rocket launcher

hi i am kind of new to all this but i have good tec mind what i want to do is make a rocket launcher with an lcd to count down the time when i press a switch and when it gets to 0 it turns on a relay for about 5 seconds and then stops also some sound would be nice like beeping

any help would be great

That all sounds very straightforward. Some suggestions:

LCD display: text-mode displays are the easiest to drive. 16 columns by 2 lines is a popular size. If you want larger digits, use a graphic LCD (e.g. 128 x 64 pixels) instead. Or, as you only need to display 1 or 2 digits, you could use some large 7-segment LED displays instead.

Relay: use a transistor such as BC337 to drive it, and don't forget the flyback diode.

Sound: piezo sounders are inexpensive and very easy to drive, but not very loud. If you find you need a louder sound, you can replace the piezo sensor with a couple of transistors driving a small loudspeaker.

Safety: always assume that the Arduino might malfunction or your circuit or software might not be right, leading to premature launch. So make sure the power to the rocket ignition circuit is physically disconnected whenever there is anyone near the rocket.

You might also want to use the Arduino to check that there is continuity in the ignition circuit.

thanks for getting back to me i have got all the parts i have also tried to write the code but not having much luck in the count down for another project but i want to add the keypad so the correct code would have to be entered to start the count down any help with how i could add this in the code would make me day thanks

how i could add this in the code

You haven't shown us the code, so it is all but impossible to show you where to add anything to it.

sorry yes that would help well here it is

#include <LiquidCrystal.h>
 // initialize the library with the numbers of the interface pins
 LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
 int runTimer = 1; // true condition for timer
 int serialData = 0; // false condition for serial communication
 int speakerPin = 8;
 int data = 0; // default condition
 void setup() {
   pinMode(speakerPin, OUTPUT);
   // set up the LCD's number of rows and columns: 
   lcd.begin(16, 2);

 void loop() {
   // To execute timer only once
   if(runTimer == 1){ 

   // Print a message to the LCD.
   lcd.print("Timer: ");
   //Start timer
   runTimer = 0;
   // Sound Buzzer
   for(int duration = 0; duration < 100; duration ++){
     digitalWrite(speakerPin, HIGH);
     digitalWrite(speakerPin, LOW);
   while (1);
 void timer(){
   // For loop to run the COUNT-DOWN in Seconds
     for(int timer = 10; timer > 0; --timer){
     // Set the Curosr to the space after the display "TIMER: "
     if(timer >= 10)
     // Display the COUNT-DOWN Seconds
     // Bring the Cursor to the initial position 
     lcd.print("   !Take Off!");

You need to put your code inside [ code ] [ /code ] tags to stop the forum software mangling it. You can do that by editing your post, selecting all the code and clicking the '#' button in the edit window.

thanks for that ill know that now for the future :smiley: