I need to develop a service that will actively find new serial devices connected and spin a new thread for that serial device
The main reason is that we have a unix machine (some places a mac, others a linux and some even a raspberryPi). This machine will have many devices connected (external HDDs, Arduino(s) and phones, etc).
The software will look for all serial ports and find the arduinos connected, then it will spin a thread to handle that arduino.
Our problems are:
List only serial devices in any platform
On mac is /dev/tty.(any name here)
On linux is /dev/ttyUSB(#)
Detect only the arduinos
Some devices are listed as ttyUSB and others as ttyModem or even ttyACM
In linux i could create a udev rule, but on mac i didn't find a way
The sigrok project has a subproject called libserialport for finding devices on serial ports on the different operating systems.
http://sigrok.org/wiki/Libserialport
Related
What I want to do:
An AI program on a host machine, reading inputs from a camera sensing the screen of the target machine and outputting controls to the target machine via USB connection--programming the host machine's USB host as a USB peripheral connected to the target machine.
What I want to do step by step: (is it possible to implement the steps below?)
Have a host machine A and a target machine B.
Connect A and B with a USB 3.0 Type-A male-male cable.
The USB connection shows up as an HID keyboard device on B.
Write code to simulate key presses on A that sends to B.
(Eg. calling press('F') on a program running on A would type F to B's input)
It shouldn't require any program installed on B.
What I already searched:
USB 3.0 Host to host connection is possible:
https://superuser.com/questions/795053/how-do-i-connect-two-computers-using-usb-3-0
USB 2.0 Host to host connection is impossible:
https://superuser.com/questions/99274/how-to-connect-two-computers-with-usb
Similar questions asked without the assumption that USB 3.0 Host to Host connection is possible:
https://superuser.com/questions/1128365/simulate-usb-keyboard-from-machine
Setting up a computer to act as an HID device connected to another computer via ps/2,usb or another wired connection
https://superuser.com/questions/507921/computer-to-act-as-keyboard?rq=1
Suggestions in ascending order of feasibility:
USB Gadgets
You are using linux, so the default way would be to create/configure/load a gadget driver. Have a look at this tutorial, though for a raspberry, should work on your PC too. However, I could not find any information regarding the use of USB3 - the tutorial assumes your host is using one of it's OTG ports, which your PC most likely does not have. So whether this works with your USB3.1 Type-A-to-Type-A connection you'll need to test.
USBIP
The idea of sharing USB devices (not just keyboards) is not really new. With USBIP you can "export" any local USB device to the network, and your client will need the client-side USBIP driver to access the keyboard.
Dont bother with USB at all, just use Ethernet
I'd simply write two userland scripts/programs that send/receive+execute the keystrokes. Very easy to implement, you're probably familiar with python anyway.
If you absolutely cant have software installed on the client-PC and your Type-C-to-Type-C connection doesnt support USB Gadgets, there's another way. It basically involves the use of two USB-to-serial adapters (~15$) and a serial cable. While this wont be enumerated as a keyboard, but rather as serial port, it's the lowest-effort solution to transfer data without additional software on the client. Both computers will just do file I/O. If your computers still have COM-ports, you can even omit the serial converters!
I have multiple ACR122T smart card devices with no unique serial numbers (from ACS). I need to know which physical smart card I am connected to from within pcsc-lite. I know from using lsusb which USB Port a physical device is on, but how to map that USB port information with SCardGetAttribute(SCARD_ATTR_DEVICE_UNIT) ?
It seems the map should be at the OS level as I cant find a way to read USB Port info (lsusb results) from within the pscs-lite API.
This post mentions a method, Smartcard reader ACR122U has no unique serial number
but I dont understand the details behind "used that dev number to ensure I always used the right reader".
Any help appreciated.
Thanks, -Phil
Disclaimer: I'm working on Windows, not Linux.
The ACR122T (and ACR122U) devices not only have no serial number (other than the one printed on the back) but also have no USB serial number so that they can only be differentiated by the USB port they are plugged in. Additionally all the ACR122Ts and Us I have here (we bought a bunch) identify themselves as "ACS ACR122" to Windows. Using the proprietary API to get the firmware version both the ACR122T and the ACR122U identify themselves as a ACR122U (e.g. "ACR122U207" or "ACR122U214").
That means that the OS itself is not able to differentiate multiple devices in any other way then the USB port it's plugged in.
I also tried to make a connection between the pcsc device and the OS device, but apart from this function (which is only available starting Windows 8) I have not found anything, so it looks to me like there is no way to do that through pcsc calls.
The device unit is given out by the pcsc layer sequentially so you can differentiate between devices you are connected to but not identify a specific device.
Is there a way to use one computer to send keystrokes to another by usb ?
What i'm looking to do is to capture the usb signal used by a keyboard (with USBTrace for example) and use it with PC-1 to send it to PC-2.
So that PC-2 reconize it as a regular keyboard input.
Some leads to do this would be very appreciated.
What you essentially need is a USB port on PC-1 that will act as a USB device for PC-2.
That is not possible for the vast majority of PC systems because USB is an asymmetric bus, with a host/device (or master/slave, if you wish) architecture. USB controllers (and their ports) on most PCs can only work in host mode and cannot simulate a device.
That is the reason that you cannot network computers through USB without a special cable with specialised electronics.
