I want to transfer a number from java program which is on laptop (means there is no rs232 protocol pin is provided) to a pic microcontroller(where essentially I have to used rs232) .Therefore here I require usb /rsr232 converter.
Which Java library should I use ?
Will it work with javax.comm library?
The answer is it depends on the USB/RS232 converter you are using. Most that I have used will expose the serial port as a virtual com port device on your operating system (see page 8 of this PDF document). If that's the case, javax.comm will work fine. If not, you will have to use a proprietary API for the hardware which should be provided by the manufacturer. If you have hardware like this, I would strongly recommend replacing it with a class-compatible USB device.
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Over the last couple of years I have been looking for an easy way to control a few relays from Javascript. I want to build a web App to control starting sequence horns for sailing races.
I recently discovered webUSB and it seems like exactly what I need. A direct connection from JS in chrome to the USB world. Simple coding in a language I already use.
On the hardware side I am having trouble finding a product that is compatible. Googling USB Relay finds 100's of products that all seem to rely on some proprietary SW for the OS. I can find lots of educational demo's that turn an LED on and off.
Does anyone have any ideas where to find such a product?
While I'm sure you will be able to find USB relays that can be controlled via WebUSB, most USB relays will probably come with some kind of serial port driver, e.g. https://numato.com/product/1-channel-usb-powered-relay-module uses a CDC serial port driver. These can be controlled using Web Serial, available in Chrome 77 and later behind a feature flag. For a tutorial, see https://codelabs.developers.google.com/codelabs/web-serial/
Explainer: https://github.com/WICG/serial/blob/gh-pages/EXPLAINER.md
API docs: https://wicg.github.io/serial/
If you search for "5V USB Relay Programmable Computer Control For Smart Home" on eBay, you will also find low-cost relays that use HID instead. The advantage of these is that you don't need any serial port or USB drivers, as it will use the operating system's built-in HID drivers. For that you can use WebHID. For more info, see https://github.com/robatwilliams/awesome-webhid.
I have a WPF desktop application that would make a good candidate as a Universal Windows App. The application has a must-have dependence on USB or Bluetooth devices that act as a Serial Port.
In all my reading I've yet to discover whether there is any access to a SerialPort API in a UWA.
I suspect the answer is 'No support'. If so, does anyone know of a USB or Bluetooth GPS that supports whatever APIs the UWA has for that sort of thing. I have to be able to read things like ground speed, elevation, rate of climb, etc.
If the answer is 'Supported', could you point me to some documentation.
For the "Bluetooth devices that act as a Serial Port", I assume you mean the RFCOMM. They are both supported on Windows Runtime since Windows 8.1 and you can also use them in the Universal Windows Application.
namespace: Windows.Devices.Usb and Windows.Devices.Bluetooth.Rfcomm.
About the Bluetooth GPS, I'm not sure if it uses RFCOMM or not (it depends on the devices), and it is also possible to use the GATT.
Code Sample: Custom USB device access sample
I'm currently working on a device which is able to work as a keyboard and communicate via Serial with a self-written software.
Now I have to install serial drivers (from Arduino) on different computers if I want to communicate with my application which I actually want to avoid.
Is there any other solution to solve this problem? Is it possible that my microcontroller works as a keyboard AND is able to send and receive data as HID device?
Thanks and greetings!
I actually do something similar with a 32u4, but it receives its serial over the built-in UART. I do this because it's linking between two separate systems. If it were only one system I could implement a 2nd interface. (Don't forget, a USB HID device must have an IN endpoint even if you are not using it.) Or you could just throw a $2 USB/TTL converter on and do it the same as I did.
I'm trying to reverse the protocol used by an early nineties logic analyzer an its PC software.
The device is connected via RS-232 (propietary wiring) and communicates with a DOS program, successfully running on DOSBOX.
I'm able to control the device with the original software but it would be useful to autimathe the downloading of data from the analyzer using a custom program but to do so I need to know what is going on the serial port.
Ineed to know what mode is the serial port set, while I know for sure the datarate is either 1200 or 9600 bps (configurable on the device) I don't know the flow control (I guess it is RTS/CTS).
I also need to tap into the conversation between the prgram and the device without disturbing their communication.
Reading the serial port with another program (cutecom/minicom) prevents the emulator from receiving the data from the hardware.
So, summing up, what I need to know is:
What configuration is set on /dev/ttyS0 (via IOCTL calls, i think)
What goes on between program and device.
I was thinking in programming a library which acts as a proxy for the standard c library (via LD_PRELOAD) but there must be an easier way to do this.
You can use slsnif (Serial Line SNIFfer).
http://linux.die.net/man/1/slsnif
Here's a link to the sourceforge project so you can download it. I don't believe it comes with any modern distributions but I could be wrong so check your distro's software repository first.
http://sourceforge.net/projects/slsnif/
I use ttyrpld for tty sniffing. I ported it to PPC and run it on 2.6.32. It logs all of the tty traffic on the board to files, one per tty. Works well.
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: