BritishIdeas
Interesting Tech Projects
Tucson to Mount Bigelow Time Lapse
Jun 14th
Last weekend we took a drive from Tucson to the top of Mount Bigelow, which is home to TV and radio antennas. Some stats:
- Driving time – 55 minutes
- Distance – 31 miles
- Altitude gain – 5,500 feet
- Temperature drop – 29 degrees Fahrenheit
- Pictures taken – 1,219
Some things to look for:
- Overexposure in most of the frames. This is because I forgot I left the camera on ISO 800. Don’t do that.
- 0:24 – cyclist
- 0:25 – end of the cactus, start of the small bushes
- 0:29 – fee station
- 0:41 – start of large trees
- 0:50 – Windy Point, a popular vista location to look down on Tucson
- 0:55 – start of the pine trees
- 1:06 – turn off the main road onto a dirt road
- 1:12 – Forest Service truck
- 1:13 – people camping
- 1:16 – a family with a dog
- 1:18 – looking north towards San Manuel, Ariz.
Manual Focus on the Canon A480
Jun 9th
The Canon A480 doesn’t have manual focus of course, but by adding CHDK it does! At first the feature appears to be broken, so here is a short video demonstrating how it works. It’s called Subject Distance Override and to turn it on in record mode press Mode then up (ISO).
It’s amazing how Pinnacle Studio and it’s Dazzle interface can take a nice clean input and make it look like an old VHS tape…
The Big Dipper / Plough
Jun 8th
A total of 105 exposures at 30 seconds each, ISO 400. Canon A480 running CHDK. No in-camera noise reduction. Four dark frames. It took just over an hour to take the pictures.
Google’s Walking Directions – Fail
Jun 8th
I think Google’s software engineers needs to work on their walking directions a bit more. I was playing around and decided to see the walking route from Watford, UK to Plymouth, UK. Here is the result:
Note the warning: “Use caution – This route may be missing sidewalks or pedestrian paths”. Oh yes…
Astrophotography and CHDK
Jun 7th
CHDK is an alternative firmware for many Canon cameras, particularly point and shoot and I previously wrote about it here. One of the nice features is the ability to take continuous pictures for long periods, which makes taking photographs of the night sky possible with a low cost camera.
Here are my first experiments to see what is possible. I am fortunate to live in a place where the light pollution isn’t so bad and there are over 300 sunny days a year.
I set my Canon A480 up to take continuous 30 second exposures pointing roughly north, around 45 degrees above the horizon. I left it for about one and a half hours, during which time it took 155 pictures. I used ISO 80 and the auto focus set to infinity. More >
CHDK and Canon A480 Quick Start Guide
Jun 3rd
CHDK is an alternative firmware for some Canon cameras. It provides access to lots of cool features that are found only on high end SLR cameras, plus some features that are not found anywhere.
Why the Canon A480? Because refurbished cameras are available for $75 from Adorama with a one year warranty and only one version of firmware has been seen on them to date. This means that there is a very good chance the firmware in the A480 you receive will be compatible with CHDK.
This short guide shows how to quickly access some useful features. It is not intended to be exhaustive or replace the CHDK wiki or forums.
CHDK can be set to automatically load when the camera is turned on, however I don’t use that feature because I want to use an 8Gb SD memory card. Cards of 8Gb create complications when autoloading CHDK, but I want the extra space for long time lapse photography.
Download and extract the A480 “full” CHDK zip file from the CHDK website. Extract the files to the top level of your SD card and put the card into your camera. More >
You Tube, H.264, High Definition and FFmpeg
Jun 3rd
Recently I had the need to take a set of jpeg images and convert them into a high definition time lapse video, then upload to You Tube. Easier said than done…
To get the best quality I wanted to use H.264/MP4, which is also recommended by You Tube. I also wanted 1080P. The problem is that You Tube doesn’t seem to like B-frames in the file, and messes up the start of videos. So here is the solution I found.
Firstly I needed to upgrade my Debian server to Squeeze.
Next I compiled x264 and FFmpeg as described in How To Build FFmpeg on Debian Squeeze.
Finally I ran the following FFmpeg command line to generate a time lapse video at 24 frames per second (-r 24), using 1080P (-s hd1080) with no B-frames (-bf 0):
ffmpeg -r 24 -i %04d.jpg -s hd1080 -vcodec libx264 -vpre hq -bf 0 -crf 16 myfile.mp4
It’s important that the frame rate is specified before the input source in order to make FFmpeg apply the frame rate to the source. Note that trying to use qt-faststart causes You Tube to complain about the audio, even though there isn’t any audio.
Crazy Flight Paths
Apr 20th
This is the flight path of British Airways BA84 on April 20th 2010 flying from Vancouver to London Heathrow (from FlightRadar24.com):
British Airways BA84
What happened?
- The flight (Boeing 747) took off from Vancouver while Heathrow was still closed because of ash from the Eyjafjallajokull volcano in Iceland. When it reached the Isle of Man Heathrow was still closed so it was put into a holding pattern for a couple of hours at cruising altitude.
- Other British Airways flights were being diverted to Shannon, Ireland and it looks like the airline and/or ATC gave up and sent the aircraft there, at which point it started descent to 26,000 feet.
- The British Government announced that at 10pm all UK airports would reopen. BA84 then turned back towards Heathrow while over Dublin.
- When the flight reached Birmingham it was put back into a holding pattern, probably because it would have reached Heathrow too early.
- The flight landed at Heathrow at around 9:45pm
Not a flight I would have liked to have been on!
Compiling OpenScales 1.1 with FlashDevelop 3
Feb 7th
This article describes how to compile the OpenScales mapping library for Flash in FlashDevelop 3. OpenScales is an open source LGPL library for displaying interactive maps using Flex and Actionscript. It has many of the features of OpenLayers. FlashDevelop 3 is a free Flash development environment and can be used with the Flex SDK from Adobe.
This article assumes you already have the Flex 3 SDK and FlashDevelop 3 installed and working. See my post from two years ago for help. More >
Rendering of a CNC Machine
Dec 29th
In preparation for a long term project I am working on I created a 3D model of a 3-axis CNC machine in Google Sketchup and rendered it in Kerkythea.
This took quite a bit of tweaking to get exactly the look that I wanted, which is the appearance of the CNC machine inside a large light tent, reducing shadows and a distracting background. I.e. the typical look used for product photos.
CNC Machine
Mechanics of a CNC Machine
