I got an assignment at work to create a system which will be able to direct sound to different output channels of our sound card. We are using M-Audio ProFire 610, which has 8 channel output and connects through FireWire. We are also using a Mac Mini as our host server and I'm gonna be working in Xcode.
This is the diagram of what I am building:
diagram http://img121.imageshack.us/img121/7865/diagramy.png
At first I thought that Java will be enough for this project, however later on I discovered that Java is not able to push sound to other than default output channels of the sound card so I decided to switch to C++. The problem is that I am a web developer and I don't have any experience in this language whatsoever - that is why I am looking for help from more experienced developers.
I found a Core Audio Primer for ios4 but not sure how much of it I can use for my project. I find it a bit confusing, too.
What steps should I take to complete this assignment? What frameworks should I use? Any code examples? I am looking for any help, hints, tips - well anything that will help me complete this project.
If you're just looking for audio pass-through, you might want to look at something that's already been built, like Jack which creates a software audio device that looks and works just like a real one (you can set it as default output for your app) and then allows you to route each channel anywhere you want (including to other applications).
If you want/need to make your own, definitely go with C++, for which there are many many tutorials (I learned from cplusplus.com). CoreAudio is the low-level C/C++ interface as Justin mentioned, but it's really hard to learn and use. A much simpler API is provided by PortAudio, for which I've worked a bit on the Mac implementation. Look at the tutorials there, make something similar for default input and output, and then to do the channel mapping use PaMacCore_SetupChannelMap, which is described here. You'll need to call it twice, once for the input stream and once for the output stream. Join the mailing list for PortAudio if you need more advice! Good luck!
the primary APIs are at CoreAudio/AudioHardware.h
most of the samples/supporting code provided by apple is in C++. however, the APIs are totally C (don't know if that helps you or not).
you'll want to access the Hardware Abstraction Layer (aka HAL), more details in this doc:
http://developer.apple.com/documentation/MusicAudio/Conceptual/CoreAudioOverview/CoreAudioOverview.pdf
for (a rather significant amount of) additional samples/usage, see $DEVELOPER_DIR/Extras/CoreAudio/
Related
I did my best to search all topics regarding to SCADA and developing your own C++ desktop application to communicate with PLCs, but could not find any recent, or in my opinion, relevant topics that fit what I needed. If I missed them, a link to them would be very much appreciated. If I also happened to post this in the wrong section, or you can think of a better section for me to post this in, I will take it there.
With that said, I thank you in advance for taking the time to read my questions, and appreciate any input you have to offer.
A little bit about what I'm doing
I'm currently in school for electromechanical engineering, and for my final year project I am developing a desktop application in C++ to monitor PLCs we have located within one of our labs.
Within this lab, I have a pre-existing ethernet network connecting all PLCs to single point, which I am tying into with a PC, and will be doing all my work from there.
I will be developing the application in Qt for an easy way to design the GUI, and giving me access to the QNetworkInterface as well as QTcpSocket.
With that said, I wouldn't go as far as saying I'm an experienced programmer, but I have been fooling around with a few languages (i.e.: python, c++, c, php) for quite a few years, and am still learning, considering the learning NEVER stops.
My questions
Is there any reference material I can read, that you can suggest, on the subject to more easily understand what sort of process I need to go through to receive information (i.e.: individual I/Os, status bits, tags, logs, etc...) from the PLCs directly, and not through an OPC server?
If an OPC server is required, I've never dealt with OPC links other than using Rockwell Automations RSLinx to grab tags and display their values within excel (I had created a prototype using that exact method to start, but would like to move away from excel, and if possible, the OPC server (RSLinx) as well). What would you suggest to someone who knows nothing about the subject of OPC servers, or to my knowledge, OPC in general?
Have any of you previously written your own application to do something similar, if not of the same nature to what I'm trying to accomplish?
What advice or suggestions would you give for someone who is attempting this type of project?
