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Archive for March 2009

Automatic Garage Doors and Infrared Tripwires

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I like things that make life easier. One of the first things we installed when we first moved into our house was an automatic garage door. Getting out of the car to open the garage door in the rain is for chumps!

Knowing when to close the garage door is tricky.  We had been guesstimating by using a chalk mark on the wall, but that’s fairly inaccurate – the car bumper has been scratched by a closing garage door on more than one occasion (mostly by me). The solution would to install something that can tell when the car is fully in the garage. And the first solution I thought of (me being an engineer) was an infrared tripwire.

An infrared tripwire works by shining a beam of light at a sensor across an open space. When a solid object disrupts the light beam, such as a car or a person, it triggers an alarm of some sort – usually a buzzer or light. Shops often use infrared tripwires to detect patrons entering or exiting the store.

There are a few ready-made tripwires available on the market, ranging from $100-$150, but I found this kit at Jaycar (the Kemo B216N “Infrared Light Barrier 5m”) that apparently does the same thing for only $15 (plus around $30 for housing and connectors) – just need to solder it together. No sweat. The guys at Jaycar in Maddington also threw in a 12v power supply in for free. Thanks guys – free stuff good 🙂

Dusting off my soldering iron, I assembled the kit over a few nights. It took about 2 hours in total to solder in and test all the components. It didn’t work straight away so I gave it to my dad, the electronics engineer, to diagnose. He found that the instructions had capacitors C8 and C9 switched around, a fact that is obvious once I looked more closely at the photo. It took about another hour or so to prepare the cabling and housing.


When I finally tested the tripwire, it worked great – at night time. During the day it didn’t work at all, as its sensor couldn’t tell the difference between the its tiny infrared LED and the sun. It was particularly bad in the afternoon, when the sun shines directly into the garage. Curse you big flaming ball of infrared energy!

I needed another solution. After a lot of blasphemous remarks about sun-related deities (and words rhyming with “trucking”), I settled on a kit that was cheap, quick and easy to install, accurate to the millimetre and works in all light conditions:

A feature comparison between the Kemo kit and the tennis-ball-hanging-from-the-ceiling kit:


Infrared Tripwire




$0 (recyclable components)

 Construction time

3 hours

3 minutes

 Installation time

1 hour

15 minutes







 Works during the day?




Sometimes the simple solutions are the best ones.


Written by Richard

26 March, 2009 at 10:11 pm

Posted in tech

How to Kick Vocal Ass on Rock Band

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In a recent podcast, Hamish & Andy shared a small insight into the male psyche:

Love the Beast” isn’t about a car – it’s a film about how guys need an activity to bond with each other.  It has nothing to do with not being in touch with each other or not being able to communicate properly, it’s just a guy thing that we need something to do so that we can chat to each other when we are doing stuff.

For me, that male-bonding activity is Rock Band.  Every few weeks, a few of my ex-colleagues get together to rock out on plastic instruments, earn fake money and amass a small colony of virtual fans.  From the outside, it just looks like four geeks on toy instruments.  But from the inside, it is pure Rock & Roll – escapism at its finest.

Maybe it’s because the othersare mostly IT types (or maybe I’m just a mic hog), but I tend to be on vocals a lot of the time.  That’s not to say I am a stellar singer –  anyone unlucky enough to have heard me sing before know this (an asthmatic cat is a good analogy).  However, over the years I have learnt a few tips on how to score big as the vocalist:

1. It’s all about Pitch. All that matters is that your voice follows the melody.  If you don’t know the song, just hum it and track your pitch using the indicator.  If the song or a particular section is too high for you, drop an octave. The game won’t know the difference, but your voicebox will thank you for it.

2. You don’t have to hold every note. Watch the clock in the top-left corner under the lyrics. It ticks over when you are singing within the pitch range for each bar. Once it’s full, you can stop – there’s no need to keep going with the rest of the bar. Save your vocal stamina for the rest of the song.  (Note that Guitar Hero World Tour doesn’t have this meter.  Boo!)

3. Save your overdrive. Once your yellow bar under the lyrics is over half full, the game will give you opportunities to kick into overdrive (the score multiplier).  Don’t use it immediately – save it for when your other band members have activated their overdrive for full effect. This normally means waiting for the drummer to activate his overdrive, as he has less opportunities to kick it in than you do.

4. Avoid Metallica. Their songs hurt, and are rediculously un-fun on drums anyway.  If you must get your Hetfield fix, save it for the end of the night when you no longer need your vocal cords.  While you are at it, why not drink more beer just to finish them off for good.

If you’re an amateur like me, you’ll probably find your vocal range and volume gets worse throughout the night.  I asked an old friend, a professional singer for more than a decade, how she manages to gig through the night week after week.  Here’s what she said:

1. Never sing when you’re dehydrated.  If you reckon you’ll be singing at any point in the day, drink lots of water beforehand.

2. Always warm up your voice and warm down. A good exercise is to take a deep breath and pretend you’re blowing raspberries in the air but with one long sustained note. This one takes practice. It forces you to use your diaphragm to release your voice. The longer your raspberry goes, the more engaged your diaphragm is.

3. NEVER EVER sing outside of your range. If you feel like you’re belting a note and it’s ‘hurting’…. stop. Singing should never hurt.

