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by riklaunim
Wed Jun 18, 2014 6:06 am
Forum: Automation, sensing and robotics
Topic: Thermal camera
Replies: 46
Views: 66851

Re: Thermal camera

CMOS and CCD sensors used in all normal cameras are based on silicon, which go blind at around 1100 nm. InGaAs based sensors are sensitive to much longer wavelengths, like 10-20 micrometers (10 000 nm - 20 000 nm) at which thermal radiation occurs. It's hard to make them so they cost a lot and long ...
by riklaunim
Tue Jun 17, 2014 6:50 pm
Forum: Automation, sensing and robotics
Topic: Thermal camera
Replies: 46
Views: 66851

Re: Thermal camera

You can use InGaAs photodiode (or few of them). Any InGaAs thermal imaging sensor on a board will be quite complex to operate, and very expensive. Depending on country military restrictions may also apply :)
by riklaunim
Tue Jun 17, 2014 4:37 pm
Forum: Camera board
Topic: Optimize dynamic range for security camera
Replies: 17
Views: 6749

Re: Optimize dynamic range for security camera

You can also stack multiple frames into one. That increases signal to noise ratio by square root of stacked frames count. That is used in astrophotography.
by riklaunim
Tue Jun 17, 2014 4:32 pm
Forum: Automation, sensing and robotics
Topic: Thermal camera
Replies: 46
Views: 66851

Re: Thermal camera

Note that real thermal cameras can cost like 10 000 EUR/USD or more. Sometimes low grade car thermal cameras can be found on ebay and alike for lower price.
by riklaunim
Tue Jun 17, 2014 4:12 pm
Forum: HATs and other add-ons
Topic: USB bar code scanner
Replies: 17
Views: 83338

Re: USB bar code scanner

You could try using some pyusb code to catch data from that scanner. You can get my code from that link. It converts those numbers to actual letters and digits from the bar code.
by riklaunim
Sun Jun 15, 2014 7:45 pm
Forum: Pidora / Fedora
Topic: Error Message Failed to fork (Cannot allocate memory)
Replies: 2
Views: 13506

Re: Error Message Failed to fork (Cannot allocate memory)

switch to terminal (like ctrl+alt+1), login and use "top" to see what's using most of the RAM. Some services may be stopped if not needed, or just disable X.org server and launch Python scripts from terminal.
by riklaunim
Thu Jun 12, 2014 11:22 pm
Forum: C/C++
Topic: calling c++ from python
Replies: 2
Views: 1431

Re: calling c++ from python

You could check if there is already a Python library for nRF24L01. If not you can expose C or C++ functions as a Python module. For C there are core Python example (using C "decorators" from Python to compile C as a Python module), and for C++ there are Boost example with their "decorators" to compi...
by riklaunim
Thu Jun 12, 2014 9:01 pm
Forum: Beginners
Topic: why wordpress response is slow at the respberrypi
Replies: 7
Views: 2486

Re: why wordpress response is slow at the respberrypi

WebPi wrote: That's how Pyplate works. It can generate pages dynamically, but it can also generate static HTML files. It makes a huge difference to performance.
Yes :) and Github Pages made even more of them so there is plenty to choose from. I've once seen a desktop one.
by riklaunim
Thu Jun 12, 2014 5:51 pm
Forum: General programming discussion
Topic: My LAMP Server
Replies: 3
Views: 1628

Re: My LAMP Server

There won't be one tutorial or one website to learn from. Website development is a very big area of IT knowledge. The key points are: - learn how to write good quality code (not just any code) - write small scripts that use what you are reading/learning about at a given time. Don't rush to write you...
by riklaunim
Thu Jun 12, 2014 5:41 pm
Forum: Beginners
Topic: why wordpress response is slow at the respberrypi
Replies: 7
Views: 2486

Re: why wordpress response is slow at the respberrypi

You would have to use one of those CMS that generate static web page out of dynamic "backend". RPi can't handle a typical full server stack with database and other services with very short response times. Static, pre-generated web page cuts the need for dynamic language execution and database operat...
by riklaunim
Thu Jun 12, 2014 5:28 pm
Forum: Off topic discussion
Topic: My idea for a flexible "Strawberry Pi"
Replies: 20
Views: 4666

Re: My idea for a flexible "Strawberry Pi"

Android irrelevant for education Chrome OS irrelevant for education more RAM , err no, the current configuration allows for all we want, and also requires frugality when programming, which is a good thing SATA irrelevant for education Ethernet it has Ethernet, works well enough for this purpouse. O...
by riklaunim
Thu Jun 12, 2014 5:24 am
Forum: Python
Topic: Calling php script from python- http 500 error
Replies: 1
Views: 1970

Re: Calling php script from python- http 500 error

Odd problem. You could try calling the PHP file locally (php-cli) and it that does't help - reimplement it in Python.
by riklaunim
Wed Jun 11, 2014 8:47 pm
Forum: Automation, sensing and robotics
Topic: hall effect sensor
Replies: 24
Views: 10500

