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by Alan Johnstone
Sun Mar 13, 2016 7:01 pm
Forum: Troubleshooting
Topic: Raspbery pi 3 Wifi
Replies: 3
Views: 846

Re: Raspbery pi 3 Wifi

Well much to my surprise that worked. I can now use the Pi with the case on and I am connecting to a router about 15m away in another room.

Alan
by Alan Johnstone
Sun Mar 13, 2016 4:49 pm
Forum: Troubleshooting
Topic: Raspbery pi 3 Wifi
Replies: 3
Views: 846

Re: Raspbery pi 3 Wifi

Update I have been using one of those transparent plastic cases designed for the Rpi 2. Taking the top off that allows the wifi to work at least as far away as the other side of the room. I do not have an "official" rpi case to test but i do not see how it can be any diferent unless it is made of s...
by Alan Johnstone
Sat Mar 12, 2016 8:54 pm
Forum: Troubleshooting
Topic: Raspbery pi 3 Wifi
Replies: 3
Views: 846

Raspbery pi 3 Wifi

I have just got my Rpi3 and set it up to work headless with no problems. I happened to have the pi plugged in within a meter of the router. I have now tried to move it a few yards away and I cannot see it on the network. Moving it back to the original spot and it reappears. So I assume that the inbu...
by Alan Johnstone
Tue Dec 17, 2013 3:44 pm
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 173201

Re: Pure Python camera interface

If I understand what you are doing correctly you are producing an average of a number of pictures then looking at the difference of that average compared to a new image. You then look for differences. If there was no movement you expect a black screen but what you get shows the sky as lighter. You t...
by Alan Johnstone
Tue Dec 17, 2013 8:36 am
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 173201

Re: Pure Python camera interface

What exactly is "fixed pattern noise"? I thought the definition of noise was that it was random.

Alan
by Alan Johnstone
Wed Dec 11, 2013 8:26 pm
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 173201

Re: Pure Python camera interface

Help, I have just upgraded to .8 and nothing works. I get : Traceback (most recent call last): File "/testshow.py", line 39, in <module> with picamera.PiCamera() as camera: File "/root/.local/lib/python2.7/site-packages/picamera/camera.py", line 238, in __init__ self._init_camera() File "/root/.loc...
by Alan Johnstone
Tue Dec 10, 2013 11:32 am
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 173201

Re: Pure Python camera interface

Help, I have just upgraded to .8 and nothing works. I get : Traceback (most recent call last): File "/testshow.py", line 39, in <module> with picamera.PiCamera() as camera: File "/root/.local/lib/python2.7/site-packages/picamera/camera.py", line 238, in __init__ self._init_camera() File "/root/.loca...
by Alan Johnstone
Sun Nov 10, 2013 5:42 pm
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 173201

Re: Pure Python camera interface

img[:,:,:-1] worked and I am sure is much faster than my method. I new that numpy stored images heightxwidthxBGR but the SimpleCV image command img=Image(cvsimage=True) is supposed to sort that. It doesnt. I tried eliminating the ByteIO object and the Decode method by simply importing an image into ...
by Alan Johnstone
Sat Nov 09, 2013 4:49 pm
Forum: Camera board
Topic: Opencv running headless RPI
Replies: 0
Views: 1074

Opencv running headless RPI

I am running my Raspberry headless using TightVNC Viewer. I have just got the pi camera and was wanting to use it with Opencv in Python. However I do not seem to beable to display the images using cv2.imshow("window Name",Image) Is there a way round this? I know everything else is working because I ...
by Alan Johnstone
Sat Nov 09, 2013 4:19 pm
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 173201

Re: Pure Python camera interface

CORRECTION in the above code change:
image = cv2.imdecode(data, 0)

to
image = cv2.imdecode(data, 1)
by Alan Johnstone
Sat Nov 09, 2013 4:16 pm
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 173201

Re: Pure Python camera interface

This works though I am sure there are numpy experts who can do better import io import time import picamera import cv2 import numpy as np # Create the in-memory stream stream = io.BytesIO() with picamera.PiCamera() as camera: camera.start_preview() time.sleep(2) camera.capture(stream, format='jpeg')...
by Alan Johnstone
Sat Nov 09, 2013 12:35 pm
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 173201

Re: Pure Python camera interface

I think I was a little hasty saying the new version of getting an Opencv image worked.When I tried it first the camea was pointing at the ceiling and I did not look closely at the result. First I think you are asking for a grayscale image by using cv2.imdecode(data, 0). I think the 0 must be a 1. Th...
by Alan Johnstone
Thu Nov 07, 2013 6:02 pm
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 173201

Re: Pure Python camera interface

Thanks, that works which is a great start as I have not found any other solution that allows me to use the Python IDE with the Rpi Camera.
I am not sure how much extra time the conversion is going to take.
by Alan Johnstone
Thu Nov 07, 2013 12:27 pm
Forum: Camera board
Topic: Pure Python camera interface
Replies: 462
Views: 173201

Re: Pure Python camera interface

I am using your example code to try to get an openCV image
I get the following error:

TypeError: expected string or Unicode object, _io.BytesIO found.

