19hertz

ramblings of an electronic engineer.


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Tweed Heads ‘Frog Beach’

Tweed Heads is one of the places I have always had fond memories of. As a child my family used to holiday down there once a year which was typically spend swimming, kite flying, reading, playing board games and going for walks just before or after dinner. Of the beaches there are three main ones: Duranbah Beach, Rainbow Bay/Snapper Rocks and what my family called ‘Frog Beach’ due to the large green rock painted like a frog. So one Sunday I realised how long it had been since I had been there and went for a drive to do have lunch down there, create a timelapse and read. This timelapse was a bit of an experiment. I used my Hoya ND400 to decrease the amount of light coming into my camera to about 1/500 of the original light which allowed me to get exposures of around 2 seconds in broad daylight (when stopped down to f8) This means that the waves, people and clouds are blurred according to how much they move and as far the the final timelapse is concerned things look and transition a lot smoother. So after some level adjustments and editing here is the final timelapse.


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Q1 and Gold Coast Timelapses

A few weeks ago i did two timelapses, the first is taken from lower beechmont and features the expanse of the Gold Coast skyline. The second is up Q1 again trying out my Tokina 11-16mm wide angle lens and a technique to block out reflections from the glass (which I will cover in a future post).


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Fingal Heads Trip

Last Friday night I went down to Fingal Heads, NSW with some friends (Peter, Matt and Ben) to do a lightpainting collaboration. Anyhow here are some of the photos shot on my camera.

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Afterwards we decided to take two timelapses while we were there to finish of the night.

This first one if from my camera,

and the one from peters camera

And just for good measure a stacked photo of the timelapse,

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For more photos of the collab check out my friend peters flickr page.


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7 Eleven Bottomless Cup Day 2013

Last year I wrote about 7 Eleven’s BYO cup day and what the maximum amount of slurpee you could expect to get for your purchase.  Well this year 7 Eleven is having another one day promotion where you can purchase a large cup of slurpee and refill it throughout the day for free. So I thought I’d go about calculating how again the maximum amount of slurpee you could expect to get. The way I was going to calculate this is to make an estimate on the amount of time it would take you to fill, pay and consume a slurpee, however I realised that that would have too many variables and would be pretty hard to calculate for an ‘average person’. So Instead I decided to take the same approach I used previously to calculate how much chocolate it would take to kill you. So pretty much this article won’t calculate the maximum amount of slurpee you could get but the maximum amount you would “want to get”?

“All things are poison, and nothing is without poison; only the dose permits something not to be poisonous.” – Paracelsus

Anyhow lets go,

So while we don’t actually have toxicity levels of water for humans, we do for rats which is what we shall be working off. So from water’s MSDS we find that water has a LD50 of 90ml/kg in rats, thus for an average human

90ml*70kg = 6.3 litres

Now considering the large cup size is 650ml,

6.3/0.65 = 9.69 large cups.

So there you go, anymore the about 9 cups could potentially be deadly, these calculations are very rough (any possible wrong) and do not take into account individual physiologies etc…

TLDR: Don’t drink more than 9 large cups of slurpee in one sitting.

**This article should not constitute as medical advice, use the information within at your own peril etc…**

As a bonus I thought I’d try creating a timelapse of me working on something namely this post.


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Perseids Meteor Shower 2013

Over the past month or so I’ve been taking quite a few timelapse’s so for the next two months I shall be releasing one a week and talking a little about it. I’d love you to let me know what you like, dislike and how I can improve.

This timelapse was taken during the Perseids meteor shower and once again like my previous attempts of timelapses’s during meteor showers I didn’t manage to capture any meteors D: anyway this timelapse was taken over an hour period or so with 10 second exposures. It had to be cut down by a few seconds since nearing the end the lens started to fog up (something I now know how to fix but probably won’t get around to going for a while.)

As always I recommend watching in 1080p fullscreen 🙂


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Death by chocolate

Since today in International Chocolate Day… how much chocolate would it take to kill you? In general most people know that you shouldn’t feed chocolate to dogs because it can make them sick and in some cases die (actually cats are even more sensitive to it however they have no sweet receptors on their tongue so are less likely to ingest a lethal dose). This is because a compound called theobromine which is a toxin found in the chocolate. The lethal dosage to have a 50% chance of death (known as the LD50) of theobromine in dogs if around 300mg/kg of weight, and 1000mg/kg of body weight in humans. Know this we can calculate how much theobromine is required to have a 50% chance of death… Lets start with a dog

Average Weight = 25kg; LD50 = 300mg/kg = 7.5g

And now for a human…

Average Weight = 70kg; LD50 = 1000mg/kg = 70g

Different chocolate has different amounts of theobromine but for these calculation lets say that for every 470g of milk chocolate there is 1g of theobromine and for every 140g of dark chocolate there is 1g of theobromine. Factoring this in we find that to have a 50% chance of killing a dog it must consume either 3.5kg of milk chocolate or 1kg of dark chocolate, and for humans 32.9kg of milk chocolate or 9.8kg dark chocolate.  However remembering this is only the LD50, there also exists a LD (low) which is the minimum amount of a toxin it can potentially take to kill a subject, which in the case of theobromine for dogs is 16mg/kg body weight and humans 26mg/kg. Redoing the maths we find the the minimum amount of chocolate required to potentially kill a dog is around 188g of milk chocolate or 91g of dark chocolate. Finally for a human 855.4g of milk chocolate or 254.8 of dark chocolate is potentially deadly.

TL;DR Don’t eat more than 250g of dark chocolate or 800g of milk chocolate in one sitting.

Edit: This article should not constitute as medical advice, use the information within at your own peril etc…