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by technoducky
Thu Sep 05, 2013 12:20 pm
Forum: HATs and other add-ons
Topic: Powering up 20 RPis at the same time
Replies: 3
Views: 1468

Re: Powering up 20 RPis at the same time

I would definitely go for Trevor's solution, it will likely be even cheaper than buying the additional hub, especially with bulk buy sites where you can get cheap micro USB cables for pennies.

I'm just curious though, what project will this be used in?

Dan
by technoducky
Thu Sep 05, 2013 10:21 am
Forum: General programming discussion
Topic: How to improve data transmission rate?
Replies: 3
Views: 1184

Re: How to improve data transmission rate?

Should I assume you are using the Pi's UART? Other than what you have mentioned (compression) and using a high baud rate I can't really think of a way to increase the throughput much more. I may be wrong, but overclocking technically does not make data transfer faster, just makes the Arduino process...
by technoducky
Thu Sep 05, 2013 10:14 am
Forum: General programming discussion
Topic: wut is your favorite programming language?
Replies: 28
Views: 10088

Re: wut is your favorite programming language?

It very much depends on the project, I don't really have a "favourite", I just pick the most appropriate language for the task. I suppose you could say since I tend to use either C, C++, Java or Python those would be my favourites. Also I think it's wrong to group Java and JS, they both have "Java" ...
by technoducky
Mon Sep 02, 2013 12:54 pm
Forum: General discussion
Topic: Battery pack?
Replies: 2
Views: 728

Re: Battery pack?

For powering the Pi that would be pretty good, judging from it's rated capacity and my experience of powering a Pi from batteries you should get around 8-12 hours use depending on load.
That is for the Pi alone, if you add a screen that will drastically drop.
by technoducky
Mon Sep 02, 2013 12:50 pm
Forum: General discussion
Topic: NOOB - Touch Screen
Replies: 2
Views: 1407

Re: NOOB - Touch Screen

I got one of the 2.8" TFT touchscreens texy was selling, it is pretty good for a noob as everything is pretty simple to set up, and it would well with pyGame and X server.

Send him a message if you want one: http://www.raspberrypi.org/phpBB3/membe ... le&u=12676
by technoducky
Fri Aug 30, 2013 3:53 pm
Forum: General programming discussion
Topic: C or C++
Replies: 17
Views: 4538

Re: C or C++

I am very much of the mindset that no language is superior, the application is what defines how good a language is. The fact that your friend instantly states that one language is better personally is just his way of confirming to you that he probably isn't a very good programmer. Of course C++ is d...
by technoducky
Fri Aug 30, 2013 3:47 pm
Forum: General programming discussion
Topic: How to improve data transmission rate?
Replies: 3
Views: 1184

Re: How to improve data transmission rate?

Data transmission between what?
by technoducky
Fri Aug 30, 2013 3:45 pm
Forum: General programming discussion
Topic: sudo python script in crontab
Replies: 9
Views: 33109

Re: sudo python script in crontab

Make a small script that will append the current date to a text file and add that to the crontab and see if that runs. Since you need to invoke the Python script with sudo then you may want to have cron run it as root so edit the crontab with sudo crontab -e -u root , just make sure to always use ab...
by technoducky
Fri Aug 30, 2013 3:30 pm
Forum: General programming discussion
Topic: best language for my project ?
Replies: 4
Views: 2347

Re: best language for my project ?

I know what you mean about running a webserver on an Arduino, it's almost impossible for anything even slightly complex. Buy anyway, I would say since you are using a Pi probably C++ will be best (especially since you would than have the libraries for the RF network), use this to code the a webservi...
by technoducky
Thu Aug 29, 2013 2:54 pm
Forum: Python
Topic: How to echo in python
Replies: 14
Views: 6621

Re: How to echo in python

Thanks for that I already had the gpsd bit working. But don't know how to write the GPS info to a file then shut down gpsd to use the port to transmitt the data with tty. I don't quite understand what you are saying here, from what I understand you have a GPS device connected to ttyAMA0 which you a...
by technoducky
Thu Aug 29, 2013 2:48 pm
Forum: Python
Topic: not a pulse counter!
Replies: 4
Views: 1485

Re: not a pulse counter!

It depends on what you are counting and what else your program is doing, it you will be doing anything else on the same thread as you are polling the input then I would say an interrupt would be better, or have a separate thread to poll the input.
by technoducky
Thu Aug 29, 2013 2:35 pm
Forum: Python
Topic: Give me ideas! What would you want?
Replies: 4
Views: 1016

Re: Give me ideas! What would you want?

