I am trying to send a serial command using my Arduino, but I can't find out how to replicate the Enter key. I've tried \r\n as well as \n and neither of those seem to do it.
I've tried the Arduino functions Serial.write() Serial.print() Serial.println() and none of those work either.
What can I use to replicate the Enter key?
Thank you
Try \r
It has the ASCII 0xD(13) and it's called Carriage Return
In general, it depends on the application that is processing the key press. From the keyboard, the typical scan code 0x1C is sent to the application for the Enter key (and 0x9C on release).
In PuTTY (related to OP's question here), it sends ASCII CR (carriage return) 0x0D only, even on Windows machines.
Related
Do you know if it is possible to have a device in between the keyboard and the computer , you press a recording key on the arduino, then press the letter P, the arduino keeps that P in memory and and the letter can be assigned to a rythm pattern and sent to the computer like this: P...P...P...PPPP..PP etc..
the information is received exactly the same way it comes in the computer with a physical keyboard.
the is a music based product as it is now the arduino can send midi to the computer and I would need a app to receive the midi data and convert it to keycode date so
I am looking at my other options to make the easiest system possible
Normaly keys are ASCII encoded so no need to get them from somewhere. So you could send over serial (usb) a char array either as ASCII characters
const char keyPresses[] = "P..P....P....P...P";
or ASCII encoded (depends on the Midi software used)
const uint8_t keyPresses[] = {80,,,80,,,80,,80};
To let the Arduino act like a keyboard (so the PC-SW is not aware that it is an Arduino) use the HID library, which has examples included for all kind of scenarios.To record a sequence of key presses a keylogger on the PCis the eseast way. Save to a txt file and copy and paste to the Arduino code or convert characters toASCII codes e.g. here online
I am sending commands over a serial port from a Linux embedded device to some serial enabled firmware. For easy debugging and simplicity we are using ascii human-readable commands terminated by newlines. Is it appropriate to use canonical mode here, or is canonical mode usually reserved for interactive terminals? The examples I find online all use raw mode.
In particular, in canonical mode, how do I check without blocking if an entire line is available for reading.
according to Linux Serial Programming documentation :
This is the normal processing mode for terminals, but can also be useful for
communicating with other dl input is processed in units of lines, which means
that a read will only return a full line of input. A line is by default
terminated by a NL (ASCII LF), an end of file, or an end of line character. A
CR (the DOS/Windows default end-of-line) will not terminate a line with the
default settings.
Canonical input processing can also handle the erase, delete word, and
reprint characters, translate CR to NL, etc..
First
using canonical mode for serial communications is the best option, because we have Linux kernel support on data transmission and system handlers that will help to better reading serial text
Second
if you want to use canonical mode , make sure that you are using the right character for end of line in your device that sending data , other way you cannot use canonical feature
Is it appropriate to use canonical mode here, or is canonical mode usually reserved for interactive terminals?
Yes, you can use canonical mode, but you will need to configure the termios interface for your situation.
The default termios configuration is for an interactive terminal, so features such as echoing the input should be disabled.
Since your device is unlikely to send the backspace and delete characters, such features can be ignored.
The examples I find online all use raw mode.
Seems like there are some "experts" that are not aware that canonical mode for terminals exists.
See the comments to reading from serial port in c breaks up lines .
For an example of (blocking) canonical mode, see this answer (note that there's another "expert comment" telling the OP that he cannot read lines).
In particular, in canonical mode, how do I check without blocking if an entire line is available for reading.
You could use select().
The man page implies that a canonical read of a terminal device is supported:
The file descriptors listed in readfds will be watched to see if characters become available for reading (more precisely, to see if a read will not block ...)
When both fields of the timeval structure are zero, then select() will not block and returns immediately.
I am working on GSM900A module and Arduino Uno R3.
I am getting output as following while sending an SMS using AT commands:
AT+CMGF=1
Ok
AT+CMGS="+91 10digit mobile number"
message
ERROR
And SMS is not sent to the particular 10 digit number. How can I overcome this problem.
The format to send sms is:
AT+CMGS=<number><CR>
<message><CTRL-Z>
Please check if you have added the carriage return after your number.
Also, you have to wait for > symbol before you type the message.
After the message is typed, give CTRL+Z.
You can find the equivalent ascii or hex values for these in ascii table.
amek sure there is no space between +91 and mobile number
I was also getting this errors because i did not enough power to gsm module. Make sure you are giving enough current. I think 2A should be fine
I would like to receive and send bytes that have special meaning in ASCII code like End of Text, End of Transmission etc. but I am not sure if it is allowed. Can it break my communication? Sending and receiving looks like reading from file that is why I doubt I can directly use this specific values. I use Windows OS.
EDIT: I have tested it and there is no problem with any sign. All of control ASCII characters can be sent via RS 232. Both reading and writing cause no unexpected behaviour.
RS232 is a very binary protocol. It does not even assume 8-bit bytes, let alone ASCII. The fact that on Windows, you use file functions does not matter either. Those too do not assume text data, although those do assume 8-bit byets.
RS-232 nodes do not interpret the data except in software flow control mode (XOn/XOff). You use this mode only if both parties agree and agree on the values of XOn and XOff.
The values are historically based on the ASCII DC1 and DC3 characters but the only thing that matters is their values, 0x11, and 0x13.
If you haven't set up software flow control, all values are passed through as-is.
I have an Arduino hanging off /dev/ttyUSB1, communicating at 115kbaud. The statements below work fine up to the 's next' method call, where Pharo hangs. The Arduino responds to the '99' command by sending a single character $1 back to the computer. If I pull out the cable, the program continues and s contains the character $1 just like it should, but not until I pull out the cable. So it's my impression that 's next' does not return after it reads just a single byte (ok, sure, there's nothing that says it should return after reading a single byte). How do I read a single byte from a stream in Pharo? Or how do I open a read/write byte stream? I haven't found anything in the source classes that seem to do this. I've tried setting the stream to ascii, to binary, to text, and it doesn't change the behavior.
s := FileStream oldFileNamed: '/dev/ttyUSB1'.
s readWrite.
s nextPutAll: '99'. "'99' is successfully received by Arduino"
s next. "hangs here"
s close.
Thanks for your help.
Take a look at the class side of FileStream. There you'll notice that you are getting a MultiByteStream (the concreteStream) when asking Filestream for an oldFileNamed:.
There can be a TextConverter or buffer involved. open:forWrite: of MultiByteStream is called, and that calls super. StandardFileStream>open:forWrite: calls enableReadBuffering.
You probably want to call disableReadBuffering on your stream.
There is an Arduino package that has all these issues solved, take a look at this repo:
http://ss3.gemstone.com/ss/Arduino.html