TI-84 Plus CE and TI-73 Explorer: Analog Clock
Introduction
The program ANALOG draws a 12-hour analog clock for any given time, given the hour and minute. The TI-73 program covers the TI-73 Explorer and should be ported to any of the Texas Instruments calculators with monochrome screens with no or little adjustment.
The TI-84 Plus CE adds colors: hour hand is black, minute hand is brown, the markers are orange. Adjust colors to your liking.
Notes:
* The program pauses when the clock is drawn. Pressing [ENTER] restores turns the Axes back on.
* The Pt-On command has the syntax Pt-On(x, y, mark, color*). Mark: Dot (1 or default), Open Square (2), Plus (3). Color applies only to the TI-84 Plus CE or TI-84 Plus C Silver Edition.
* The program sets the calculator to degrees mode.
Math:
Let H be the hour and M be the minute.
Set S = H + M/60, where S is the decimal hour of the time given.
For a circle of 360°, each hour occupies 30° of the clock (360/12). Like wise, each minute occupies 6° of the clock (360/60).
A = 30*S, B= 6*M
Lines are drawn from the origin (0,0) to a point (x,y). If we set x and y to an angle θ, then:
x = r * cos θ, y = r * sin θ, where r is the length of the line.
Angels on a cartesian plane start from the positive x-axis and measured going counter-clockwise. However, on the analog clock requires angels to measured from the top (due north) and rotate clockwise. This will require a vertical flip and adjusting the angle by 90°. The adjusted coordinates are:
x = r * cos (θ-90°), y = -r * sin (θ- 90°), where r is the length of the line.
TI-73 Program: ANALOG
(this includes TI-73 Explorer)
"EWS 2021"
FnOff
PlotsOff
ClrDraw
Degree
Disp "12 HR ANALOG"
Input "HOUR? ",H
Input "MINUTE? ",M
ZStandard
ZSquare
AxesOff
Circle(0,0,8)
For(X,30,360,30)
Pt-On(7*cos(X-90),-7*sin(X-90),2)
End
Line(0,0,5*cos(30H+M-90),-5*sin(30H+M-90))
Line(0,0,7*cos(6M-90),-7*sin(6M-90))
Pause
AxesOn
TI-84 Plus CE Program: ANALOG
"EWS 2021-01-18"
FnOff
PlotsOff
ClrDraw
Degree
Disp "12 HOUR ANALOG CLOCK"
Input "HOUR? ",H
Input "MINUTE? ",M
ZStandard
ZSquare
AxesOff
GridOff
"FACE"
Circle(0,0,8,MEDGRAY)
For(I,30,360,30)
Pt-On(7*cos(I-90),7*sin(I-90),2,ORANGE)
End
"HOUR"
Line(0,0,5*cos(30H+M/2-90),5*sin(30H+M/2-90),1,BLACK)
"MINUTE"
Line(0,0,7*cos(6*M-90),7*sin(6*M-90),1,BROWN)
Pause
AxesOn
Next week, more fun with the TI-73 Explorer.
Eddie
All original content copyright, © 2011-2021. Edward Shore. Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited. This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.