PS: As a start for this project, I would initially just want to get the reading of the I/Os (tags or addresses) to view what their current values are (closed or open for inputs, energized or not for outputs). But eventually I would also like to be able to write values to tags on the PLCs I'm monitoring based on the values I've received from them.
PSS: I would like to note again, that I am still a student, and am still learning about this subject in it's entirety. I would just like to ask for your patience, as I may not grasp things completely the first time!
If I've missed any information you feel is pertinent to be able to provide an answer, please let me know! I will do my best to come up with said information in a timely manner!
Thank you!
EDIT #1: Added in another question, and altered my first question slightly
EDIT #2: Fixed up question 2
IMHO a SCADA program should have as a minimum requirement to be able to connect to an OPC server. OPC is used for most commercial PLCs.
Strictly speaking there is no need to have an OPC server/client approach but it gives you flexibility and gives you an abstraction model. If you want to directly connect to PLCs using a protocol then that is of course possible as well. You then need to know more details about the protocols and their various versions.
Yes I worked for a few years in a team that developed a commercial SCADA application.
It is very easy to get lost in details in such a project so try to keep things as simple as possible. By using OPC you will save time instead of fiddling directly with the protocols. You could add the ability to add custom-drivers for other protocols - depending on your timeframe. Try to model up your project before you start coding to a birdsview of the model and avoid getting lost in the details.
I would stay well away from looking to write your own code to connect directly
to an AB PLC - there are products out there that you can use in your application:
http://www.rtaautomation.com/software/ethernetip/client/tagc/ControlWin.html
http://www.automatedsolutions.com/products/dotnet/ascomm/
You would be better to use OPC - you can write you own OPC client if you want and follow examples you find here:
http://www.opcconnect.com/source.php#freesource
According to this http://www.control.com/thread/1026173407 you should be able to get source code of Kepwares OPC Quick Client.
It would probably be easier to just use a library as in this example (RSLogix,C#):
http://www.mesta-automation.com/opc-client-with-c-an-how-to-video/
You might find this of use:
http://www.rockwellautomation.co.kr/applications/gs/ap/GSKR.nsf/files/rslinxsdk_ma_eng.pdf/$file/rslinxsdk_ma_eng.pdf
Some resources:
http://www.opcconnect.com/ ,
http://www.mesta-automation.com/
Answer to question #4 - realize that your lab technically could contain ANY manufacturer's PLCs in the future. If you ever took a Data Communications class, you realize that for N different PLC types, you would have to write N different communication drivers for your PLC client.
This is where standards are helpful. Without the use of a standard protocol, scaling your lab could become more time consuming and less manageable. This is why communications standards exist.
HOWEVER, not all PLCs necessarily support the standard(s) you may decide upon.
The best choice is OPC/UA. Many PLCs have server drivers readily available. That means that your client just needs to understand 1 protocol (OPC/UA), and then it can "easily" be connected to any PLC that has a driver for that standard.
After that, there is OPC. After that, Modbus (TCP and RTU flavors), a relatively simple industry standard that is supported by most PLCs. EtherNet/IP is also a possible choice, although not all PLCs support it in a "server" role (many do support it as a client, but that is not what you need).
have a look at pycomm in github or pylogix at github which are Python written drivers to link to clx plc.
I've received a dk 3200 kit recently. I know it's old but I would like to start using it to have more of a challenge than just arduino. It came with the board, an st flashlink FL-101B and some cables. I do not have the install disc, but I found the software for psd soft express online. It doesn't work with current windows 7 64bit. If I could use my arduino to program it, that would be great! Or maybe just do it through USB or the parallel ports? I've read that st provides a stm32 library used to help make code. If that works for my mcu, I'll use that.
