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by sjm
Tue Oct 30, 2018 9:25 am
Forum: Automation, sensing and robotics
Topic: Creating a Self driving Lawnmower
Replies: 6
Views: 3498

Re: Creating a Self driving Lawnmower

There isa nother thread on this subject: https://www.raspberrypi.org/forums/viewtopic.php?f=37&t=172960&p=1107117#p1107117 As I said in that thread I had a go at building a self navigating robot lawnmower. My lawn is surrounded mainly by patio so rather than any clever navigation I used a camera poi...
by sjm
Sun Mar 26, 2017 3:11 pm
Forum: Python
Topic: Give pygame window focus programatically
Replies: 2
Views: 1211

Re: Give pygame window focus programatically

Dave - I don't care what the others say about you - you're a genius. Worked a treat - many thanks.
by sjm
Sat Mar 25, 2017 8:27 pm
Forum: Python
Topic: Give pygame window focus programatically
Replies: 2
Views: 1211

Give pygame window focus programatically

Is there any way to give a pygame window focus programatically? I have a program that uses pygame to display some images. If I hit enter my program opens another (opencv) window. Once I have finished with that window (and hit escape) I want the program to focus back on the pygame window. Is this pos...
by sjm
Thu Mar 16, 2017 9:58 am
Forum: Python
Topic: Computer Vision Libraries?
Replies: 3
Views: 982

Re: Computer Vision Libraries?

Similar query here which may be relevant.

viewtopic.php?f=37&t=173325&p=1108508#p1108508
by sjm
Fri Mar 03, 2017 9:12 am
Forum: Troubleshooting
Topic: Mystery... Program and browsing history disappeared!?
Replies: 3
Views: 901

Re: Mystery... Program and browsing history disappeared!?

I have tried as you suggested and saved files disappear on rebooting. I will try a new SD card.
by sjm
Thu Mar 02, 2017 10:15 am
Forum: Troubleshooting
Topic: Mystery... Program and browsing history disappeared!?
Replies: 3
Views: 901

Mystery... Program and browsing history disappeared!?

Last night my daughter and I spent 30 minutes or so editing and running a Python program using IDLE after which we shutdown the pi using the shutdown button in the desktop. During the 30 minutes I'd also done several google searches. This morning when I turned the Pi back on there was no trace of th...
by sjm
Mon Feb 06, 2017 3:07 pm
Forum: Troubleshooting
Topic: Accessing Pi2 files on a Pi3/Zero
Replies: 13
Views: 1981

Re: Accessing Pi2 files on a Pi3/Zero

Finally got around to buying a new SD card reader (for 1 quid from a pound shop...) and it worked fine. I have now recovered all my files - thanks!
by sjm
Fri Feb 03, 2017 9:51 am
Forum: Automation, sensing and robotics
Topic: Head Tracking with Pi Camera
Replies: 2
Views: 2394

Re: Head Tracking with Pi Camera

You can do face detection (not sure about rotation...) in images using opencv. There are quite a few articles on the web about how in install opencv that are very complicated but the method described in this article (not about face detection) is MUCH simpler and worked for me: http://trevorappleton....
by sjm
Tue Jan 31, 2017 11:54 am
Forum: Automation, sensing and robotics
Topic: Automated mower for a large yard
Replies: 21
Views: 20143

Re: Automated mower for a large yard

I have a similar project on the go at the moment although on a smaller scale. I built my own chassis using aluminium angle - just cut it to size and bolt it together and I ended up building my own motor controller in the end. I use two 12V High-Power (HP) 25D mm Gearmotors attached to 2 Dagu Wild Th...
by sjm
Mon Jan 23, 2017 10:40 am
Forum: Troubleshooting
Topic: Accessing Pi2 files on a Pi3/Zero
Replies: 13
Views: 1981

Re: Accessing Pi2 files on a Pi3/Zero

OK - It is a very old card reader so maybe that is the issue. Just for my education how did you conclude that from the output of dmesg?
by sjm
Mon Jan 23, 2017 7:13 am
Forum: Troubleshooting
Topic: Accessing Pi2 files on a Pi3/Zero
Replies: 13
Views: 1981

Re: Accessing Pi2 files on a Pi3/Zero

I get this: [33965.260232] usb 1-1.4: USB disconnect, device number 7 [33973.009796] usb 1-1.4: new high-speed USB device number 8 using dwc_otg [33973.111993] usb 1-1.4: New USB device found, idVendor=0dda, idProduct=2026 [33973.112013] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNum...
by sjm
Sun Jan 22, 2017 10:31 pm
Forum: Troubleshooting
Topic: Accessing Pi2 files on a Pi3/Zero
Replies: 13
Views: 1981

Re: Accessing Pi2 files on a Pi3/Zero

I don't know what I'm looking for to be honest but amongst the multiple lines returned are things like: scsi 1:0:0:0: Direct-Access ICSI IC1210 CF 1.4F PQ: 0 ANSI: 0 CCS sd 1:0:0:0: Attached scsi generic sg0 type 0 scsi 1:0:0:1: Direct-Access ICSI IC1210 MS 1.4F PQ: 0 ANSI: 0 CCS sd 1:0:0:0: Attache...
by sjm
Sun Jan 22, 2017 9:51 pm
Forum: Troubleshooting
Topic: Accessing Pi2 files on a Pi3/Zero
Replies: 13
Views: 1981