The only exception is if you somehow have a PC that supports the USB On-The-Go standard that allows for a USB port to act in both host and device mode. USB-OTG devices do exist, but they are usually embedded devices (smartphones etc). I don't know if there is a way to add a USB-OTG port to a commodity PC.
EDIT:
If you do not need a keyboard before the OS on PC-2 boots, you might be able to use a pair of USB Bluetooth dongles - one on each PC. You'd have to use specialised software on PC-1, but it is definitely possible - I've already seen a possible implementation on Linux, and I am reasonably certain that there must be one for Windows. You will also need Bluetooth HID drivers on PC-2, if they are not already installed.
On a different note, have you considered a purely software/network solution such as TightVNC?
There is a solution:
https://github.com/Flowm/etherkey
This uses a network connection from your computer to the raspi which is connected to a teensy (usb developer board) to send the key strokes.
This solution is not an out-of-the-box product. The required skill is similar to programming some other devices like arduino. But it's a complete and working setup.
The cheapest options are commercial microcontrollers (eg arduino platform, pic, etc) or ready built usb keyboard controllers (eg i-pac, arcade controllers,etc)
SEARCH THIS PROGRAM:
TWedge: Keyboard Wedge Software (RS232, Serial, TCP, Bluetooth)
then, MAKE YOUR OWN CONNECTION CABLE WITH:
(usb <-> rs232) + (NULL MODEM) + (rs232 <-> usb)
Connect 2 computer, write your own program to send signal to your (usb <-> rs232) unit, then you can control another computer under the help of TWedge.
The above mentionned https://github.com/Flowm/etherkey is one way. The keyboard is emulated from an rPi, but the principle can be used from PC to PC (or Mac to Whatever). The core answer to your question is to use an OTG-capable chip, and then you control this chip via a USB-serial adapter.
https://euer.krebsco.de/a-software-kvm-switch.html
uses a very similar method, using an Arduino instead of the Teensy.
The generic answer is: you need an OTG capable, or slave capable device: Arduino, Teensy, Pi 0 (either from Rapberry or Orange brands, both work; only the ZERO models are OTG capable), or, an rPi-A with heavy customisation (since it does not include USB hub, it can theoretically be converted into a slave; never found any public tutorial to do it), or any smartphone (Samsung, Nokia, HTC, Oukitel ... most smartphones are OTG capable). If you go for a Pi or a phone, then, you want to dig around USB Gadget. Cheaper solutions (Arduino/Teensy) need custom firmware.
I have a USB to parallel port device that i want to interface with through c++ on a modern windows OS (xp and newer).
I've done a little research but the information is a bit patchy when it comes to programming to one of these USB to parallel port devices (most of the information is dated and assumes that you have a parallel port built right into the motherboard, something my brand new computer doesn't have). One reference even says that it is not possible to interface with a USB to parallel port from a C++ program without some sort of software changes.
All i want to do is to is be able to read or write 8 bits to the parallel port through a USB to parallel port device on a modern computer running a modern windows OS (with ports being dedicated to reading or writing only).
Is there any quick and easy way of doing this? Some sample code would be greatly appreciated.
Also, how many of these USB to parallel ports can I interface with my computer? Am i limited to 3 due to some sort of legacy addressing or can i have as many as my USB and CPU are able to support?
Working off VC++ 2008, running Windows 7 x64 with a Core i7 860.
Edit: a bit more information...
I've tried using inpout23 along with some prewritten test program. It compiled just fine and ran just fine claiming to have both read and written to a parallel port. I had my USB to parallel port connected to the computer and that port connected to a cable in which i had identified, stripped and soldered each of the 25 wires onto a sort of plug for quickly plugging into a breadboard for testing. None of the output pins had changed to what the program had said was written to them (instead they were all set to high and never changed).
I've done this in the past and I have good news and bad news.
The good news is that it always worked (sometimes with tweaking), which is a tribute to the electronic manufacturers of designing extremely robust protocols. Apparently the USB to parallel converters all provided the hardware port emulation.
The bad news is that performance was awful on the 'bitbanging' interface models. If you do not mind slow updates this is not an issue at all. I used it for programming uControllers and soon the price of serial or USB programmers was overcome by my impatience.
Just use the windows API to read/write the LPT or COM ports and it works (slowly).
I've worked with a USB-to-serial port adapter before and I guess USB-to-parallel should be the same. You should have got a driver along with the adapter - this does most of the work for you, hiding the USB interface and presenting it to the OS as a traditional parallel port. For example, when I plug my adapter into the USB port, it just shows up as COM4 in Device Manager. I'm guessing yours will show up as LPT1 or something. From there on, it's a matter of using the standard Windows API to access these ports. (see Communications Resources on MSDN)
Misteriously I succeed with the USB to LPT-DB25 Wire bought in ebay.com.
We should connect a LED between the /LF Line Feed and GND pins.
After discard the USB registers in order to find that one associated to the USB Cable, we should build an API (Application Programming Interface) to interact with the outputs/Registers.
I'm going to try to attach a picture to have a look how I managed it:
Is there any simulation environment that allows to run and test Linux based USB device application on host machine running Linux?
Also same thing for Linux based USB host side applications where one can run and test Linux based host applications with physical/virtual USB devices.
Regards,
Mooni
Are you asking if it's possible to use a general purpose PC to simulate a USB device? If so, no, the hardware on, say, your motherboard is not physically capable (in almost all cases) of emulating a USB client device.