I need to know how i can make it so that a sprite detects the rate of change and uses it to calculate the “speed”.. I was thinking about using timers and variables.

You are right. If you record the previous x position and previous timer value, you can calculate the speed in x direction of the period since your records as follows:

(((x position) - (last x pos)) / ((timer) - (last timer val)))

If you want the speed, you must compute the distance between the last point (defned by the last x position and the last y position) and the current position (defined with x position and y position). I guess you know the formula to compute the distance between two points. The one with the square root of the square of difference of … ;-)

I forgot to tell you a simpler solution:
just set a hidden dummy sprite to the last position of your main sprite.
Then when you want to compute the speed, you just have to do this:

((distance to [hidden dummy sprite v]) / ((timer) - (last timer val)))

Ok, thanks!

Okay, you seem to be on the right track. Try this script here:

when [space v] key pressed
set [old x v] to (x position)
set [old y v] to (y position)
reset timer
wait until <not <key [space v] pressed?>>
wait until <key [space v] pressed?>
set [new x v] to (x position)
set [new y v] to (y position)
set [time v] to (timer)
set [x distance v] to ((new x) - (old x))
set [y distance v] to ((new y) - (old y))
set [distance v] to ([sqrt v] of ((((x distance)*(x distance)) + ((y distance) * (y distance))))
set [speed v] to ((distance) / (time))
say (join [Speed: ] (join (speed) [units per second])

I was also wondering how to make it so that it wouldnt be randomized with which direction the puck went when hit (im making an air hockey game) , for example, if on left side, then hit at a 45 degree angle to the left, instead of randomly going in an direction or to any direction.

What is the difference between that one and the previous one shown to me by lafoudre

barberl19 wrote:

What is the difference between that one and the previous one shown to me by lafoudre

The other one only calculates in the x direction. Please note that you don't have to use the spacebar start/stop part of the script.
VERY IMPORTANT EDIT: The speed will not be accurate if the sprite bounces off a wall and returns close to its original spot.

Okay, do you know the answer to my last question?

barberl19 wrote:

Okay, do you know the answer to my last question?

Yes, I can help with that too. If your “paddle” is on the left side of the screen:

if <touching [paddle v] ?>
point in direction (((([y position v] of [paddle v]) - ([y position v] of [puck v])) * (1.5)) + (90))
end

If your “paddle” is on the right side of the screen:

if <touching [paddle v] ?>
point in direction (((([y position v] of [paddle v]) - ([y position v] of [puck v])) * (-1.5)) - (90))
end

its in the midde. What do I do if i find myself in that situation? its 3D. Here, ill show you. Look at my untitled project, ill share it as a draft.

maybe you can remix it

barberl19 wrote:

its in the midde. What do I do if i find myself in that situation? its 3D. Here, ill show you. Look at my untitled project, ill share it as a draft.

Hmm. The game looks good by the way, and the speed calculator seemed to work as well. I don't think the above script will work in fixing the puck's direction, so I'll try to rewrite the function ASAP. However, I think I know how to fix the motion of the puck.

when green flag clicked
go to x:(15) y:(0)
set size to (50)%
go to front
go back (1) layers
forever
    if <<touching [Sprite5 v]?> and <([direction v] of [Sprite5 v]) = [90]>> then
        broadcast [message 2 v]
        repeat until <touching [Sprite2 v]?>
            move ((Overall Speed) / (4)) steps
            change size by (-0.1)
        end
        set [Overall Speed v] to [0]
        repeat until <touching [Sprite5 v]?>
            change y by (-5)
            change size by (0.1)
        end
    end
end

ok, thanks!