Make a terminal based application which I can leave running on a small-ish spare monitor, it will alert me to emails (Gmail), Google Calendar, Facebook, Twitter, Steam and local weather notifications. It will give alerts by writing to the terminal in a colour unique to the type of notification and w...
by technoducky
Thu Aug 15, 2013 5:32 pm
Forum: Camera board
Topic: VLC/OpenCV streaming reliability
Replies: 2
Views: 5525

Re: VLC/OpenCV streaming reliability

I am using VLC to stream video from the camera module over RTSP to (currently one but possible more) clients which decode the stream using OpenCV which then performs some image processing and displays the image. I am piping the output of stdout from raspivid to cvlc to stream the video: raspivid -o...
by technoducky
Thu Aug 08, 2013 1:10 pm
Forum: General discussion
Topic: best cooling solution
Replies: 8
Views: 34656

Re: best cooling solution

I would check to be certain it is overheating, you can check with: /opt/vc/bin/vcgencmd measure_temp It will only shutdown at 85 degC. I somewhat doubt it is overheating, these type of SoC are designed to dissipate heat naturally and run at high temperatures since they are used in smartphones where ...
by technoducky
Wed Aug 07, 2013 12:31 pm
Forum: Graphics, sound and multimedia
Topic: Dropbox style app for android and Pi
Replies: 7
Views: 1943

Re: Dropbox style app for android and Pi

Dropbox has an API, is the obvious solution not to just write a Dropbox client that will sync in the way you want it to?
by technoducky
Mon Aug 05, 2013 3:30 pm
Forum: Camera board
Topic: diy ip multifunction door access controller
Replies: 5
Views: 4372

Re: diy ip multifunction door access controller

Not very familiar with the Wiegand interface, but if the GPIOs are too slow you could always use an external buffer IC, or even a microcontroller to buffer the interface and interface with the Pi through SPI/i2c. This is definitely my favourite method, I don't really like to use the Pi GPIO if I can...
by technoducky
Mon Aug 05, 2013 2:36 pm
Forum: Camera board
Topic: VLC/OpenCV streaming reliability
Replies: 2
Views: 5525

VLC/OpenCV streaming reliability

I am using VLC to stream video from the camera module over RTSP to (currently one but possible more) clients which decode the stream using OpenCV which then performs some image processing and displays the image. I am piping the output of stdout from raspivid to cvlc to stream the video: raspivid -o ...
by technoducky
Mon Aug 05, 2013 9:49 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Interfacing RPi to Arduino
Replies: 14
Views: 7485

Re: Interfacing RPi to Arduino

The two easiest options are to use a MOSFET level converter, which is the best option if you are using the Arduino with 5v level logic (such as a Hitachi LCD). The easiest way is to run the Arduino at 3.3v, this is done by connecting a 3.3v supply (external from the Pi due to current limitations) to...
by technoducky
Mon Aug 05, 2013 8:47 am
Forum: Camera board
Topic: Help with prog. RPi Camera seems slow for object detection?
Replies: 11
Views: 10093

Re: Help with prog. RPi Camera seems slow for object detecti

I would use MMAL to read raw pixel data from the camera, it is probably the fastest way, have a look at the userland RaspiVid code and here http://thinkrpi.wordpress.com/2013/05/2 ... board-csi/, it is still slow, but probably better than a USB webcam.
by technoducky
Fri Aug 02, 2013 3:22 pm
Forum: Camera board
Topic: Using VLC to stream from the camera - Help needed
Replies: 166
Views: 177315

Re: Using VLC to stream from the camera - Help needed

Working perfectly now. Thanks again. Is there a way to stop the feed timing out? I think the only way is to increase the timeout. So put a few 9s in the timeout value (I'm using -t 9999999 at the moment) Using -t 0 will set an infinite timeout. See RaspiVid.c at userland repo: https://github.com/ra...
by technoducky
Fri Aug 02, 2013 12:21 pm
Forum: Networking and servers
Topic: Most simple way to stream from a camera
Replies: 7
Views: 2808

Re: Most simple way to stream from a camera

It is possible to use the Raspi camera with OpenCV: http://thinkrpi.wordpress.com/2013/05/2 ... board-csi/

Although don't expect much in terms of frame rate or resolution.
by technoducky
Thu Aug 01, 2013 1:49 pm
Forum: Camera board
Topic: Automatic Number Plate Recognition
Replies: 17
Views: 20512

Re: Automatic Number Plate Recognition

I also wondered about the legalities (in the UK) of uploading the data to the web to make it searchable by anyone. If enough people contributed, it could be very interesting/dangerous!!! Personally I don't think there is a problem, as all you are doing is allowing people to view information which i...
by technoducky
Thu Aug 01, 2013 9:17 am
Forum: Camera board
Topic: RGB output from video port
Replies: 3
Views: 2230

RGB output from video port

I may be missing something very obvious here, but I am trying to get RGB888 format data out of the video port of the camera. My code is based around the example here http://thinkrpi.wordpress.com/2013/05/22/opencvpi-cam-step-6-video/ (I have tided it up a little for my project and have taken out the...
by technoducky
Wed Jul 31, 2013 10:56 am
Forum: Beginners
Topic: First experience, issues and questions
Replies: 12
Views: 3008

Re: First experience, issues and questions

If you have a noisy variable input that is both above and below the target output, do you need something called a boost-buck (step up and down) regulator? I may be completely wrong here (not knowing a lot about boat power systems, just assuming it to be fairly standard 12/24v leisure battery scenar...
by technoducky
Tue Jul 30, 2013 2:45 pm
Forum: Beginners
Topic: Removing/Desoldering Components - Any Gotchas?
Replies: 11
Views: 10967

Re: Removing/Desoldering Components - Any Gotchas?

Just removing the 3.5mm and RCA connectors should be simple. I would be happy to do this and posit it to you (depending on location of course), but you may as well try it yourself, the pads are fairly large. I would recommend some fairly wide (1-1.2mm) desoldering wick and no more than a 0.8mm iron ...

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