I have an infrared thermometer which operates on a virtual serial port over USB, which I am trying to use on a Linux intel and next on a raspberry Pi. The system did not enumerate a /dev/ttyUSB device.
I found a piece of a solution here :
Cygnal Integrated Products serial port on Linux
I reprogrammed the product_ID and can now see it as /dev/ttyUSB0.
But trying to talk to the thermometer with minicom doesn't work.
minicom keeps saying "disconnected" despite the "9600 8N1" indication.
I must say, I had many attempt to work with this kind of communication over USB/serial adapter trying using many different terminal emulator like screen or minicom but without any success at all !
I'm not even sure about the right way to send request and receive data.
Here is the documentation I'm using trying to talk to the thermometer :
http://www.optris.com/interfaces?file=tl_files/downloads/Manuals/addendums-de-en/ct-ctlaser-commands.pdf
Edit :
I'm now trying to use PySerial Python library in a Python script with an Arduino as a target (to act as my thermometer, the arduino runs a simple code that takes the data received and send them back to my Python console.) But still, there is so many confusion possible between ASCII, Hexa, binary, that I'm not capable of debugging anything as I don't know where the transformation between different format takes place !
The communication is working as I can get some data forth and back from my Python console through the Arduino. But I can't get sending hexadecimal data and getting any response back in hexadecimal format. + You say "Your latest question puts you in the off-topic category. ", what do you mean ? Sorry of being so confused.
Related
I was able to make a working HID USB stack on my "StartUSB for PIC" board for the 18F2550 microcontroller. I based it on one of the MLA libraries, which was made for the 18F45K50 (MLA 2018_11_26, hid_custom, picdem_fs_usb_k50.x), but I converted it to work with the 18F2550 (there might have been easier ways, but only learned to work with PIC about 1 month ago). On the host side, I'm using LibUsbDotNet (also here, there might be easier ways - the documentation on this library really sucks) on a Windows 10 machine.
I'm using the HID class, full speed, and all seems to work. Although, I get some random errors on the host PC (see below), but doing one close/re-open cycle on the host side when getting the error is kind of solving it. Dirty, but it works. So I kind of ignore this now.
Win32Error:Win32Error:GetOverlappedResult Ep 0x01
995:The I/O operation has been aborted because of either a thread exit or an application request.
I'm not an expert on USB (yet). But all examples I'm seeing are based on 1) you send first a command to the device and 2) then you retrieve the answer from the device. I did some performance tests, and see that this indeed shows that I can do about 500 cycles/second. I think that is correct, because each cycle, sending command and retrieving answer, each takes 1 msec.
But do I really need to send a command? Can't I just keep reading endlessly, and when the device has somthing to say, it does send the data in an IN transaction, and when not it ignores which creates a timeout on the host side. That would mean that I can poll at 1000 cycles/second? Unfortunately, I have tried it by changing my implementation on the PIC, but I get very weird results. I think I have issues with suspend mode. That brings me to another question - how can I make the device get out of suspend mode (means that not the host, but the device should be triggering this event). I have searched the MLA library for command such as "wakeup", "resume", ... but couldn't find anything.
So, to summarize, 2 questions:
Conceptual: Can I send data from device to host without being requested for it by a command from the host?
For PIC experts: How can I have a device trigger for a wakeup from suspend mode?
And indeed, the answer is Yes on the first question.
In the meantime, I found another link on the web that contains a Visual Studio C# implementation of a USB library including all the source files.
If you're interested, this is the link
This C# host implementation works as a charm. Without sending a command to the device, I get notified immediately if a button is pressed. Great!
It also proofs that my earlier device implementation based on the original MicroChip MLA, is 100% correct. I stress tested the implementation by sending a "toggle LED command" as fast as I could, and I reach 1000 commands/second. Again great!
I think that LibUsbDotNet isn't that perfect after all. As I wrote above, I get rather unstable communication (Win32Error). But with this implementation, I don't get a single error, even after running for half an hour # 1000 commands/second.
So for me, case closed.
I'm playing around with an old Trackball I purchased from Sparkfun. My trackball powers on, but it doesn't actually work. All the lights flash, and it indicates that I've left and right clicked, but the mouse on my screen does nothing.
I want to monitor the input values of the trackball across a USB port so I can track down the problem. I've looked for code I can run on Netbeans, but came up empty handed.
Please advise
You didn't specified what OS are you using. You need dedicated driver for this device. In case of Linux you would need to write your own driver for the kernel. But first you need to have specification of protocol which this device is using over usb and also usb protocol itself. It is quite sophisticated task to do...
In case of Windows there are some programs for dumping transmission between usb host (PC) and device (trackball), but at the moment I can't give you any name of such program. In case of Linux you can dump the transmission using tcpdump or wireshark commands.
I'm running some code on Arduino, I have website with a slider which uses a cgi script to pass values to Python. Then the python script uses pySerial to send the values to Arduino which controls a motor.
The plan was to be able to control the motor speed using the slider on the website.
However I seem to be coming up against a problem of the Arduino resetting whenever I change a value on the website, causing the motor to stop. Is there any way around this? My python code is below.
#!/usr/bin/env python
import cgi
form=cgi.FieldStorage()
import json
ser = serial.Serial('dev/ttyACM0', 9600)
#I think there should be a sleep here for 1.5 seconds
ser.write("%s\n" % (form["value"]))
ser.close()
print "Content-type: application/json"
print
print(json.JSONEncoder().encode({"status":"ok"}))
So, say I have the motor running at 50% speed, then change a value on the website, it runs this script which executes the serial.Serial('dev/ttyACM0', 9600) command. That opens the port which resets the arduino, stopping the motor before passing the new command.
