Creating a flash

I'm currently making a speed camera that records a users speed when passing in front of the camera using llSensor.

The camera is almost ready, it's able to detect the speed and will keep track of the top speeder (and even posts the top speeder using http to a website).

The only thing I would like to add, is that when a user breaks the speed limit, a short flash is made in the direction of the target. I have no idea how this can be done, so any pointers are welcome.

Thanks

Not sure if this is what you're looking for but a particle effect could look like a flash:

default
{
    touch_start(integer num)
    {
        llParticleSystem(
        [PSYS_PART_FLAGS,0 | PSYS_PART_EMISSIVE_MASK | PSYS_PART_INTERP_SCALE_MASK,
        PSYS_SRC_PATTERN, PSYS_SRC_PATTERN_DROP,
        PSYS_PART_START_ALPHA, 1.0,
        PSYS_PART_START_COLOR, <1.0, 1.0, 1.0>,
        PSYS_PART_START_SCALE, <4.0, 4.0, 0>,
        PSYS_PART_END_SCALE, <0.1, 0.1, 0>,
        PSYS_SRC_ACCEL, <0, 0, 0>,
        PSYS_SRC_OMEGA, <0, 0, 0>,
        PSYS_PART_MAX_AGE, 0.2,
        PSYS_SRC_MAX_AGE, 0.15,
        PSYS_SRC_ANGLE_BEGIN, 0.0,
        PSYS_SRC_ANGLE_END, 3.14,
        PSYS_SRC_BURST_PART_COUNT, 1,
        PSYS_SRC_BURST_RADIUS, 1.0,
        PSYS_SRC_BURST_RATE, 0.1,
        PSYS_SRC_BURST_SPEED_MIN, 0.0,
        PSYS_SRC_BURST_SPEED_MAX, 0.0,
        PSYS_SRC_TEXTURE, "" ]
        );
    }
}

Make a 128x256 texture with the top-half solid white and the bottom-half 100% alpha. Create a sphere or cube or something to cover the flash area. Apply the half & half texture. Set the texture scale and offsets so that only the 100% alpha shows (the prim is invisible.)

Now, trigger a llSetTextureAnim() which plays the two texture frames once (no LOOP constant). Maybe something like:

llSetTextureAnim(ANIM_ON, ALL_SIDES, 1, 2, 0, 0, 10.0)