your computer.

The SixthSense system is comprised of a digital camera, a portable projector and some colour markers. The projector projects an image on to any surface (preferably flat) directly in front of the user. The digital camera tracks the colour markers (typically placed on the user’s fingertips) by sending the images to a mobile computing device in the user’s pocket, which is also responsible for sending information to the projector. In this way gestures traced out by the user are analysed, and the appropriate action or image to display is realised.


For example, the SixthSense system implements a gestural camera that takes photos of the scene the user is looking at by detecting the ‘framing’ gesture. The user can stop by any surface or wall and flick through the photos he/she has taken.

Check out this really interesting video for an overview of the system as well as some application examples:

And you should also check out Pranav Mistry’s (grad student working with Patti Maes) website, for a longer description as well as more pictures and video of the system in action.

SixthSense – Pranav Mistry [via Core77]

The Computer that Got Man to the Moon

SparkFun Electronics have put up a post about a really interesting book on the computer system that helped man reach the moon (the Apollo missions). SparkFun include some excerpts and pictures from the book, so check it out if you’re interested in old school ‘high tech’ hehe. They compare the Apollo computer with a common microcontroller of today – the ATmega168.

Note: The content is directed more towards people with a background in electronics, so those who aren’t forward biased by bipolar junction transistors may not understand everything – BUT the pictures are still pretty ;)

This book is available from The MIT Press as well as Amazon (slightly cheaper).

SparkFun Electronics – Apollo vs Atmel

Eyeborg: Man inserts camera into eye socket

Rob Spence lost his eye in a childhood shooting accident and was given a prosthetic eyeball. Years later he would look at the camera on his cell phone and think: Wow that’s quite a small camera. And then he thought about his prosthetic eye. And then he thought about the camera. The eye. The camera. The e..Th….. HOLEY MOLEY.

Rob is working with engineers to have a wearable prototype ready by next month. That is so crazy cool. Ultimately he wants to film a documentary about privacy and surveillance issues – using the eye-camera .  They won’t even know they’re being filmed (until they’re asked to sign the release).

More info here.

Filmmaker to have ‘Six Million Dollar Man’ camera fitted in eye [via Core77]

score2sms – DIY football score updates via text message

A cool new project I’ve just finished…

Let’s say you’re favourite football team is playing tonight, BUT you’ve just promised your girl that you’d take her out to that new Indo-Cuban sushi restaurant slash hair salon (hey, it could exist). So what do you do? Now obviously you can access the net using your mobile these days, but that means you have to keep checking your phone every 2 minutes. Or I suppose you could ask a friend to update you, but at the rate your friend is downing those beers at the sports bar he’s probably not going to remember to text you (well my friends anyway). The solution?


score2sms is a system using some Linux software, some electronics and an old Nokia mobile phone which will automatically text you when the score changes for games that you have chosen to monitor. Click the pic for more details.

The score2sms setup.

The score2sms setup.

Check out the project page here.