What am I doing wrong?

Thanks
by Alan Johnstone
Thu Nov 07, 2013 9:40 am
Forum: Beginners
Topic: Simplecv + Camera board guide
Replies: 24
Views: 39849

Re: Simplecv + Camera board guide

Is there a way to use this running python in the IDE ?
by Alan Johnstone
Thu Nov 07, 2013 9:27 am
Forum: Python
Topic: ipython notebook unstable? (ipython kernel keeps crashing)
Replies: 4
Views: 4185

Re: ipython notebook unstable? (ipython kernel keeps crashin

You guys are getting further than me.
I get the IPython dashboard up but nothing happens when I press New Notebook.

Any ideas
by Alan Johnstone
Sat Oct 19, 2013 10:55 am
Forum: Automation, sensing and robotics
Topic: Calculating position using Triangulation
Replies: 0
Views: 1145

Calculating position using Triangulation

Last Christmas I was given a Raspberry Pi for Christmas and dived into building a robot to roam around my large garden. I found : - the GPS was highly inaccurate due to the large trees blocking the view of the sky - the Accelerometer compensated compass worked well away from the robot but I never ma...
by Alan Johnstone
Sat Apr 13, 2013 7:43 pm
Forum: Python
Topic: spidev xfer2 v xfer
Replies: 5
Views: 17257

Re: spidev xfer2 v xfer

I found this on a google site " Some new update after a day, the code r = spi.xfer2([1,(8+adcnum)<<4,0]) could be altered like this r = spi.xfer2( ,speed_hz,delay_usecs,bits_per_word) if you put 0 for delay_usecs nothing happens it still 220us delay if i put 1000 in delay_usecs the delay is 1220us. ...
by Alan Johnstone
Wed Apr 10, 2013 10:48 am
Forum: HATs and other add-ons
Topic: USB drive
Replies: 4
Views: 1642

Re: USB drive

That worked as far as the eject command now "works" in that the drive dissappears from File Manager. However I get the same behaviour when I replug the stick. The old file system image is there but the new added file is not. Ther Mount Volume is greyed out so I cannot use that. Am I missing the "mou...
by Alan Johnstone
Wed Apr 10, 2013 9:09 am
Forum: HATs and other add-ons
Topic: USB drive
Replies: 4
Views: 1642

Re: USB drive

No, I am not. It seems to mount by itself the first time I plug the USB stick in. ie the RPi is running without the USB stck attached and I hot plug the stick in then I get a message on the desktop saying removeable media is inserted I can read it OK. In File Manager right clicking the drive gives M...
by Alan Johnstone
Mon Apr 08, 2013 8:26 pm
Forum: HATs and other add-ons
Topic: USB drive
Replies: 4
Views: 1642

USB drive

I have a USB drive working that has revolutionised how I can transfer files between my Pi and the outside world - in both directions. One fly in the ointment is that although I can hot plug/unplug it (ie the new drive is detected) the image of what is on the drive is not updated. What I mean by that...
by Alan Johnstone
Thu Apr 04, 2013 8:38 am
Forum: Python
Topic: spidev xfer2 v xfer
Replies: 5
Views: 17257

Re: spidev xfer2 v xfer

Looking in more detail at the output in the Arduino I am forced to the conclusion that: 1 xfer and xfer2 do exactly the same thing with a list of data. 2 They both bring the SS line LOW and send ALL the data in the list and then bring the SS line up HIGH 3 THEN they both repeat the SS LOW/SS HIGH se...
by Alan Johnstone
Wed Apr 03, 2013 7:01 pm
Forum: Python
Topic: spidev xfer2 v xfer
Replies: 5
Views: 17257

spidev xfer2 v xfer

I am using spidev to transfer data between my Rpi and Arduino with the RPi as Master. I understand from using help(spidev) that xfer transfers the list of data given raising and lowering the ss line inbetween each byte while xfer2 lowers the ss line at the begining of the data transmission and raise...
by Alan Johnstone
Mon Feb 18, 2013 5:46 pm
Forum: Troubleshooting
Topic: Wifi stops working when out of range
Replies: 1
Views: 475

Wifi stops working when out of range

I run my Rpi using SSH or VNC. Recently I have added agps module which is working well and I have started taking the RPi for#a walk to see how accurate the GPS is. (answer: quite accurate but not accurate enough to guarantee the robot it is intended to pilot will not go for a swim in the garden pond...
by Alan Johnstone
Fri Feb 08, 2013 2:54 pm
Forum: Python
Topic: Finding Info on libraries
Replies: 3
Views: 906

Re: Finding Info on libraries

Thanks for that. I can now see why I could not see fix as member of data. It is sad that such a wonderful module is not better documented. Just in case anybody is interested the code below ( basterdized from something I found on the internet) accesses the GPS data that is read in a thread as it must...

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