Do you know how to emulate holding down a keystroke for any period of time, then releasing it later?

I'm trying to emulate pushing the keyboard V key down while using BASS library to automate Voice Activation push to talk. I've got the BASS library working, just can't get the keyboard to simulate holding down a Key for any length of time!

Edit: I am trying to get another application ('TeamSpeak 3') to recognize my Key Press & hold as a hardware based Key Press & Hold rather than a software based Key Press & Hold. To help simulate a Push to Talk via my application. I will openly have the source code for anyone that wants it, but I will not be publishing my application for any reason. It's for my personal use and It's out of curiosity if it would work? I understand that any kind of abuse of this kind of app I take as my own personal responsibility.

Edit2: I have done extensive research. I figure I'm going to have to either use my old Android handheld or a Raspberry Pi. I have a Raspberry Pi Zero, so I am going to see if I can create it as a hardware keyboard. I'll write a program in Delphi to interface it (I have Delphi 10.4.1 Enterprise and hope it will work with Raspberry Pi's linux version.) I have a vmware Debian and Ubuntu os on my computer that I could pre-compile it with? Anyhow the article is here: https://randomnerdtutorials.com/raspberry-pi-zero-usb-keyboard-hid/

I'm going to go ahead an allow the answer below, because it basically does what my previous request says. To go further than my request requires a lot of work. I'll give an update if I can get it working properly.

(Delphi 10.4.1 / Target Windows 32-bit)

Here's my current source code:

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.MPlayer, System.UITypes, BASS,
  Vcl.ExtCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Memo1: TMemo;
    Timer1: TTimer;
    ComboBox1: TComboBox;
    Timer2: TTimer;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure ComboBox1Change(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure Timer2Timer(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    function RecordingCallback(h:HRECORD; b:Pointer; l,u: DWord): boolean; stdcall;
  end;

var
  Form1: TForm1;
  rchan:   HRECORD; // recording channel
  level2: dword;
  LoudEnough: boolean = FALSE;
  threshold: DWORD = 500; // trigger level
  MicON_Timer, Counter1: Cardinal;
  MicON_Bool : Boolean;

implementation

{$R *.dfm}

(* This function called while recording audio *)
function TForm1.RecordingCallback(h:HRECORD; b:Pointer; l,u: DWord): boolean; stdcall;
 //var level:dword;
 begin
  level2:=BASS_ChannelGetLevel(h);
  LoudEnough := (LoWord(level2) >= threshold) or (HiWord(level2) >= threshold);
  //Memo1.Lines.add('Loword ' + IntToStr(LoWord(level))+' - HiWord '+IntToStr(HiWord(level)));
  Result := True;
 end;

// START BUTTON
procedure TForm1.Button1Click(Sender: TObject);
begin
  {
  if BASS_RecordSetDevice(0) = false then
  begin
    memo1.Lines.Add('BASS_RecordSetDevice ERROR = '+ BASS_ErrorGetCode().ToString);
  end;}

  Counter1 := 0;
  MicON_Timer := 0;

  Timer1.Enabled := true;
  ComboBox1Change(Self);
  rchan := BASS_RecordStart(44100, 1, 0, @TForm1.RecordingCallback, nil);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  Timer1.Enabled := false;
  rchan := BASS_RecordStart(44100, 1, BASS_RECORD_PAUSE, @TForm1.RecordingCallback, nil);
    //BASS_Free();
end;

procedure TForm1.ComboBox1Change(Sender: TObject);
var
    i: Integer;
  r: Boolean;
begin
    // enable the selected input
    r := True;
    i := 0;
    // first disable all inputs, then...
    while r do
    begin
        r := BASS_RecordSetInput(i, BASS_INPUT_OFF, -1);
        Inc(i);
    end;
    // ...enable the selected.
    BASS_RecordSetInput(ComboBox1.ItemIndex, BASS_INPUT_ON, -1);
    //UpdateInputInfo;  // update info
end;