Thanks
ST is a company that loves to re-organize their website and break links, but a data sheet for a part of what seems to be the same family as on your board is available from a toolchain vendor at:
http://www.keil.com/dd/docs/datashts/st/upsd321x_ds.pdf
On page 118 this seems to indicate that programs can be loaded using JTAG In System Configuration commands, which may be somewhat standardized though quick searching isn't producing a lot of leads. A reference is also made to ST's AN1153 which would be worth trying to locate a copy of, however it's not entirely clear if that will say anything about the programming, or if it only covers the additional two optional signals which have been added for hardware acceleration of the interface.
In theory, if you can find sufficient information about this device (looking at related devices may provide clues) then you should be able to craft a programming from an Arduino or anything else that can be adapted to twiddle bits at the appropriate voltage/threshold levels.
In practice, you may be better off trying to find an old Windows XP box, or even trying to run that software on a virtual/emulated environment and trap the I/O access either to proxy or to figure out what it is doing and reverse engineer your own programmer.
But unless you have a large installed base of boards using these chips, or particular need some unusual feature of them (I thought I saw something about a built-in CPLD?) it's really not going to be worth the effort.
For some time now I've been tossing around what I think is am awesome idea: I want to write essentially a C++ phone server to handle all of my incoming calls on a land-line. I'll have a white-list (yay never having to worry about telemarketers ever again!), a black-list, and will be able to access my phone using my gaming headset, allowing me to make/answer calls while I'm gaming or whatever. In the future I'd also like to hook it up to a gui and make it have pop-ups and other cool features.
The problem is, I have no idea where to start. I'm familiar enough with C++, but have no idea how to go about doing anything with a phone-line. I can plug a phone-line into my computer, but I have no idea how to get my program to be able to use that connection. There's WinSock2 for being able to use my ethernet connection, is there something similar I'd be able to use to use the phone line? As it's using the same ethernet jack, I wonder if it's even possible to use WinSock2 to use the phone-line?
I saw this post, which wasn't particularly helpful: stackoverflow link , which points out Dual-tone multi-frequency signaling. I stumbled across this site: link, but isn't really going to help me get started.
So I was wondering, is there some sort of library out there that would allow me to tap into a phone-line that's connected to my computer? Is there a standard somewhere out there concerning phone-lines and what the different combinations of tone's mean? Can anyone here help get me started? I realize it's somewhat of a big undertaking, so any push in the right direction would be greatly appreciated. Thanks.
[Update:]
I found this question, which is a step in the right direction, but I'm not sure yet if it helps me (I need to go to bed, and will take a look at it in the morning). I did see mention of a Microsoft Telephony API though, I'll try doing more research on that tomorrow.
If working with MS products is not an absolute necessity, you might also consider taking a shot at Asterisk. This is an open-source PBX (in software) that allows development on Linux, Windows (emulated) and Mac. At the company where I work, we use it for implementing small-scale exchanges, about a 100 lines or so. It also interfaces well with VoIP and allows a whole host of protocols. I have developed scripts and programs in C++ that work on voice packets in real-time, and so far, my experience has been good. As for your stated use-case of blocking telemarketers etc., this would be a very good fit. Check out further details here.
After doing more research, having one link lead to another link, and coming up with new search terms, I stumbled across this site that looks like it could kick me off using the Windows Telephony API in C++: link. This link includes open source c++ samples showing how to do the basics of what this question asks, I'll just have to test to see if they actually still work.
This is only the beginning of my research, so I'll keep you posted on any other findings. If anyone else is knowledgeable in this area, please still feel free to drop me information on what I want to accomplish.
A while back, I got a LEGO Mindstorms NXT set for Christmas, and now I would like to program it in C++.
I have looked around, here and other places, and could not find a cross-platform, open source, OOP C++ library that "felt right", including lestat and nxtOSEK.
So, I have decided that unless I can find one I do like, then it would be a great learning experience for me to write my own library.
I have done a little research, and decided it would be easiest to communicate with it over bluetooth, rather than compiling my programs to the NXT machine code.
I would also like this to be done in OOP style, meaning the NXT brick, motors, sensors, etc would exist as objects.
