Aug 28 2011

Arduino IR Beam Test

Aaron Hastings

A few of our members recently made a bus walking bus walking trip out to Maplin Electronics here in Galway to source some electronics. A few months ago I purchased a Velleman solder-it-yourself clapper kit, which I subsequently plugged into an Arduino and had some fun with. After picking up some resistors, piezos and other bits n’ bobs, I took another look at the solder-it-yourself section for some inspiration. I came across something which tickled my hackery-fancy, an “IR Light Barrier”, again from Velleman.

The basic principle is the following: Two PCBs, one with the sole purpose of illuminating two IR LEDs, the other having a photo transistor and a fairly large buzzer. Place the two boards across from each other, break the IR “beam” between the IR LEDs and photo transistor and the deafening buzzer starts sounding. Belated apologies to those across the road in John Mulholland.

So in a typical maker reaction, my thoughts were, “Well that sucks”. So I ripped out the buzzer, placed two wires on the PCB contacts and plugged them into my Arduino microcontroller:

What I now have is a brilliantly useful and marvellously simple security system. My next step is to hook up the Arduino code to the Twitter API and have it tweet a message every time the beam is crossed.

INTRUDER ALERT!


Aug 8 2010

Your passwords and you

Mark

lolcat

In the midst of all the preparation for the great Hackerspace events that 091 Labs have coming up in the next week (I’ll be giving a talk on photography and constructing your own camera that you must attend), I want to write down a quick word about the security of your passwords.

Whether it is a desktop or laptop, when you use a computer at the Labs you are using a public machine. We will have old members and new members and the occasional outright stranger dropping in on the Labs to attend our workshops in the coming week. Every one of these folk has as much of an expectation to use these computers as you do. :]

I need to point out that takes a determined person under five minutes to log onto a machine, locate saved sessions and passwords, and record what they find. But thankfully I do not suggest or believe that any member of 091 Labs would act so maliciously.

Instead my biggest concern is potential embarrassment from stemming from inadvertent access to personal or otherwise sensitive information. I have logged into a given computer to find private email accounts left open, Facebook and Twitter account accessible and instant messaging clients left running. I have come home from the Labs at night to find that two people had logged into their Gmail accounts on my laptop over the course of the day.

Two good things for you to do:

  1. Do not save your passwords on an 091 Labs machine. If available, use your browser’s private browsing mode. If you can’t, remember to clear your history at the end of the session.
  2. Use your own computer. That seems to be the majority action right now.

So everyone be careful and have some fun in the coming week!