I am working on augmented reality with GPS & Camera interface but more often I am having this calibration message as 'Compass Interference' see image.
a busy cat http://static.iphonelife.com/sites/iphonelife.com/files/imagecache/teaser_thumb/u2440/compass8.jpg
this is appearing very often, while in other apps it working fine with very less such messages.
Is there any thing needs to be changed or is it normal.
Related
I was able to make a working HID USB stack on my "StartUSB for PIC" board for the 18F2550 microcontroller. I based it on one of the MLA libraries, which was made for the 18F45K50 (MLA 2018_11_26, hid_custom, picdem_fs_usb_k50.x), but I converted it to work with the 18F2550 (there might have been easier ways, but only learned to work with PIC about 1 month ago). On the host side, I'm using LibUsbDotNet (also here, there might be easier ways - the documentation on this library really sucks) on a Windows 10 machine.
I'm using the HID class, full speed, and all seems to work. Although, I get some random errors on the host PC (see below), but doing one close/re-open cycle on the host side when getting the error is kind of solving it. Dirty, but it works. So I kind of ignore this now.
Win32Error:Win32Error:GetOverlappedResult Ep 0x01
995:The I/O operation has been aborted because of either a thread exit or an application request.
I'm not an expert on USB (yet). But all examples I'm seeing are based on 1) you send first a command to the device and 2) then you retrieve the answer from the device. I did some performance tests, and see that this indeed shows that I can do about 500 cycles/second. I think that is correct, because each cycle, sending command and retrieving answer, each takes 1 msec.
But do I really need to send a command? Can't I just keep reading endlessly, and when the device has somthing to say, it does send the data in an IN transaction, and when not it ignores which creates a timeout on the host side. That would mean that I can poll at 1000 cycles/second? Unfortunately, I have tried it by changing my implementation on the PIC, but I get very weird results. I think I have issues with suspend mode. That brings me to another question - how can I make the device get out of suspend mode (means that not the host, but the device should be triggering this event). I have searched the MLA library for command such as "wakeup", "resume", ... but couldn't find anything.
So, to summarize, 2 questions:
Conceptual: Can I send data from device to host without being requested for it by a command from the host?
For PIC experts: How can I have a device trigger for a wakeup from suspend mode?
And indeed, the answer is Yes on the first question.
In the meantime, I found another link on the web that contains a Visual Studio C# implementation of a USB library including all the source files.
If you're interested, this is the link
This C# host implementation works as a charm. Without sending a command to the device, I get notified immediately if a button is pressed. Great!
It also proofs that my earlier device implementation based on the original MicroChip MLA, is 100% correct. I stress tested the implementation by sending a "toggle LED command" as fast as I could, and I reach 1000 commands/second. Again great!
I think that LibUsbDotNet isn't that perfect after all. As I wrote above, I get rather unstable communication (Win32Error). But with this implementation, I don't get a single error, even after running for half an hour # 1000 commands/second.
So for me, case closed.
Am using this commit of uvc-gadget together with g_webcam as of 4.4.143 for Rockchip. This version of uvc-gadget only transmits a static mjpeg image (and is much better written than earlier sources of uvc-gadget).
Observing interesting behavior on host laptop, which is receiving the stream from gadget with guvcview: after a while frames start to flicker like an old TV (V4L2_CORE: (jpeg decoder) error while decoding frame), and then eventually the stream breaks down on host: V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable. Underneath host continues polling ([75290.124695] uvcvideo: uvc_v4l2_poll), there is no error neither in host's dmesg, nor in uvc-gadget on device. In fact, after re-opening guvcview streaming works again without uvc-gadget restart, but soon crashes in the same way.
I'm using stock USB3.0 cable, which is both for streaming and powering the device. AFAIK, there is no source of noise that may result in such kind of strange flickering on physical level.
Additionally, I've noticed with smaller USB packet sizes going down from 1024 to 256, stream survives for longer (up to 50,000 frames or so), but still finally crashes.
Any idea what's going on here?
UPDATE
After I switched from MJPEG-compressed to uncompressed stream, there is no longer flickering, but still always loss of contact after several seconds: V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable
I have a vb.net application that is able to read gps info from gps connected to usb. This works on about 50-60 different computers and gps devices, however there is one gps device (did try it on several computers aswell) that this will not work on.
I did think there might be something wrong with the gps device, but there are two other applications (Haicom Viewer and a custom application I do not have the source code for) that works with that device without any issues. So there has to be something with my application that is not able to work with that specific device.
Currently I'm using a SerialPort control and when using Read() I get "blank" bytes and ReadLine() times out.
I have tried different BaudRates, Encodings and Hanshakes.
I managed to make it work by setting DtrEnable = True on the SerialPort control. However I do not know why that was the deciding factor. If anyone could explain why only 1 of many GPS devices needed this to be true it would be much appreciated.
I used successfully my raspberry camera times ago.
Now I tried again to acquire a image with the raspistill -o image.jpg command; the red led on the camera flashes, but I get this error:
mmal: No data received from sensor.
Check all connections, including the Sunny one on the camera board
Of course the camera connections are fine. Is there any other way to check if the camera is still working?
This error usually appears because of a faulty connection with the camera.
I had the exact same problem in different camera+Pi configurations. The following case is what I encountered:
The connector is not correctly inserted either in the camera or in the Pi.
The Sunny connector (the small yellow one on the camera) is not connected well.
(now it gets interesting)
If you often remove and reinsert the camera in the Pi please be sure to remove all power from the Pi. The sensor is very sensitive and a spark on the wrong pin could burn it. (I did this already unfortunately)
This could also trigger a problem with the Pi connector pins. It was somewhat confirmed that for Pi2 the connector may have some bad soldering which could lead to cold contact soldering. You can fix this by using some flux on the pins and then pass the soldering iron hot end over the pins to remake the connection.
I used a longer cable that had both connectors on the same side of the cable. If you connect it like it is you can burn your sensor and the Pi will not start because of the power surge (also the camera gets very hot in this case). DO NOT REMOVE IT from the Pi without removing power before. To a cable like this you have to remove the blue plastic from one end and bend the connector with the contacts on the other side. Insert this end in the camera since this will not be removed/inserted as often as the Pi end.
Make sure that the silver contacts are well inserted into the PCB connector.
(video here)
Also, make sure that the sunny connector is firmly attached.
This fixed it for me.
I was experiencing the same problem too, until I found a solution.
I removed the sunny connector(the yellow thingy below the camera in the board) and fixed it in the same place. The camera is working fine after trying this.
I have got the same issue. I have find out it was a power supply issue.
Try to change your cable and/or your raspberry power supply adaptor.
You check if this is your reason of your problem by typing:
$ dmesg
if you see something like this:
[ 44.152029] Under-voltage detected! (0x00050005)
-> Then replace your power supply! :D
The only fix for me was to purchase a new camera.
No real root causes identified.
My problem was I put the camera in, while the Pi was on. which might
have made the camera shot. i.e the camera module is static sensitive
and it's possible that it's been damaged
Unfortunately if this is the case there's nothing you can realistically do to fix it, just get a replacement.
This specific error shows when another application is using the camera. In my case, it was motion.
It might be possible that the cable is placed the wrong way. I had this problem and after multiple tries I realized that was the problem.
I built a navigator and have a problem with the GPS, sometimes it takes forever to get a GPS-fix even though the device is outside with nothing blocking it. If I start TomTom the GPS gets a fix almost instantly on the same device. I can also get a fix faster if I restart the device.
Its like the GPS is in a sleep mode and has to be "poked" for it to start sending coordinates. Anyone knows anything about this and how to get it working faster in win CF c#?