Re: Accessing Pi2 files on a Pi3/Zero

thanks for the suggestion. I have tried it on both the sd card I am trying to recover files from and the sd card that I know is OK and for both I get the same result: mount: special device /dev/sda1 does not exist mount: special device /dev/sda2 does not exist mount: special device /dev/sda5 does no...
by sjm
Sun Jan 22, 2017 1:37 pm
Forum: Troubleshooting
Topic: Accessing Pi2 files on a Pi3/Zero
Replies: 13
Views: 1981

Re: Accessing Pi2 files on a Pi3/Zero

Hi, I've only just got around to trying this but it didn't work. The raspberry pi sd card isn't recognised when I connect it to the USB sd card reader. I have tried with both the sd card I am trying to recover files from as well as another rasbian sd card that I know is OK and the result is the same...
by sjm
Tue Jan 10, 2017 7:51 am
Forum: Troubleshooting
Topic: Accessing Pi2 files on a Pi3/Zero
Replies: 13
Views: 1981

Accessing Pi2 files on a Pi3/Zero

Hi, I have a Pi2, a Pi3 and a zero. I have managed to break the Pi2 and although I had backed up most of the files there were some files that I hadn't. The SD card won't work on the Pi3 or zero as it was an earlier version of Raspbian. Is there any way I can access the files on the Pi2 SD card? I do...
by sjm
Tue Dec 13, 2016 9:08 am
Forum: Automation, sensing and robotics
Topic: Human following robot
Replies: 4
Views: 4240

Re: Human following robot

Great. Good luck with the project.
by sjm
Wed Dec 07, 2016 10:41 am
Forum: Automation, sensing and robotics
Topic: Human following robot
Replies: 4
Views: 4240

Re: Human following robot

Another option may be to use a camera attached to the pi and then use image processing to identify the human (or something worn by the human) and get the robot to move towards it. There was an article in an old mag pi that did something similar. See below: https://www.raspberrypi.org/magpi/issues/28/
by sjm
Fri Nov 18, 2016 8:26 am
Forum: Automation, sensing and robotics
Topic: Impact sensing project
Replies: 5
Views: 2761

Re: Impact sensing project

I've done something very similar and used an accelerometer to detect a sudden change in force. The article that gave me the idea was on page 35 of MagPi magazine issue 40. https://www.raspberrypi.org/magpi-issues/MagPi40.pdf Here's an article to help with set up of the sensor. http://www.stuffaboutc...
by sjm
Mon Nov 14, 2016 1:25 pm
Forum: Automation, sensing and robotics
Topic: Suitable driver for "High power" 12v DC motors
Replies: 4
Views: 1381

Re: Suitable driver for "High power" 12v DC motors

Thanks - I was planning to do via a transistor and use a protection diode as described on the excellent electronics club website (perfect for beginners like myself) http://electronicsclub.info/transistorc ... #switching
by sjm
Fri Nov 11, 2016 3:39 pm
Forum: Automation, sensing and robotics
Topic: Suitable driver for "High power" 12v DC motors
Replies: 4
Views: 1381

Re: Suitable driver for "High power" 12v DC motors

Great thanks for the quick reply. All looks a bit pricey - I'll investigate the relay route I think...
by sjm
Fri Nov 11, 2016 1:59 pm
Forum: Automation, sensing and robotics
Topic: Suitable driver for "High power" 12v DC motors
Replies: 4
Views: 1381

Suitable driver for "High power" 12v DC motors

Hi, Let me start by saying I am very much a beginner when it comes to electronics. I'm building a robot am using the following motors: http://www.technobotsonline.com/pololu-99-1-100rpm-25d-high-power-12v-geared-motor.html According to the specs they have a "stall current" of 5.6A. Following some Go...
by sjm
Tue Jul 26, 2016 6:23 pm
Forum: Graphics, sound and multimedia
Topic: omxplayer plays videos too fast
Replies: 8
Views: 6924

Re: omxplayer plays videos too fast

I have managed to find a solution thanks to this:
http://www.raspberrypi-spy.co.uk/2013/0 ... ra-module/

and using MP4Box instead of avconv
by sjm
Sun Jul 24, 2016 8:41 am
Forum: Graphics, sound and multimedia
Topic: omxplayer plays videos too fast
Replies: 8
Views: 6924

Re: omxplayer plays videos too fast

I recorded the videos from python using standard picamera recipe: import picamera from datetime import datetime with picamera.PiCamera() as camera: # From picamera documentation Recipe 4.10 camera.resolution = (640, 480) collisionTime=datetime.now().strftime('%a_%d_%b_%Y_at_%H:%M:%S') camera.start_r...
by sjm
Sat Jul 23, 2016 9:34 am
Forum: Graphics, sound and multimedia
Topic: omxplayer plays videos too fast
Replies: 8
Views: 6924

Re: omxplayer plays videos too fast

Hi,

Thanks for your quick reply. I have tried both options you suggest (converting the file using avconv and using the --fps option on omxplayer). Unfortunately neither have any affect. The video still plays at the same very quick speed...

Has anyone any other ideas?

Regards,
Jonathan
by sjm
Sat Jul 23, 2016 7:24 am
Forum: Graphics, sound and multimedia
Topic: omxplayer plays videos too fast
Replies: 8
Views: 6924

omxplayer plays videos too fast

Hi, I have recorded a 10 second .h264 video file on my pi. When I attempt to play it back on the Pi using omxplayer it plays the whole video in about a second or two. If I copy the file and play it on a Windows PC using VLC media player it plays completely normally - i.e. in about 10 seconds. Any id...

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