PaulSeward.com
Finding his photographic feet, one photo at a time
‘ave a Bluenana!
I had a distinct lack of ideas for this weeks photo challenge. So I decided to take a photo of something yellow, and invert the colourspace to get blue. To get the blue bananas I copied the base layer, inverted it, then set the blend mode on the new layer to “colour” (which preserves the white highlight and black shadows)
Apart from a little sharpening after the resize, that’s pretty much all I did. I quite like the result. Even if it is a little more “gimmicky” than my usual fayre.
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BoB Juggling Festival, and when Juggling meets Phones
This is Jon Peat, British Young Juggler Of The Year 2006, probably one of the most interesting ball jugglers I’ve seen in a long time. He was trying out a new routine on stage at the BoB Juggling Festival this weekend. There are some more photos from the show in this album here.
However, the most productive part of the day for me, was my chat to Tarim about my idea for a telephone based siteswap validator.
The Background:
For those that don’t know, siteswap is a mathematical language for describing juggling patterns. The idea is that you can use a string of numbers to represent the pattern. Each number represents a throw event, with the number determining how many beats later the object is thrown again. Eg a 3 means that the object being thrown at that time, is next thrown 3 beats later.
Some strings of numbers are valid juggling patterns, for example 531 (which is a 3 object pattern) but not all strings are valid. For example, 540 is not a valid siteswap, as the 5 object is next thrown in 5 beats time, but the 4 is next thrown in 4 beats time. This means that they’re both thrown by the same hand at the same time. There’s a collision.
There’s a lot more to siteswap than that, if you’re interested in all the gory details start here with this wikipeida article about siteswap.
It’s handy some times to be able to check if a string of digits is a valid juggling pattern or not, telephone dials have digits, so they can be used as an input device. They also have earpieces, so can be used as an output device.
The Plan:
To build a device which you can plug an old rotary dial phone into, which allows you to do the following.
- Pick up handset
- Listen for a dialing tone
- Dial in the siteswap you want to validate
- Hang up handset
- Wait a few seconds
- The phone will then ring
- When you answer the phone, a recorded message plays telling you if the number you dialed is a valid siteswap or not.
I had a firm idea about how to do all those steps apart from step 7, getting a microcontroler to play speech isn’t trivial. Talking to Tarim though gave me an idea of how to get around that though by using a cheap MP3 player. Result!
I’ve built a circuit which interfaces to the phone line, and can detect hook state and count dial pulses. I can get audio onto the phone line. I know *how* to make the phone ring, but am lacking the components to do so.
In short, I’m *soo* close!
Posted in Experiments, Phones, Photos | 2 Comments »
GPO Ring Cadence generation
As I’m sure you all know, British phones ring in the following cadence: “0.4sec on, 0.2 sec off, 0.4sec on, 2sec off” – which is the one true timing for telephone ringing as far as I’m concerned. The USA do some kind of “2 seconds on, 4 seconds off” thing which is easier to generate, but really not very nice to listen to on a lovely GPO phone (My trimphone sounds especially “wrong” with the American cadence)
Anyway, we’ve been scratching our heads about how to make a relay click in the right cadence, to switch the ringing current in the telephone exchange we’re building.
Last week, I sat down with my “Big Book Of 555 Timer Tricks” and sketched out the above circuit – but didn’t have enough of the right component values to build it. Ian did have enough junk components in the right ballpark, so built it at the weekend. And it works! Rah! He’s got video of LEDs flashing and everything!
The circuit uses two 555 timer chips running in Astable configurations, one generating a slow waveform which is used to turn on and off a second timer, which generates a faster waveform. The upshot is that you get short bursts of the faster waveform at the output. The on/off timings are written on the diagram, and are chosen so that you get two “on” pulses from the second timer in the time it takes the first timer to turn on. Bingo, GPO ring cadence FTW!