Re: hall effect sensor

If you have it on a "Arduino" mini board then there are two power pins and one response (or two - digital and analog). Sensor on it's own has 3 pins and one of them will pass current if in magnetic field - will be just like a button, so you check if digital pin to which it's connected become "high".
by riklaunim
Wed Jun 11, 2014 6:11 am
Forum: Python
Topic: Plotting with Python
Replies: 4
Views: 1622

Re: Plotting with Python

There are various tutorials on the web (some here), it's a bit of work but it can be done quite easily actually.
by riklaunim
Tue Jun 10, 2014 11:48 pm
Forum: Python
Topic: Plotting with Python
Replies: 4
Views: 1622

Re: Plotting with Python

Update and display could be done by a PyQt4/5 desktop GUI application. It could spawn extra threads which would check if data changed and if so recreate the chart, which then would be displayed (image) by the application GUI.
by riklaunim
Tue Jun 10, 2014 5:19 pm
Forum: General discussion
Topic: raspberry pi satellite
Replies: 8
Views: 1091

Re: raspberry pi satellite

Electronics that is space-compatible costs a lot, while it may be a Core 2 Duo board ;) And in general electronics in space is heated to some temperature at which they work and don't fail. You may look at http://www.srl.utu.fi/AuxDOC/tke/radmon/cubesat_standard.pdf or http://www.intechopen.com/books...
by riklaunim
Tue Jun 10, 2014 4:26 pm
Forum: General discussion
Topic: raspberry pi satellite
Replies: 8
Views: 1091

Re: raspberry pi satellite

if put in a pressure vesicle could the raspberry pi be put in low Earth orbit to collect data. The key element is protection from radiation, protection from very low temperatures, then communication with ground based stations, permissions etc. Students often get access to CubeSat program - http://e...
by riklaunim
Mon Jun 09, 2014 11:00 pm
Forum: Off topic discussion
Topic: My idea for a flexible "Strawberry Pi"
Replies: 20
Views: 4666

Re: My idea for a flexible "Strawberry Pi"

for now you cannot make a truly "PI compatible" system without using the Broadcom BCM2835 SoC. good luck with trying to recreate that with an FPGA. For the GPIO you can. You just need the same set of GPIO and the same high level API/library for it. Like when I "ported" a Raspberry Pi library to con...
by riklaunim
Mon Jun 09, 2014 10:51 pm
Forum: Off topic discussion
Topic: My idea for a flexible "Strawberry Pi"
Replies: 20
Views: 4666

Re: My idea for a flexible "Strawberry Pi"

Just my idea ;)
by riklaunim
Mon Jun 09, 2014 10:07 pm
Forum: Off topic discussion
Topic: My idea for a flexible "Strawberry Pi"
Replies: 20
Views: 4666

My idea for a flexible "Strawberry Pi"

Raspberry Pi is popular, but there are constantly questions about Android, Chrome OS, more RAM, SATA, Ethernet, and what not. When Allwinner A20 single board computer decided to look and be somewhat compatible with Raspberry Pi all the blogs, social media went crazy and probably more people heard ab...
by riklaunim
Sun Jun 08, 2014 11:37 pm
Forum: Other programming languages
Topic: Recommendations for PHP IDE on Pi
Replies: 6
Views: 10814

Re: Recommendations for PHP IDE on Pi

Web project? :) Raspberry can't handle complex applications (+ web server to execute the PHP) so try something light like Kate or gedit for start.
by riklaunim
Sat Jun 07, 2014 11:39 am
Forum: Beginners
Topic: tesseract ocr
Replies: 2
Views: 629

Re: tesseract ocr

There are at least few Python tesseract wrappers. Most of them just call the tesseract binary - so you need both.
by riklaunim
Wed Jun 04, 2014 11:52 pm
Forum: Off topic discussion
Topic: Quad core development board
Replies: 19
Views: 5122

Re: Quad core development board

No, it does exist. I think Eben has taken a look at one (Foundation tend to buy in to see what the competition is doing). He wasn't particularly polite about it, and I cannot report what he said about it on a family friendly forum. Looks like he isn't used to buy from China :D Every electronics boa...
by riklaunim
Wed Jun 04, 2014 7:23 pm
Forum: Off topic discussion
Topic: Quad core development board
Replies: 19
Views: 5122

Re: Quad core development board

And it works, although no network just like on Android so I suspect the internal WiFi is boroken :P Time to use good old cables.
by riklaunim
Wed Jun 04, 2014 7:06 pm
Forum: Off topic discussion
Topic: Quad core development board
Replies: 19
Views: 5122

Re: Quad core development board

GPU is Mali400 which probably won't beat the VC4 however there is enough processing power to software render HEVC/H.265 video so can offset any shortfalls. If it's quad core Mali then it should easily overrun it but it's hard to compare as Mali shines in Android mostly. Plus it's tailored with much...

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