Is there any way to pass ser.write("%s\n" % (form["value"])) to the arduino without freshly opening the port? Such as leaving the port open between python sessions?
If not, is there any other way around this problem?
I believe the reset is due to a hardware design of the specific Arduino device you are using. I suggest using an Arduino Micro or Leonardo board instead. They use a virtual serial port and should not restart your sketch each time a serial port is opened. This is from the Arduino site:
No reset when you open the serial port.
Unlike the Arduino Uno, the Leonardo and Micro won't restart your
sketch when you open a serial port on the computer. That means you
won't see serial data that's already been sent to the computer by the
board, including, for example, most data sent in the setup() function.
Serial re-enumeration on reset.
Since the boards do not have a dedicated chip to handle serial
communication, it means that the serial port is virtual -- it's a
software routine, both on your operating system, and on the board
itself. Just as your computer creates an instance of the serial port
driver when you plug in any Arduino, the Leonardo/Micro creates a
serial instance whenever it runs its bootloader. The board is an
instance of USB's Connected Device Class (CDC) driver. This means that
every time you reset the board, the USB serial connection will be
broken and re-established. The board will disappear from the list of
serial ports, and the list will re-enumerate. Any program that has an
open serial connection to the Leonardo will lose its connection. This
is in contrast to the Arduino Uno, with which you can reset the main
processor (the ATmega328P) without closing the USB connection (which
is maintained by the secondary ATmega8U2 or ATmega16U2 processor).
This difference has implications for driver installation, uploading,
and communication...
I you might be able to use the setDTR(False), but I have tested this yet. A while back they fixed the bug that were initially associated with setDTR. What operating system are you use this on?
ser = serial.Serial('dev/ttyACM0', 9600)
ser.timeout = 1
ser.setDTR(False)
Let us know if this does not work.
Over the past two days, I am doing some reading on how to get data over USB from an external device which has no device driver installed. I have to read data from a WT500 Yokogawa Power Meter (basically I want to read just one of the parameter that the meter shows, just the power values) over USB. I am aware that a device driver for WT500 is available, but it has some dependencies and I do not want to install a software or change anything majorly in our node to cater to that.
I have found that libusb could be used to perform what I would want, and I have a C program that sniffs the USB device and returns some information. I have looked into usb-robot as well, which also uses libusb. The server node that I am probing has OpenSUSE Linux kernel 2.6.30. I have usbfs mounted.
Question:
I am expecting that using libusb, I would be able to get data dumps from the power meter whenever I request, via usb device. Can I request the meter something like - send 25k of data, and then upon parsing it, I get the parameter value that I am looking for? Considering that I have zero knowledge about the device, can I get some meaningful values out of it? An example code would help.
--
There are some standard messages like ?IDN with which a USBTMC device could be queried. However, specific queries need to be sent to a meter (the syntax should be there in the technical doc/manual/communication interface) if one needs to get whatever is showing up on screen.
I guess there are no easier ways of doing what I want - like just reading a file using something like fread ??
--
Yes, almost. If USBTMC module is installed (the default one in our kernel did not work, detailed explanation of installing and querying a device is here - http://code.google.com/p/scte/wiki/USBTMC), then one just needs to send some queries and read the response via cat or something from the specific files under /dev.
From the meter technical document, I see that the driver communication interface that is described is Windows specific, so I reckon I might need to do some reverse engineering.
--
Yes, but only a tiny bit or may be not at all.
Thank you.
EDIT: After a bit of googling I think I have the answers, I have added them next to the questions I asked.
im trying to read the current position of GPS Device...using N95 from Nokia.
I read tht i will need my device to return the NMEA lines to the serialport and then i will parse/split it to get things I want but all along I dont know what to write to the serialport to make device return the NMEA ?
Like There are other commands of AT for messaging etc...Is there any specific command to send to serialport to get NMEA ???
I found this site site which seems to guide you through everything you need to do.
I am not sure how it works in the N95, but in my HTC phone you cannot send commands to the GPS device to have it behave in a certain manner. Once I am connected to the serial port that the GPS device uses I can read a stream of data coming from it, which happens to be NMEA data. There is no way that I have found to send commands to the device to tell it how to behave.
I haven't used that specific GPS device before, but for mine, I just have to open the port and I start receiving the NMEA data immediately.
I have an N82, and as far as I know it doesn't speak NMEA directly. I use a script from this page - specifically one the titled "# Turn your S60 phone with an internal GPS (eg your N95) into a Bluetooth GPS" - to get NMEA strings.
Ahh oki so I need to run some script.Oki I think i should buy a specific GPS Device for it.
Which device will do my job in cheapest manner ?
I've never worked specifically with the N95, but most GPS devices will just start spitting out NMEA as soon as they're powered up, regardless of whether or not they have a lock. I don't know how the N95 is designed, but I'll bet it probably wasn't designed to give you access to the raw NMEA data from the GPS. You'll probably need some pretty fancy trickery to get it to do that.
If you don't need to use the N95, you might find it easier to just get a GPS module and use that instead. I've always purchased mine from SparkFun. They have some good evaluation boards boards and tutorials to help you get started.
A great way of doing this in Java ME is to use JSR 179: the Location API. Your app needs to create an implementation of LocationListener, then set it on the default LocationProvider. When your listener's locationUpdated method gets called, call:
location.getExtraInfo("application/X-jsr179-location-nmea");
This will provide access to the NMEA sentences.
You can send this over a serial port by using the Java ME commports mechanism (use:
System.getProperty("microedition.commports");
as described here).
Hope this helps,
funkybro