I want to know some general communication strategies, which should be followed for a communication via COM (serial) Port.
I can read/write at the port, also can list all the available ports on the machine. I'm using Qt C++ with QSerialDevice. For testing on a windows machine with no physical serial port, I'm using VPSE (virtual port)
Typical Flow (assumed):
List all the available serial ports of the computer.
Find out at which port my device (micro-controller) is connected - how to do it?
Device found.
Start a thread for reading from the port, another thread for writing it.
Safely close connection
Finding out at which port the device is connected sounds challenging to me. How to achieve it? I guess, I will send a HELLO message to each ports, if my device replies a specific per-defined reply message I can be sure my device is connected at that port. Can I?
Also I think, to seperate threads are necessary because at any time I may receive message from the Micro-controller device.
Thanks for helping :)
Related
Currently I have a server, that communicates with a projector through a RS232. The server opens a com port when the projector is connected. The same happens to any PC when a certain type of device is connected through the USB (lets say an Arduino for example). What I want to do it basically replace the projector with a PC/Arduino/Raspberry without the server noticing anything. That would mean the server will recognise the connected PC and open a COM port for it. What do I need to do on the PC so that it automatically opens a com port on the server? I guess there is something very basic that any printer, Arduino, projector etc does, that computers recognise it as a "com port device".
P.S. Doesn't matter the OS on the PC, I just need to make it work and then implement w/e I need to do with the established communication over the port.
P.S.2 I've searched a lot about it, but probabl I am doing it wrong, because I didn't find my type of question anywhere.
COM ports are basically hardware that is detected by the system. Let's say, if an Arduino is connected to a PC, it has its onboard USB to TTL converter which can be found in the device manager(if using windows). Similar USB to TTL converters are there in the market like CP2102, PL2303 which acts like a COM port even if no device is connected further to it. it may be possible that the program you are using(as you referred server) may be sending some data over the serial port and verifying the hardware.
What you need to do to replace it is, first of all, find the baud rate at which the communication is going on, then, listen over the serial lines which machine is sending which message in the sequence(there must be a handshake as I mentioned earlier), if a complicated algorithm is not used by the device, you can simply mimic the device by sending same messages over serial.
I have 16 Arduinos that are in very tight spaces and hard to get to when I need to reprogram them with my FTDI cable. I would like to have or create some sort of centralized place where I can connect my FTDI cable, make some sort of selection (switch of some sort), which will then connect the pins my cable is on to the selected arduino.
Does anyone have any thoughts on how this can be accomplished? I've toyed with transistors, but that takes a lot of them and didn't quite work.
Are there any premade solutions that are out there that I have yet to find?
Thanks very much!
Here is a thought! TCP to Serial.
Sound complicated.
Not really.
Note from AVRDUDE's manual the following
For programmers that attach to a serial port using some kind of higher
level protocol (as opposed to bit-bang style programmers), port can be
specified as net:host:port. In this case, instead of trying to open a
local device, a TCP network connection to (TCP) port on host is
established. The remote endpoint is assumed to be a terminal or
console server that connects the network stream to a local serial port
where the actual programmer has been attached to. The port is assumed
to be properly configured, for example using a transparent 8-bit data
connection without parity at 115200 Baud for a STK500.
With this, One could place your Arduino's behind your choice of TCP to Serial Server. Which is available in several forms. Cisco has a gang TS (but that is expensive, unless used). lantronix (and others have single end point devices. But then for Linux, there is "Net2Ser" which can serve up all your ttyS (aka Serial/COM ports).
With the later you could use a raspberry or TP-Link TL-WR703N (
In the latest IDE 1.5.6r2 add one entry for each TCP-to-Serial Port to ./Arduino/hardware/arduino/avr/programmers.txt file. While replacing the IP and Port with corresponding values.
TCP2001.name=TCP 2001
TCP2001.communication=serial
TCP2001.protocol=stk500v1
TCP2001.program.protocol=stk500v1
TCP2001.program.tool=avrdude
TCP2001.program.extra_params=-Pnet:192.168.1.100:2001
TCP2002.name=TCP 2002
TCP2002.communication=serial
TCP2002.protocol=stk500v1
TCP2002.program.protocol=stk500v1
TCP2002.program.tool=avrdude
TCP2002.program.extra_params=-Pnet:192.168.1.100:2002
...
