I need to make a program that would play a sound as I press a push button switch. My idea is to use the USB port, and that if I short 2 wires from it (like for example the data+ and data-), the program would play a sound repeatedly while the 2 wires are shorted. Is my idea possible and simple to do? Can you please help me do it using VB? Thanks a lot for any help.
No, that is not practical. USB ports do not have that feature is far as I know. There are plenty of small, cheap USB microcontroller boards that are up to the task though.
For example, you could get an A-Star 32U4 Micro, program it using the Arduino IDE, and make it send a certain message on the its virtual COM port (which is accessed from the Serial object) when a button is pressed and another message when it is released. Then in Visual Basc, you would use the SerialPort class to connect to the A-Star's COM port and listen for that message.
USB ports are mainly used for transmitter and receiver communications for data transfers. They are not used for open or closed switch detection. In order to use a USB port for switch detection, you can used a serial to USB conversion breakout board with a specialized IC chip designed to detect an open or closed switch and communicate this via the USB protocols to send out a communications data transmission that a switch has just been open or closed. Then you would program an application in any language to listen on that USB port for this specific data transmission for a closed or open thrown switch. You can potentially detect about 4 switches opened or closed simultaneously if you want. And this serial to USB breakout board can easily be purchased online at:
https://www.sparkfun.com/products/199
Related
I get lost trying to figure out how to parse control data in CDC_Control_FS() function. Can you point me any documentation about that?
Background:
I am using stm32f103, trying to implement USB CDC communication with HAL libraries. I need to detect if usb port is opened by PC, it should handle power on scenario as well as cable reconnetion during runtime. After some research I think that checking DTR signal may be the (most elegant) solution. I know there is CDC_Control_FS() function that delivers all line configuration to stm32f103 from PC driver, but unfortunately I don't know data format / how to extract DTR signal, to be able to set some flag for indicating that usb port is currently open or 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.
New to VB.NET here.
I was wondering if there is a way to determine if there is something connected to a specific USB port. For example, I noticed that in the Device Manager under Universal Serial Bus controllers, there are Generic USB Hubs. For one of them, the Location is Port_#0001.Hub_#0003.
For what I am doing, I just want to know if something is connected to that specific USB port. It doesn't matter if it is a flash drive, USB HID, or even a microcontroller.
Thanks
I'm trying to interface the Mindwave (http://store.neurosky.com/products/mindwave-1) with my Altys board, through the USB UART port. The dongle I'm trying to connect is basically a wireless reciever that outputs serial data stream on the USB connection. I'm trying to read in this serial stream on the FPGA.
The problem I'm seeing is that when I try to Chipscope the UartRx pin (A16), I see no activity on it even though the dongle is supposed to send 0xAA in standby mode.
Since the FPGA does not power the dongle, I have it connected to an external power USB hub and then connect the hub to the FPGA. However I don't see any activity.
Do I need to convert the signals to another level, or invert them? I thought the EXAR chip takes care of it.
Did you try swapping RX and TX?
Did you have acces to a scope? To check you can repeatly send 'U's (0x55) and look with a scope to see which line is RX and which is TX. You can also check the speed of the interface with this method.