I recently wrote a program to display data on a set of LCD TV's. The data is for the most part static with the exception of refreshing from the database every 60 seconds. I know screen burn isn't as big an issue with LCD's as Plasma TV's, however, I would like to try and minimize the risk. These screens will be running for 8 hours a day.
I programmed a small square that bounces around the screens on top of all the data. The square constantly changes colors as it goes. I did test that it hits every pixel on the screen. It completes a "cycle" every couple of minutes.
Is that sufficient to mitigate the risk of burn in? Or do I need to make something more complicated?
Discard all the effort altogether, LCDs do not sufer from that problem at all.
And that square is probalby annoying, and even if it were to do any good, it would have to stay on the screen for longer period of time.
And - I wouldn't worry, 8 hours per day is normal. If you are paranod, you can move the window / re-place the text every so.
That is not true exactly. While LCD don't suffer from what burn in actually is. They do have a similar problem, especially when used as a computer screen, or left on a tv guide. An image will stick if left on the screen long enough, usually goes away but it can be permanent.
The program you are describing sounds like it would work just fine.
Related
I have some sort of a heatmap and I can see how my users are using my website. Now I know where they are clicking, how much time it costs to complete a set of instructions, how much do they navigate between pages, etc.
So given that I have information with of this kind:
12/12/2014 12:45:00 - User pressed button 1 on page 1
12/12/2014 12:45:15 - User pressed button 2 on page 1
12/12/2014 13:00:00 (15 minutes delay) - User pressed button 3 on page 1
Now comes the hard part - how do I process this kind of information? For example how do I know that the user is lost on my website (if there is 15 minutes delay - does this means that his phone rang or my UI is bad?). And also - how can I find some patterns in large amount of data - say every third user spends 15 minutes after the second click to find what he has to click next.
What is the correct approach here? Thanks.
In order to derive useful information from raw data you need some context. You need to be clear about what expected user behaviour is and, where appropriate, what you are aiming for the user to do (eg. buy a product, register, make a comment etc.).
For example, if you have an event splash page with a big button to book a place, and you find that a lot of people click on that button very soon after they arrive, that's probably a good thing. If you have a page full of important information that you want people to read, and they click away just as quickly - that's really not a good thing.
It sounds obvious but so many people fall in to the trap of trying to evaluate user behaviour without being clear about the context - and without acknowledging that the very same number can mean very different things depending on that context.
Evaluate each page of major section of your site and outline what is there, and how you'd expect users to interact with it. How long would you expect a user to spend on that page? Where would be the logical place to go next? Is this a logical place to leave the site (I booked, I'm done), or is a user leaving the site here a failure? And so on. Then compare these expectations to the reality you see from your heat map.
Don't get too hung up on individual cases - if one person took 15 minutes on a page that should take 30 seconds, that was probably the phone ringing. If 90% of visitors take 15 minutes, then your page needs re-evaluating.
Lastly, pay as much attention to what people don't do as what they do. Everyone's eye is drawn to the bright spots on a heat map or the rows at the top of a chart with big numbers. With analytics, a lot of the most useful information is what you expected to see people doing, but they aren't. Again, to realise this information you need to have defined that expected behaviour.
I've got a little side project going on using SDL2/SDL_mixer and a couple other sound libraries. I've been trying for a while now to synchronize my audio and video but haven't been able to get it anywhere near successfully. All new to this stuff so forgive the poorman's logic and coding. At first I thought to set the delay to SDL_Delay(30) after every frame, and then a few other numbers in that range. Not quite right. Then I tried doing it by getting Ticks. Where I would get the difference between current_ticks and last_ticks and set a delay if the delta between ticks was <=30 and set the delay to 30-delta. Still not quite right (by far). Hoping someone on here with more experience might guide me in the right direction. In regards to the video, it's a visualizer of course, seems like a popular beginners project.
The basic way you synchronize audio and video is that you choose one to use as a timer source and present the other according to that timer. The easiest is generally audio, but because it's generally buffered ahead, you need some method of measuring what time in the audio stream is actually coming out of the speakers. Once you get that, it's just a matter of waiting until the audio reaches the right time for the next video frame and displaying it.
My goal is to write a program that would capture the screen in an efficient way.
Little twist, the screen will not be saved. My program will do various check on it (pixel's colors in some area.. etc).
The program will run in windows, and will need to take(and analyze) as many screenshot as possible per second, and will not be used in games. (That imply that I need the whole screen, like pressing prntscreen. It's not a problem if that fail in fullscreen game.)
All propositions are welcome, and I'd be glad to share any missing details.
Edit
As I wrote in the comment, capturing the screen for storing purpose is really common and easy to find.
I asked to be sure to not miss any method of capturing the screen without storing it at all.
The program will look the screen, take some decision then will quickly go to the next frame.
Perhaps look into SDL
A guick google returned this screenshot code for SDL: http://lists.libsdl.org/pipermail/sdl-libsdl.org/2000-August/011387.html
This is an odd one. I am making a app that is kind of a game, and I wanted to have a shooting starburst effect. I made it one evening and it all worked well, until I noticed that my browser was eating over 300 megs of ram, eating 1 meg every 5 seconds, mainly when the starburst would happen.