4. Never ever sing out of breath. Always remember to breathe. The number of times I’ve hurt myself coz I forgot to breathe before I sang is incredible. Taking a breath makes all the difference. Make sure you don’t scream from your throat. That’s a sure fire way of losing your voice in a hurry!

5. In between sets, I try NOT to talk. Rest your vocal chords as much as you can.

Sound advice indeed. It works – I drink lots of water during the day and warm up in the car on the way to the gig (despite strange looks from passing motorists).  My voice is still weak at the end of a 6-hour session, but hey, that’s the Rockin’ lifestyle for ya.  Rock And Roll!

Written by Richard

19 March, 2009 at 7:19 pm

Posted in Uncategorized

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Burn, Damn You Calories, Burn

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Cateye Velo 8Ever wondered how bike computers, steppers, treadmills, etc. calculated the Calories Burned from just your speed and travel time?  Neither did I, until I discovered that my new bike computer said that I only burned around 290 calories per day riding to and from work – the equivalent of one thigh piece of KFC. Surely I was burning up more than that, right??

The textbook method of calculating calories burned looks something like this:

Calories burned = ((METs * 3.5 * weight in kg) / 200) * duration

There are a few things that stood out when I saw this.  Firstly, MET stands for Metabolic Equivalent of Task, which is essentially the amount of heat produced by the body when exercising, and can be fudged in part by using the average speed.  Fair enough.  However, the formula also requires my weight, which the computer doesn’t know.   What other assumptions must it be making?

I emailed Cateye to find out from the source.  To my surprise I got an answer, and within 24 hours (kudos to Cateye for actually responding!).  Here’s what they said:

Thank you for your inquiry.  As you mentioned, since the calorie counter of the Velo 8 model is not adjustable for age, weight nor fitness level, it is an estimate calculated from an “average” cyclists data, and is usually accurate for most users to within 10%.

“Average cyclist”? “Most users”? “Within 10%”? Really?

To test this, I googled and found this online calorie calculator, which conjures up the magic number by activity, weight and duration.  Punching in my figures gave me this:


132% more than what the computer said.  I am obviously not what Cateye consider “most users” or “average cyclist” (which I find hard to believe).  After a bit of trial and error, I came to the conclusion that Cateye’s “average cyclist”  must be around 72kg and cycles at a “leisurely” pace (of around 3.7 METs, approximately half the METs of cyclist going at 12-14mph):


So I was burning up more energy than I thought I was.  Hardly definitive proof, I know, but still.

The moral of the story is: don’t believe everything your trip computer tells you.  Or rather, if you google hard enough you can find facts to justify anything.  As for me, it’s a 2 piece feed for lunch tomorrow …

Written by Richard

12 March, 2009 at 9:58 pm

Posted in exercise

The Best: Buttermilk Pancakes

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Genna's Buttermilk Pancakes

I love pancakes – nothing beats a thick stack of warm fluffy pancakes topped maple syrup on a Saturday morning.  I’ve tried a few different recipies in the past and this recipe is the best one by far.  It is dead-easy to make and the results are soft and fluffy – just how pancakes should be.  

The kids love it with Nutella, and the wife’s favourite is Philadelphia cream cheese and strawberry jam.  I like them with ice cream, but that’s not allowed when the kids are awake.

The recipe is reproduced here in case bestrecipies.com disappears. 

Buttermilk Pancakes 

Recipe :31 
Serves: 10
Preparation time: 15 minutes or less 
Delicious with maple syrup and whipped cream.
  1. 1.25 cups plain flour 
  2. 1 teaspoon bicarbonate of soda 
  3. 1 heaped teaspoon baking powder 
  4. 0.25 cup sugar 
  5. 0.25 cup sunflower oil 
  6. 1 egg 
  7. 400 mL buttermilk 
  8. Salt 
  1. Sift flour, bicarbonate of soda and baking powder into a mixing bowl. 
  2. Add sugar, egg, oil, buttermilk and a pinch of salt.
  3. Blend together with a hand mixer until smooth.
  4. Melt some butter or margarine in a frying pan over medium heat.  
  5. When pan is hot, pour batter into pan to form a circle about 10-15 cm in diameter. 
  6. Pancake is ready to flip when bubbles form and pop on the upper surface. Underside should be golden-brown in colour. 
  7. Flip and cook the other side until brown. 
A few tips and tricks:

Teddybear Pancake


  • Feeding 10 is a little ambitious.  Our family of 4 can polish off a whole batch no problems.
  • The easiest way to add the buttermilk without using another container is to put the mixing bowl on a weighing machine, tare it off and pour in 400 grams of buttermilk).
  • Let the mixture sit for at least 10 mins for best results.  The buttermilk needs time to react with the baking powder to create bubbles (which, incidentally, are carbon dioxide).
  • I use a 2-tablespoon ladle to get the batter in the pan.  That helps make them all the same size and cook at the same rate.
  • A flat, electric frypan works better than a skillet over a gas stove, as it’s easier to control the heat.  I set mine at 150c.
  • For extra fun-ness, make teddy bear-shaped ones by using two small dollops for ears.  Kids under 3 love them 🙂

Written by Richard

9 March, 2009 at 8:14 pm

Posted in food