So, my question is: what do I need to know before embarking on this? where can I get good references (besides here, and specific to the NXT)? What are other decent "basic" libraries* for things like Bluetooth communication?
*I am all for using boost and the STL, if necessary, by the way.
Alternatively, I believe in not reinventing the wheel if I don't have to, so if there is a decent C++ OOP bluetooth-communicating NXT library out there, let me know!
I've taken a look at doing this before.
Start looking here: http://bricxcc.sourceforge.net/
On this page you can download the source for it. What I ended up doing is compiling my C source code down to byte codes that the NXT brick can understand.
This allowed me to add some custom extensions to C though I did spend alot of time compiling C down to a compact enough form in byte codes that fit into the NXT's memory:)
If you want to use an existing C implementation then check out this chart: http://www.teamhassenplug.org/NXT/NXTSoftware.html
For a list of the NBC(Next Byte Codes) start with this page. I found it extremely helpful.
http://bricxcc.sourceforge.net/nbc/
I used this one, I don't know whether you have checked it out or not:
http://www.norgesgade14.dk/bluetoothlibrary.php
This library provides support for reading various sensor data over a bluetooth connection as well as support for controlling motors.
Moreover the library can be easily modified, and I found it extremely easy to reconfigure it.
I came across this thread last year, while working on a project using C++ to control a robot arm. I used 2 NXT bricks and 5 motors.
You can find the original NXT++ 0.6 library here:
http://nxtpp.clustur.com
https://sourceforge.net/projects/nxtpp/forums/
Unfortunately this site is not being updated.
I forked a new version NXT++ 0.7 with some fixes, and support for multiple bricks, via USB or Bluetooth:
https://github.com/dbworth/nxt-plus-plus
See the Readme file for details.
Another user, Piotr, has added support to NXT++ 0.6-2 for the HiTechnic sensor multiplexor and Lego color sensor:
http://wmii.uwm.edu.pl/~artem/downloads.html
Regards,
David.
Lets see the demonstration of possibilities of NXT++, the histogram filtering,
https://www.youtube.com/watch?v=PDYtjWgvsxg
it is based on the latest version supporting multiplexers,
from http://wmii.uwm.edu.pl/~artem and download section,
When I started using SoundEngine (from CrashLanding and TouchFighter), I had read about a few people recommending not to use it, for it was, according to them, not stable enough. Still it was the only solution I knew of to play sounds with pitch and position control without learning C++ and OpenAL, so I ignored the warnings and went on with it.
But now I'm starting to worry. The 2.2 SDK introduced AVFoundation. Using both SoundEngine from CrashLanding (for sounds) and AVAudioPlayer (for music), I found out SoundEngine behaves strangely when the only existing AVAudioPlayer is released (all sounds stop until a new AVAudioPlayer is initiated). Around the same time as the 2.2 SDK came out, the CrashLanding sample code was mysteriously removed from the ADC site. I'm worried there are more bad surprises to come.
My question is, is anyone aware of an Open Source alternative to SoundEngine? Maybe even a C++ library that uses OpenAL?
Look at this library, but i don't know is this what you need.
The Kowalski project provides a data driven and portable sound engine that currently runs on iOS, OS X and Windows. The engine is released under the zlib license and provides positional audio, pitch control etc.
ObjectAL for iPhone
Clone it. Use it. Love it. Enjoy the freedom.
Why not just use AVFoundation? It's pretty simple to handle and nicely flexible - apart from if you need exact timing (says the Apple documentation - but I've been testing it fairly extensively and yet to find any significant practical issues) I don't see any reason for not leveraging it.
AVFoundation lacks sound placement. This makes me sad.
I’ve written a simple sound engine around OpenAL. There are no position controls (I didn’t need them), but they would be trivial to add if you find the rest to your liking. And there is also some experimental sound code in the Cocos2D engine. It has both pitch and position controls and looks quite usable.