Additionally change "protocol" to "upload.protocol" the following line in ./Arduino/hardware/arduino/avr/platform.txt
tools.avrdude.program.pattern="{cmd.path}" "-C{config.path}" {program.verbose} -p{build.mcu} -c{protocol} {program.extra_params} "-Uflash:w:{build.path}/{build.project_name}.hex:i"
to
tools.avrdude.program.pattern="{cmd.path}" "-C{config.path}" {program.verbose} -p{build.mcu} -c{upload.protocol} {program.extra_params} "-Uflash:w:{build.path}/{build.project_name}.hex:i"
With this you can use "Upload Using Programmer" with the selected programmer to send over TCP, rather then use the Upload.
That all said, it will only work on Linux.
avrdude: ser_open(): network connects are currently notimplemented for Win32 environments
Basically I have an Arduino UNO that I have connected via Ethernet to my router. I have logged the IP with my server and I would like to push data to my arduino. I guess the flow of data would be to send data (not sure the best way? Should I just open up a port and stream the data?) to the router that then forwards it to my Arduino at a local address assigned by my router.
How can I tell the router to forward this information on without logging in and changing anything with the router. The point of this exercise is to do everything with code and not do any other activities like logging into the router and setting things up. I want to do this as I have my Arduino recording temperature and I want to push data to state if it should switch sending the data from degrees or Fahrenheit or visa versa.
I would use a socket server with a publish/subscribe pattern. Probably several out there but I know XSockets.NET best.
A few hours ago I actually connected my Arduino to XSockets and communicated between webpages and my arduino both ways.
I will put the code on github when I am done, but you can look at a video showing the concept here: The Stuff For You Starts At 3:20
You dont need to open any ports as long as your arduino and server is on the same local network. Since IP adresses maps all devices on a network including your arduino.
The reason you want to open ports on your router is to make people outside your local network access a server on your network. Reasons why port forwarding exists is that when someone sends a packet of data to your public IP (which is your router) it doesent know which local IP to send the packet to. It then discards it, unless you port forward a port to a local IP, which means your router sends all packets with that port to that local IP adress.
You also need to make your own server program, for example a java program to act as a server.
I made something similar to what you are looking for, but i use a wifi shield instead. I've had some problems with maintaining connections with it, but so far it seems that it's a problem with the wifi libary.
You still might learn something from it though:
Maintaining communication between Arduino and Java program
If you want to know more about how the java server works in general, here is a great tutorial which explains a lot of the basics:
http://www.thenewboston.org/watch.php?cat=25&number=38
I am connecting to my USB modem on a COM port and sending him commands:
AT+CGDCONT=1,"IP","internet"
AT$QCPDPP=1,1,internet,internet
AT_OWANCALL=1,1,1
AT_OHCIP?
modem is answering and I can see that leda are lighting as where there is connection established. I took these command by sniffing communication between GlobeTrotter Connect and COM port. LEDS are the same in both situations. But in Control Panel connection named with GlobeTrotter HSxPA Network Interface #2 is offline (no connection). What am I doing wrong?
When I'm watching GlobeTrotter program and in the same moment watching commands there is no more commands sent. When I click Disconnect in appliaction (GlobeTrotter) in the same moment I see that status if Local Network is changed, but no command are sent. Maybe I should enable it in Windows in my program?
Thanks for any help
Do you know for sure that the internet connection initiated as a Dial-Up Network (DUN) connection and not as an USB ethernet connection? The reason I ask is because for DUN then all communication is done with AT commands and what you have captured should be enough to reproduce. If the connection is an ethernet connection the AT commands are more likely to be only for configuration.
Of the four commands listed, only the first is a standard 27.007 command. DUN with standard commands would typically have invoked AT+CGACT to activate the connection. Maybe the
AT_OWANCALL command is similar, although that is just wild guessing from the name on my part. You should try to get some documentation for these proprietary commands.
I'm creating a simple device that sends data to a Windows PC over serial COM ports.
I'd like the software to be able to scan the available COM ports until it recognizes the device. The problem is, if the PC tries to initiate the handshake with a device other than mine, it may interpret the commands [wrongly, of course].
The only solution I see is for my device to periodically broadcast some sort of identifier, perhaps 5 times per second or so, so the application only needs to listen for that identifier rather than risk corrupting another device also connected to a COM port. When the application loads, it listens on each available COM port until the device is recognised. Does this sound reasonable?
Thanks
IMO whatever the direction on which you initiate the handshake, the problem will be the same.
If you send your handshake from your device and another application on your PC is listening to the corresponding serial port, it also has risks to badly interpret the data you are sending.
So I would say that software on both side should be protected against incoherent data they receive from the outside.