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  BASS_RecordFree;
  BASS_Free();
end;

procedure TForm1.FormCreate(Sender: TObject);
var
  i: Integer;
  dName: PAnsiChar;
  level: Single;
  flags: dWord;
  deviceInfo: BASS_DEVICEINFO;
  info: BASS_INFO;
begin
    // check the correct BASS was loaded
    if (HIWORD(BASS_GetVersion) <> BASSVERSION) then
    begin
        MessageBox(0,'An incorrect version of BASS.DLL was loaded', nil,MB_ICONERROR);
        Halt;
    end;
    if (not BASS_RecordInit(-1)) or (not BASS_Init(-1, 44100, 0, Handle, nil)) then
    begin
        BASS_RecordFree;
        BASS_Free();
        MessageDlg('Cannot start default recording device!', mtError, [mbOk], 0);
        Halt;
    end;
    i := 0;
//  dName := BASS_RecordGetInputName(i);
  //dName := (BASS_RecordGetDeviceInfo(i,deviceInfo));
    while (BASS_RecordGetDeviceInfo(i,deviceInfo)) do
    begin
    //BASS_GetInfo(info);
        ComboBox1.Items.Add(String(deviceInfo.name));
        // is this one currently "on"?
    //flags := BASS_RecordGetInput(i, level);
    //if (flags and BASS_INPUT_TYPE_MASK) = BASS_INPUT_TYPE_MIC then
        if (BASS_RecordGetInput(i, level) and BASS_INPUT_OFF) = 0 then
            ComboBox1.ItemIndex := i;
        Inc(i);
        //dName := BASS_RecordGetInputName(i);
    end;
    ComboBox1Change(Self);  // display info
end;


procedure TForm1.Timer1Timer(Sender: TObject);
var
  eu: array [0..1] of TInput;
  //S: String;
begin
  //S:='v';
  level2:=BASS_ChannelGetLevel(rchan);
  inc(Counter1);
  LoudEnough := (LoWord(level2) >= threshold) or (HiWord(level2) >= threshold);

  if (LoudEnough = true) then
  begin
    inc(MicON_Timer);

    if (MicON_Bool = false) then
    begin
      MicON_Bool := true;

      //keybd_event(ord('v'), MapVirtualKey(ord('v'), 0), KEYEVENTF_KEYUP, 0);
      //keybd_event(ord('v'), MapVirtualKey(ord('v'), 0), 0, 0);

      ZeroMemory(@eu,sizeof(eu));
      eu[0].Itype := INPUT_KEYBOARD;
      eu[0].ki.dwFlags := KEYEVENTF_UNICODE;
      eu[0].ki.wVk := 0;
      eu[0].ki.wScan   := ord('v');
      eu[0].ki.Time := 0;
      SendInput(1,eu[0],sizeof(TInput));

      Memo1.Lines.add('Push to Talk ON');

      Timer2.Enabled := true;
    end;
  end;

  //if LoudEnough then Memo1.Lines.add('Push to Talk ON')
    //else Memo1.Lines.add('Push to Talk OFF');
  //Memo1.Lines.add('Loword ' + LoWord(level2).ToString +' - HiWord '+ HiWord(level2).ToString + ' - AVG: ' + MicON_Timer.ToString);
end;

procedure TForm1.Timer2Timer(Sender: TObject);
var
  eu: array [0..1] of TInput;
begin
  dec(MicON_Timer);
  if MicON_Timer <= 0 then
  begin
    Memo1.Lines.add('Push to Talk OFF');

    //keybd_event(ord('v'), MapVirtualKey(ord('v'), 0), KEYEVENTF_KEYUP, 0);
    ZeroMemory(@eu,sizeof(eu));
    eu[0].Itype := INPUT_KEYBOARD;
    eu[0].ki.dwFlags := KEYEVENTF_UNICODE or KEYEVENTF_KEYUP;
    eu[0].ki.wVk := 0;
    eu[0].ki.wScan   := ord('v');
    eu[0].ki.Time := 0;
    SendInput(1,eu[0],sizeof(TInput));

    MicON_Bool := false;
    Counter1 := 0;
    MicON_Timer := 0;

    Timer2.Enabled := false;
  end;
end;

end.