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With a Photron Fastcam SA5 highspeed camera it is easily possible to mark events by applying an electrical TTL signal on the general input connector. This enables you to jump to certain positions in the video by pressing a single button.

On the other hand it is completely impossible to mark frames in the Photron software.

But you can just write into the CIH file. You have to give the total number of events (maximum of 10) and the Frame numer where the event takes place.

In this example you will get three event markers at Frame 214, 426 and 638.

Number Of Event Marker : 3
Event Frame1 : 214
Event Frame2 : 426
Event Frame3 : 638

When you wan't to reset your Arduino, you can use the watchdog timer to do this. Just by enableing the watch dog

wdt_enable(WDTO_1S);
while(1){}

you restart your system. After restart, you have to disable the watchdog timer to avoid a unfinite loop of restarts. So first command in the setup()-function should be something like

wdt_disable();

For me, this works fine as long as my board is powered over USB (5V).

With an external power supply of 12V on the other hand, my device could not do a proper restart process. The watchdog timer was to fast after boot up, so I got to the cycle of reboots. I think the watchdog timer depends on the Vin voltage and gets faster with increasing Vin. In this case it was too fast. Symbolic constants for the watchdog timeout. Since the watchdog timer is based on a free-running RC oscillator, the times are approximate only and apply to a supply voltage of 5 V. At lower supply voltages, the times will increase. For older devices, the times will be as large as three times when operating at Vcc = 3 V, while the newer devices (e. g. ATmega128, ATmega8) only experience a negligible change.

The solution for me was to use a power supply with only 7V , so Vin is just a little over 6V and the behaviour of the arduino board is like with USB power.

To create to positions of a hexagonal lattice is simple. This algorithm can be used to connect these hexagonal lattice points and create a honey comb pattern.

#include 
#include 
#include 

double vx[100][100];
double vy[100][100];




double posX(int x,int y)
{
  return x-(y%2)*0.5+vx[x][y]*0.7;
}

double posY(int x,int y)
{
  return y*0.866+vy[x][y]*0.7;
}

int setKnod(int x,int y, double a)
{  printf("\n",posX(x,y)*a,posY(x,y)*a);
}


int setCon(int x1,int y1, int x2, int y2,double a)
{
 printf (" \n",x2,y2);
}

main()
{
int x,y;

double a= 20;
double da= a*0.866;

int Ny=10;
int Nx=10;

srand(time(NULL));

for (y=0;y<=Ny;y=y+1)
   {
   for (x=0;x<=Nx;x=x+1)
     {
	 if (((x%3==0) && (y%2==0)) || ((x%3==2) && (y%2==1))  )
       {
	      //printf ("%.3f\t%.3f\n",x-(y%2)*a/2,y*da);
	      
		  vx[x][y]= (float)rand()/RAND_MAX;
		  vy[x][y]= (float)rand()/RAND_MAX;
		  setKnod(x,y,a);

		  vx[x+1][y]= (float)rand()/RAND_MAX;
		  vy[x+1][y]= (float)rand()/RAND_MAX;
	      setKnod(x+1,y,a);
		  printf ("\n");
	   }


	 }
   }

printf("\n");

for (y=0;y<=Ny;y=y+1)
   {
   for (x=0;x<=Nx;x=x+1)
     {
	 if (((x%3==0) && (y%2==0)) || ((x%3==2) && (y%2==1))  )
       {
		  setCon(x,y,x+1,y,a);
		  
	      if (y0)
		    {
   	        setCon(x+1,y,x+1+((y+1)%2),y-1,a);
		    }
		  printf ("\n");
	   }


	 }
   }

printf("\n");
}