Here is an example stripped down to just the starburst:
http://www.sizzln.com/example.htm
First thought, I am not removing the objects or still have references somewhere. I am placing each generated star into a Canvas, but I am removing old starts every 3 seconds. I do have a lot of DoubleAnimations as well, but I even have a callback to set everything to null.
Here is the weird part, if I convert it to WPF it doesnt happen, if I run it inside of Silverlight Spy 3, it doenst happen. If I take a Heap Dump using WinDbg and SOS.dll, it reports that it should only be using between 1.8 and 3 MBs of ram.
I have the GC running every 3 seconds to cleanup, but it never has any effect. I can see in the heapdump that many objects are now deleted, and I always get back to 1.8 meg or so after a GC, but the memory shown in Task Manager just keeps going up.
I dont know what to do, I think I am carefully removing the objects unless my Heap is not being honest.
Are you running Vista or Win7? It sounds like the OS is not reclaiming memory, as it shouldn't unless it needs to.
It may also be that the Silverlight GC doesn't free its buffers, on the assumption that the memory may need to be reallocated soon.
In either case, it doesn't sound like anything to worry about, as long as the profiler says your program only uses 1.8MB after the GC runs.
I just briefly looked over your code. You have a lot of places where you hook into events (+=), but never unhook (-=). These are hard references and therefore won't ever be collected if they are ultimately connected to a root object.
OK I am going to sorta answer my own question. Silveright doesn't have the handy "BeginAnimation" method, so I found online a quick way to add an extension to do basically the same thing, it did this by creating a storyboard and starting it.
However, it just stayed there, I dont exactly know what it was being connected to either. Calling Stop() on it after it finishes fixed my memory issue.
One odd side effect is I have to be careful when I call the stop method, when creating so many storyboards it seemed to get a bit confused and it would cause some of the objects to reappear, even after they were removed from the control.
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This isn't really a programming question, more of an ideas question. Bear with me.
My sister gave me a well-used Nokia N95. I don't really need it, but I wanted it to do some programming for it. It supports a few languages, of which I can do Python.
My question is this: what to do with it? If I think about it, it has a lot to offer: i can program the GPS, motion sensor, wireless internet, sound and visual capture; it has a lot of hard disk space, it plays sound and video and so on.
The combinations seem limitless. The way I see it, it is a device that is easily always on me, has access to a huge data repository (the internet, and my personal data in it) and can be aware if I'm sitting at home, at work, or moving about somewhere. It could basically read my google calendar to check if I should be somewhere I'm not -- perhaps give me the bus schedule to get to where I should be. It could check if it's close to my home and therefore my home PC bluetooth/wifi. Maybe grab my recent work documents from my desktop computer, along with the latest Daily Show, for the bus journey to work. It could check my library account to see if any of my books are due, and remind me to take them with me in the morning. Set up an alarm clock based on what shift I have marked in my google calendar.
Basically I have a device that can analyze my movements in time (calendars with my data etc) and space (gps, carrier cell ids). By proxy, it could identify context situations -- I can store my local grocery store gps coordinates or cell mast ids and it could remind me to bring coffee.
Like I said, the possibilities seem limitless, and therefore baffling. Does anyone else have these pseudofantastical yearnings to program something like this? Or any similar ideas? How could this kind of device integrate into -- and help -- your life?
I'm hoping we could do some brainstorming.
"Gotta Leave" - A reminder that figures out the bus time, how far you are from a stop on your bus and shows a countdown till you "Could" leave (green), "Should" Leave (yellow), "Must" leave (orange), and "Gotta Run to get there" (red).
As inputs it needs what bus number you want to ride. You turn it on, it finds you, finds your closest few bus stops, estimates your walking speed at 2/mph and calculates when you need to leave where you are to get to the bus with 5 minutes waiting or less.
You should just pick any one and implement it.
It doesn't matter where you start, more that you actually do start. Don't concentrate on the destination, take a step and see what the journey holds.
Do it for a laugh to start and your expectation will be set right for both when you do find your killer app and when you don't.
"Phone home" - an interface to report home if you send a message to your phone that it is lost / stolen. Must be a silent operation from the phone holder's perspective
Options:
Self destruct mode to save your data from prying eyes
Keep calling with it's location every 10 minutes until an unlock is sent indicating the phone is found.
This is the same problem I face with the android (albeit java instead of python). The potential is paralyzing :)
I'd recommend checking out what libraries have already been written for doing cool stuff on that phone, and then building off of them- It's a system that provides inspiration, direction, and a good head start. For instance, on the android side, I'm fooling around with "zxing", a library that lets you read barcodes via the cellphone's camera. That's it's own sub-universe of possibilities, but at least it gives me a direction to go. "do cool things with information about products physically nearby"
"Late for Work" - Determines if you are not at work, buzzes you with a reminder and preps the phone to call into the sick line. Could be used if you are going to be late as well.
Inputs: Your sick line number. Time you should be at work. Where your home is, where your work is
Optional:
Send a text message
Post to an online in/out board
If you are still at home, sound an alarm
If you are still at home, call in sick, if you are not at home sent a "I'm going to be late" message
Comedy Option:
- If you don't respond to ten alarms, dial 911
To add on to what others have said, come up with some kind of office-GPS (via WiFi maybe? Does it have WiFi?) and tell you when you need to go to a meeting.