NTNUJAVA Virtual Physics Laboratory
Enjoy the fun of physics with simulations!
Backup site http://enjoy.phy.ntnu.edu.tw/ntnujava/

This applet is created with EJS 4. You can find out how to find information about world time with java.
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thanks. that was very useful

i have discussion of collection of clock telling time digital interactive over here http://66.7.205.91/~lookangc/index.php?topic=333.msg752#msg752

some of the people here might be interested to look at them to get good ideas/features to modify the EJS open source version by Prof. Fu-Kwun Hwang

EJS could be a future platform for virtual labs/simulations for collaborations under creative commons licenses.

strange when i download the source xml and recompile it in Ejs 4.3.31 or 4.27.

on drag of the sliders, the clock goes all over the clock unlike the version above.

any idea what is wrong?  ;D

Dear Prof Hwang,

I tried to remix the clock.

but i could not replicate the drag on of the minute and hour hand in your simulation model to have a second hand drag-able with the perfect transition of the second hand from 1 to 59. I have created a second hand drag-gable ( http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=2276.0 ) but with bugs i cannot eliminated thus, i seek your help :)

i do not understand the codes inside the minute hand and the hour hand.
for example: in the minute hand
ctam=Math.atan2(mx,my);// ctaangle of minute hand
if(ctam<0)ctam+=pi2;
vm=(int)(ctam/pi2*T);
if(Math.abs(vm-vms)>40.){// why 40? arbitrary
 if(vms<30){ // why 30? i thought it should be 60 minutes?
   vh=vh-1; // original was vh+=1; i think
   testm=-1; // my codes to debug which lines is executed
   }
 else if(vms>30){  // why 30? i thought it should be 60 minutes?
   vh=vh+1;
   testm=1; // my codes to debug which lines is executed
   }
 if(vh==12 || vh==0){ // this should not impact the drag right? i have not implemented it
  if(hadd>0)hadd=0;
  else hadd=12;
  if(hours24)vh2=vh+hadd;
  }
}
set();
//cta=(vs+vm*60+vh*3600*5)*pi2/T;

where
public void set () {
vs=vs+vm*60+vh*3600*5;
cta=vs*pi2/T;
}


could i request 1 thing?  ;D

an add-on to your simulation to have the second hand drag-gable without the bugs i have created in my remixed sim found here http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=2276.0

please add some useful comments lines // so i can follow the program logic more closely to your thoughts.
Thanks!!

The angle for minute hand is vm, vms is previous angle 


ctam=Math.atan2(mx,my);
vm=(int)(ctam/pi2*T);

The angle is zero degree when value for minute is 15.
The angle for minute=0 is 30 degree.

 if(vms<30)vh--;// counterclockwise rotating so hour value decrease by 1: vh-- is the same as vh=vh-1;
 else if(vms>30)vh++;// clockwise rotating  so hour value increase by 1: vh++ is the same as vh=vh+1;

if(Math.abs(vm-vms)>40.){// this is related to how fast user drag it, the value was found by try and error (I think)

dear prof!

i discovered a bug that i cannot solve alone.
maybe you can see if it can be solve?
attached is the animated gif
the bug occurs when the hand hour is drag pass the 12 mark, to the left can produced the bug ( the hour hand jumps to 11 instead of staying at 12)
(http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=990.0;attach=4392;image)
thanks!

i also noticed if the user drag the hour hand pass the 12 mark left and right a few times
the time appears to have another bug as the time change from 11.59 AM to 12.01 PM and turn back, it should be 11.59AM but the bug remains it at 11.59 PM.
do you notice that too :)

for ur info
i look forward to any bug fixes  :D

dear prof hwang,

i found a bug when time is say time is HR : MM : SS

when MM =59 and SS = 59
clock is suppose to be HR = HR +1 when SS becomes 60 in the next time step dt.

but instead the HR jumps back to HR causing the clock to be trap in a infinite loop of HR.


attached is my ejss source and model files

can you fix the bug on your ejs (so i can examine your solution) or my ejss(so i can continue building it)?

thanks!

Please check out the following

i have created this, thank you for being a great mentor Prof Hwang!

http://iwant2study.org/ospsg/index.php/interactive-resources/mathematics/measurement-and-geometry/measurement/2-time/425-clock24wee01

<iframe width="100%" height="750" src="http://iwant2study.org/lookangejss/01_measurement/ejss_model_clockgeogebrawee/clockgeogebrawee_Simulation.xhtml" frameborder="0">