The interesting(?) bits of this are that the second timer is turned on/off using its reset pin, and that the first timer uses a diode to give a duty cycle of less than 50% – the fun bits are that my phones can now go “rng ring” instead of “ring”
Posted in Experiments, Phones | 6 Comments »
The Beginning?
Well, I’ve had a week off – and you know what? I miss the whole photo-a-day thing. Or at least, I miss having something to think about on the way to/from work, in the tea room, and all that.
So. I have a plan!
52 projects, in 52 weeks.
2009 is to be the year that I finish all those little things I started work on. It’s going to be the year that I build the “RS232 over tin-cans-and-string” thing, the year I build that ring flash out of disposable cameras, the year that I build a small scale AM transmitter so that I can tune the valve radio in my kitchen to the 1950s…
The rules:
- I have 52 weeks to complete 52 projects.
- Photos will be taken, build notes will be written up, software will be published.
- While I aim to average a project a week, completing two projects in a week then taking a week off is allowable
- Progress will be reported when it’s available, even if the project is as yet unfinished.
I’ll be maintaining a page which lists (and numbers) the projects, with links to the blog articles describing progress. Wish me luck!
Posted in 52 Projects, Experiments | 10 Comments »
Pop!
I’ve been playing with my cheap-as-possible-sound-activated-flash-trigger again.
After ripping through a whole packet of balloons trying to get the distance between the balloon and the mic right – this is the best I managed. It’s not bad, but I think I can do better. Time to buy more balloons!
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Audio flash trigger…
I’ve spent the last couple of days building an audio flash trigger. The idea is that it fires the flash when it hears a loud noise, like a balloon popping or an egg smashing. So far, I’ve spent under £2 on the project. When I’m happy with it I’ll post some more info, build pictures and instructions etc.
It works, but it ’s going to need a little bit of practice to get any decent results. This is the best I’ve managed so far:
The next stages are to:
- Solder up what I’ve got, so I can use my plugboard for something else
- Build a delay box to give better control over when the flash fires
- Either buy a new flash with power controls, or modify my existing flash (Replace the LDR with a variable resistor) – a lower output from the flash should be a shorter burst of light, which will reduce the motion blur I’m getting
- Sort out a black background cloth, and arrange some more interesting lighting!
- Get myself a lense that’s better suited to this than the one I’ve got…
Posted in Cameras, Experiments, Photos | Comments Off
I’ve got a new camera!
Yay for new toys! I’ve finally given in and bought a digital SLR. Mainly because I got fed up with scanning 35mm film. Medium format I can cope with, 35mm is too fiddly and I just haven’t got the knack for laying it flat.
So, I’ve got a Nikon D80…
Off camera flash, ghetto studio setup can be seen in the setup shot…
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Photos that shouldn’t work…
I’m so surprised that this photo actually worked, that even though it’s technically uninteresting I’m putting it up as todays photo anyway. I may try to take a few more using this technique…
Click the photo for details of how it was taken.
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New toys, old toys
My new toys were delivered the other day. I’ve bought myself some wireless flash triggers so I can fiddle with off camera flash.
Unfortunately, my experiments are a little hit and miss as I don’t have the luxury of a digital SLR to learn my technique with. So I figure that if things are going to go wrong, I may as well encourage them and use the holga rather than anything consistent…
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Holga plus 35mm
I’ve been experimenting with my Holga, putting 35mm film in to see if it’s worth bothering. Judging by the results, I don’t think it is. Out of the roll I shot, I think this is the best shot…
…and I’m not particularly happy with it.
The 35mm film is much narrower than the 6×6 mask I normally have in my holga, and this means that it’s harder to gauge how the image is going to be framed. This gets tricky if you’re used to shooting full frame with the Holga, and explains why the postbox is squashed up against the right of the frame.
Other problems include not knowing how much film you’ve got left (as you lose the frame counter if you’re using 35mm) and having to unload in the darkroom.
All in all, I think I’ll stick to 120 rollfilm!
Posted in Experiments, Photos | 1 Comment »
