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541  Using Arduino / Audio / Re: Arduino library for WTV020-SD-16P audio module on: June 15, 2013, 12:59:51 am
Hi the-rebel-agent,

Thanks for your library. Got my unit up and running in less that 30 minutes (most of it getting the wiring right!).

I had an old 64Mb(!) micro SD card that works fine and will probably be enough for what I want to do (voice for a robot).

542  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: June 14, 2013, 09:13:51 pm
The web site has been updated with an additional PDF file documenting the hardware BoM, component sources, and assembly of the PCB.
https://parola.codeplex.com
543  Using Arduino / Programming Questions / Re: what does #endif //ECHO_TO_SERIAL do in this code on: June 13, 2013, 08:55:04 pm
Strictly speaking it is not necessary. However, if you set the #define to 0, it has no effect on your code size as it is not compiled. If you ever need to debug the program you can turn it on again.

Having said that, there are probably better ways to do this that create less visual pollution in the code.
544  Using Arduino / Sensors / Re: Testing Color sensor on: June 13, 2013, 08:43:25 pm
I have a library that works well for these types of sensors in my code repository (link below in my signature).
545  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: June 10, 2013, 04:48:55 pm
The section of the video showing 'Scrolling' has 12 units daisy chained and working together. That's all the boards I have made up to date. At this stage I don't expect to be building up the remaining 8 spare PCB (I had 2 lots of 10 made up), but I can't see any issues arising from having more of the units connected. Any specific reason you see 10 as a limit?

I get my 8x8 matrices from eBay. The last lot I bought were from http://www.ebay.com.au/itm/230754163950?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649.

The controller chips come from Tayda Electronics http://www.taydaelectronics.com. They are about $1.25 each, so are probably not 'genuine' but seem to work perfectly well. Here is an interesting article about that http://tronixstuff.wordpress.com/2013/05/16/the-max7219-led-display-controller-real-or-fake/. I also get my passive components from Tayda.

546  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: June 09, 2013, 11:41:39 pm
Quote
If one set of female headers is replaced with female right angle headers,
http://www.karlssonrobotics.com/cart/6-pin-right-angle-female-header/?gclid=CLyetIbV2LcCFYyY4Aodsj8AWQ
then adjacent boards can be plugged together.

No doubt, but then with the joined units you have the matrix, the IC and then the next matrix. The matrices do not butt up against each other so, unless I am missing something, you can't build a continuous display (ie, matrix next to matrix next to matrix with no gaps).

Edit: for the sake of clarity I am not referring to the SMD units.
547  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: June 09, 2013, 10:39:21 pm
I did buy one of those larger units on eBay, as I started out wanting to use these 'off the shelf' type - they are pretty cheap. The problem (for me at least) is that the connections do not allow them to be joined up without cables. My design is similar but has connectors on the edges so the modules can be just plugged together.

The SMD units are more like where I would like to be at, but they are too expensive for my budget.

548  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: June 09, 2013, 08:59:21 pm
Thanks Pedro. I am sure that it could do a lot more but I have run out of interest at the moment and want to move on to something else. Maybe if others write effects they can be built into a future release ...

Documentation is included with the library in the docs folder as an html file.

Boards are not 'for sale' as such, but it is easy enough to use the SeedStudio files to have some made. It is actually quite cheap (about AUS$15 delivered to Australia) for 10 boards, so if you have not tried doing this before, give it a go. Takes about 2 weeks from order to postman delivering.
549  Community / Exhibition / Gallery / Re: Scrolling LED matrix display - Parola for Arduino on: June 09, 2013, 01:27:06 am
Thanks. I started with the DX/eBay modules as well but they have the connector on the wrong edge so I designed my own.
550  Using Arduino / LEDs and Multiplexing / Text display project completed on: June 08, 2013, 11:42:30 pm
If you are a regular on this forum you may be interested in my latest project which is a modular scrolling text display using MAX7219/21 LED matrix display controllers. The display is made up of any number of identical modules that are plugged together to create a wider/longer display.

Main post is at http://forum.arduino.cc/index.php?topic=171056.0
551  Community / Exhibition / Gallery / Scrolling LED matrix display - Parola for Arduino on: June 08, 2013, 11:39:44 pm
My latest project is a scrolling text display.

Parola is a modular scrolling text display using MAX7219/21 LED matrix display controllers. The display is made up of any number of identical modules that are plugged together to create a wider/longer display.

The aim was to create a 'lego-like' approach to LED matrix display, using standard 8x8 LED matrices. The software supports this flexibility through a scalable approach that only requires the definition of the number of modules to adapt existing software to a new configuration.

The library implements functions to simplify the implementation of text special effects on the LED matrix.
  * Text left, right or center justification in the display
  * Text scrolling, appearance and disappearance effects
  * Control display parameters and animation speed
  * Support for hardware SPI interface

Hardware and software are available at http://parola.codeplex.com.
A video of the system working at http://www.youtube.com/watch?v=JgzVCSFaz3I&feature=youtu.be
552  Using Arduino / Sensors / Re: Color Sensors on: June 06, 2013, 09:59:55 pm
I did some work with the TSC230 color sensor a while ago. The library and pdf on how to use the sensor (calibrated) may be helpful. Link is in my signature below.
553  Using Arduino / LEDs and Multiplexing / Re: I'm stuck in ledControl and a Max7219 board. (Solved) on: June 06, 2013, 09:54:29 pm
I am still amazed at how the most obvious things take time to fix because they are hiding in plain sight!
554  Using Arduino / LEDs and Multiplexing / Re: I'm stuck in ledControl and a Max7219 board. (Partly solved) on: June 06, 2013, 02:26:42 am
Every time you exit loop() and re-enter, the variables are recreated.

However, what does make some sense is that the variables will occupy the same location as there is nothing else happening between calls (ie, they are recreated in the same order). Unless the number is negative, the variable is actually not initialised to false and keeps wahtever the value was when it was created. Try changing the variable declaration to

Code:
boolean negative = false;
555  Using Arduino / Programming Questions / Re: Help With TCS3200 Color Sensor (Understanding Output) on: June 05, 2013, 04:59:15 pm
I didn't take averages because I found that the readings I got back were identical, surprisingly, but that meant that one reading was enough. I guess that is because we are counting pulses over a relatively (in computer terms) long time.

Whether you need Fd depends on how you apply the sensor. With my sensor Fd was 2-5% of the full range, depending on the filter applied (R, G or B). If you are only trying to measure relativity between samples (ie, something is more 'red' or 'green' than something else) then ignoring Fd is fine, as the sensor's linearity will give you what you need.

However, if you are trying to find the actual RGB colour of a sample, then Fd becomes important. The mappings I was getting were close to the colour's RGB number, but in some cases the 'look' of that colour was very different. Adding the Fd correction fixed that up.

Fd is also useful for correction of your background is not 'black' as the background will contribute to the colour you are trying to measure.
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