I don\'t feel comfortable harnessing USB device with Delphi and have a next to nothing knowledge of the details of writing device driver (though I\'ve come accross some when le
This was taken from detect if usb device is connected
unit U_Usb;
interface
uses
Windows, Messages, SysUtils, Classes, Forms;
type
PDevBroadcastHdr = ^DEV_BROADCAST_HDR;
DEV_BROADCAST_HDR = packed record
dbch_size: DWORD;
dbch_devicetype: DWORD;
dbch_reserved: DWORD;
end;
PDevBroadcastDeviceInterface = ^DEV_BROADCAST_DEVICEINTERFACE;
DEV_BROADCAST_DEVICEINTERFACE = record
dbcc_size: DWORD;
dbcc_devicetype: DWORD;
dbcc_reserved: DWORD;
dbcc_classguid: TGUID;
dbcc_name: short;
end;
const
GUID_DEVINTERFACE_USB_DEVICE: TGUID = '{A5DCBF10-6530-11D2-901F-00C04FB951ED}';
DBT_DEVICEARRIVAL = $8000; // system detected a new device
DBT_DEVICEREMOVECOMPLETE = $8004; // device is gone
DBT_DEVTYP_DEVICEINTERFACE = $00000005; // device interface class
type
TComponentUSB = class(TComponent)
private
FWindowHandle: HWND;
FOnUSBArrival: TNotifyEvent;
FOnUSBRemove: TNotifyEvent;
procedure WndProc(var Msg: TMessage);
function USBRegister: Boolean;
protected
procedure WMDeviceChange(var Msg: TMessage); dynamic;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
published
property OnUSBArrival: TNotifyEvent read FOnUSBArrival write FOnUSBArrival;
property OnUSBRemove: TNotifyEvent read FOnUSBRemove write FOnUSBRemove;
end;
implementation
constructor TComponentUSB.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FWindowHandle := AllocateHWnd(WndProc);
USBRegister;
end;
destructor TComponentUSB.Destroy;
begin
DeallocateHWnd(FWindowHandle);
inherited Destroy;
end;
procedure TComponentUSB.WndProc(var Msg: TMessage);
begin
if (Msg.Msg = WM_DEVICECHANGE) then
begin
try
WMDeviceChange(Msg);
except
Application.HandleException(Self);
end;
end
else
Msg.Result := DefWindowProc(FWindowHandle, Msg.Msg, Msg.wParam, Msg.lParam);
end;
procedure TComponentUSB.WMDeviceChange(var Msg: TMessage);
var
devType: Integer;
Datos: PDevBroadcastHdr;
begin
if (Msg.wParam = DBT_DEVICEARRIVAL) or (Msg.wParam = DBT_DEVICEREMOVECOMPLETE) then
begin
Datos := PDevBroadcastHdr(Msg.lParam);
devType := Datos^.dbch_devicetype;
if devType = DBT_DEVTYP_DEVICEINTERFACE then
begin // USB Device
if Msg.wParam = DBT_DEVICEARRIVAL then
begin
if Assigned(FOnUSBArrival) then
FOnUSBArrival(Self);
end
else
begin
if Assigned(FOnUSBRemove) then
FOnUSBRemove(Self);
end;
end;
end;
end;
function TComponentUSB.USBRegister: Boolean;
var
dbi: DEV_BROADCAST_DEVICEINTERFACE;
Size: Integer;
r: Pointer;
begin
Result := False;
Size := SizeOf(DEV_BROADCAST_DEVICEINTERFACE);
ZeroMemory(@dbi, Size);
dbi.dbcc_size := Size;
dbi.dbcc_devicetype := DBT_DEVTYP_DEVICEINTERFACE;
dbi.dbcc_reserved := 0;
dbi.dbcc_classguid := GUID_DEVINTERFACE_USB_DEVICE;
dbi.dbcc_name := 0;
r := RegisterDeviceNotification(FWindowHandle, @dbi,
DEVICE_NOTIFY_WINDOW_HANDLE
);
if Assigned(r) then Result := True;
end;
end.
You can use some shell script to do so. when device is connected command lsusb shows this and removes from list after the device gets disconnected. So in your shell script you need to find the difference between old list and current list. Finally you need to run this script as a cron job, which checks in frequent interval.
Regards, Barun Parichha