Having trouble tying to find a solution for such a seemingly simple operation in SparkAR.
I basically want a pulse to happen, then wait xx seconds and pulse again and keep repeating.
I have looked everywhere and can't seem to find any solution. My first time posting here, so hoping someone might be able to shed some light!
Also, is there any way to "force" a filter to restart (as if just opened) after a given period?
Regards,
Andy
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I have a problem with calculating OR confidence intervals from a glm in the latest version of R, but I have not had this issue before. With any glm where family="binomial", no matter how simple the model is, it will easily allow me to extract the summary and exp(coef(model)), however when I try to extract the confint() or exp(confint(model)), the "Waiting for profiling to be done..." message is displayed and nothing happens (I've waited up to 10 mins then cancelled the procedure, this usually takes only seconds on my machine). Any ideas what might be tripping this function up? I've tried it on multiple datasets and variables, with the same result. Any ideas why it is taking so long/failing to finish?
Well, for some unknown reason, specifying exp(confint.default(model)) leads to instant resolution of this problem.
I am attempting to stream audio files from a server to iOS devices and play them completely synchronized. For example on my phone I might be 20 secs into a song and then my friend next to me should also be 20 secs into the song as well. I know this is not an easy problem to solve, but I am attempting to do so.
I can currently get them within one second of each other by calculating the difference in time between the devices and then have them sync up, however that is not good enough because the human ear can detect a major difference in a second and this is over WIFI.
My next approach is going to be to unicast the one file from the server and then have the all devices pick it up directly from the server and then implement some type of buffer system similar to netflix so that network connectivity would be a limiting factor. http://www.wowza.com/ is what I would use to help with that.
I know this can be done, because http://lysn.in/ is does it with their app and I want to be able to do something similar.
Any other recommendations after I try my unicast option?
Would implementing firebase help solve a lot of the heavy lifting problems?
(1) In answer to ONE of your questions (the final one):
Firebase is not "realtime" in "that sense" -- PubNub is probably (almost certainly) the fastest "realtime" messaging for and between apps/browser/etc.
But they don't mean real-time in the sense of real-time, say, as race game engineers mean it or indeed in your use-case.
So firebase is not relevant to you here and won't help.
(2) Regarding your second general question: "how to synchronise time on two or more devices, given that we have communications delays."
Now, this is a really well-travelled problem in computer science.
It would be pointless outlining it here, because it is fully explained here http://www.ntp.org/ntpfaq/NTP-s-algo.htm if you click on "How is time synchronised"?
So in fact, to get a good time base on both machines, you should use that! Have both machines really accurately set a time to NTP using the existing (perfected for decades) NTP synchronisation.
(So for example https://stackoverflow.com/a/6744978/294884 )
In fact are you doing this?
It's possible that doing that will solve all your problems; then just agree to start at a certain exact time.
Hope it helps!
I would recommend against using the data movement to synchronize the playback. This should be straightforward to do with a buffer and a periodic "sync" signal that is sent at a period of < 1/2 the buffer size. Worst case this should generate a small blip on devices that get ahead or behind relative to the sync signal.
does anyone know if it would be possible to call the CMStepUpdateHandler block without waiting for the quoted number of steps?
The reason I want this, is that if the user starts the startStepCountingUpdatesToQueue:updateOn:withHandler: and suspends the app, only to reopen AFTER they have finished walking, the step count will not update as it is necessary to then walk the quoted number of steps with the app in the foreground before the steps are displayed.
Any help greatly appreciated.
PS, see here for documentation... https://developer.apple.com/LIBRARY/IOS/documentation/CoreMotion/Reference/CMStepCounter_class/Reference/Reference.html
Having researched this, it seems the behaviour above is default, and so opted to use the CMStepCounter query option.
I have a PIC32MX340F512 board developed by another company for us, The board has a DS1338 RTCC and 24LC32A eeprom, and display unit on an I2C bus, on this bus i included a TSL2561 I2C light sensor, i wrote code in c to poll the light sensor continously , when the light sensor reaches a certain level i save the time and date and light sensor value on SD card. This all works fine but if i leave the system without exposure to light inside tunnel where incident light on one end of the tunnel is ought to be monitored the system becomes unresponsive no matter how much amount of light you apply and then if i switch power off and back on again everything starts to work normal. i am a one man development team and have been trying to find out the problem for months, i activated the watchdog timer to prevent the system from hanging but the problem still persisted. i then decided to find out if the problem is with the sensor by including a push button to activate light measurement but still when 4-5 hours elapse the PIC cant even detect a change in the the input pin. Under the impression that a hardware reset overrides anything going on i included a reset button and it also works ok for the first few hours after that the PIC doesn't seem to be responding to anything including a reset. I was getting convinced that there is nothing wrong with the firmware but also with all this happening the display unit (pic16f1933 and lcd) on the I2C shares power with the main unit and doesn't seem to be affected as it alternates between different messages constantly Does anybody have an idea what could be wrong (hardware/firmware or my sensor). I am using a 24v DC power supply purchased seperately. The PIC seems to go into a deep sleep although i dd not implement any kind of SLEEP mode in my code. Nb We use the same board for many other projects and i haven't come across such a problem . Thanks in advance.
I think you need to (if you haven't already) explore the wonderful world of in-circuit-debugging (such as with the ICD3 or PICkit 2/3). It allows you to run the processor in a special mode that lets you pause execution, see exactly which line of code is being executed, inspect variable values, and step through the code to see which parts are running and not running, or see exactly where execution takes a wrong turn. If the problem takes hours to reproduce, that's okay. You can just leave it overnight running in debug mode and hopefully it will be locked-up or 'sleeping' in the morning. At this point, you will be able to pause the processor and poke around to see if you got caught in some kind of infinite loop or something. This is often the only way to dig inside a running piece of code to see why things aren't working as you expect. But as you say, those bugs that take hours or days to manifest are the trickiest. Good luck!
It sounds like you can break up your design into two main parts, sd card interfacing, reading the rtc and reading the light sensor. If it were me I would upload a version of the code that mimics reading the light sensor but only returns fake data and see if that cures the problem. Additionally do the same with the other two modules separately and see if any of the three versions of your project not show this problem. From there just keep narrowing it down until you find the block of code thats causing problems.
if Two or more versions of your debug code show the same problem then my guess is it has to do with one of the communication protocols. I had a problem with a Pic32 silicon version blocking when using the DMA in conjunction with the SPI peripherals. So I would suggest checking the errata for your chip.
If you still cant find the problem, my only suggestion would be to check for memory leaks or arrays that are growing into reserved memory.
Hope that helps, good luck!
I've seen is posible to know what applications are running with getVisibleApplications()from "ApplicationManager" class but, is it possible to know how long were these applications used?
Thanks
If you really needed this information it would be possible.
You could have a background process start a timer and every N minutes it could call getVisibleApplications() and keep track of what has been added or removed to the list.
The difficulty is finding the right balance between accurate data and battery life as a very small value of N (seconds/minutes) will prevent the device from sleeping and will cause severe battery life degradation. A very large value of N will have minimal effect on battery life but the data won't be very accurate.
You could also combine it with events... maybe you would monitor aggressively when the backlight was on and hourly when it's off.
Not really sure what you're trying to do so my apologies if this doesn't help at all.
Simple answer is, No you cannot the duration of how long the applications were used. Out of interest, why would you want to know that?