Showing posts with label clock. Show all posts
Showing posts with label clock. Show all posts

Saturday, January 20, 2024

Retro Review: Panasonic CompuVoice JF-721U

Retro Review:  Panasonic CompuVoice JF-721U



My partner, Chris, gave me this calculator as a Christmas present.  Thank you and love you, Chris!









Quick Facts


Model:  JF-721U

Company:  Panasonic

Timeline:  early to mid 1980s

Type:   Four Function Calculator, Stopwatch, Timer, Clock, with Voice

Number of Digits:  8

Power:  3 AA batteries



An All-In One Calculator



This is like a dream machine:  a calculator, a clock, stopwatch, timer, and it talks, and it came with a beautiful brown leather power that shows the clock and a button labeled [ TIME ], when pressed the calculator reads the time.   [ TIME ] is located on the upper left hand corner of the calculator next to its speaker.  


Chris definitely did well!


The voice is a male machine voice, loud and clear. 



The Three Modes:  LOCK, COMP-TIME-STOP WATCH, and SET



The switch on the JF-721U selects the calculator's three modes:  LOCK, COMP-TIME-STOP WATCH, and SET.   Let's go through these modes one by one.   



LOCK Mode


LOCK mode is basically the calculator's sleep mode.  The display shows the clock and the only key that operates is the [ TIME ] button.  



COMP-TIME-STOP WATCH Mode


On this mode, we can run the calculator, timer, and the stopwatch.   


Timer:  The timer can be set in hours (h) and minutes (m) only.  To set the timer, press the [ SET ] button, enter the time desired in hh-mm format, and press [ S/S ].   The [ S/S ] acts as the start/stop button.


Stopwatch:  The stopwatch is actived by pressing the [ SET ] and [ S/S ] keys in sequence to start the stopwatch.  The stop the stopwatch again, press the [ S/S ] key and record the time.   If the voice is turned on, the final time will be read.   We can start and stop the stopwach as many times as we want.  


To cancel the stopwatch without seeing the result, press the clear [ C ] button.


Calculator:  The JE-721U is a four-function calculator.   The calculator is activated by the clear [ C ] button.   There are three standard memory keys:  memory plus [ M+ ],  memory minus [ M- ], and memory recall-clear [ MRC ].  The number in the memory register is retained as long as there is battery power.


One curious thing with the percent key, [ % ], is that the key only works with multiplication and division problems.  


To add a percent: 

Enter the number, press [ × ], enter the percent, press [ % ], press [ + ]


To subtract a percent: 

Enter the number, press [ × ], enter the percent, press [ % ], press [ - ]


The calculator's change sign key is labeled [ (-) ]. 


In this mode, the calculator's voice is toggled on and off by the [ VOICE ] key.


The hour [ HOUR ] key is also available.  If the hour key is on, then the calculator will announce the hour.



SET Mode


We can set the clock and the alarm in SET mode.   In this mode we can set the clock and an alarm.


To set the clock:  press [ SET ], enter the hour and minute, and then the [ TM ] key.  


To set the alarm:  press [ SET ], enter the hour and minute, and then the [ ALM ] key. 


In this mode, the decimal key, [ . ], switches between AM/PM.   


If this calculator can handle military time (00:00 to 23:59), I don't know how to set it.  Also, the calculator is a clock only, so for daylight savings time, the time must be manually set. 



Final Thoughts


I like this calculator.  The voice is loud and clear and the time functions are really nice additions.   I imagined the CompuVoice calculators set on the desks of professionals and were companions of travelers back in the 1980s.     




Eddie


All original content copyright, © 2011-2024.  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. 


Sunday, February 28, 2021

TI-84 Plus CE and TI-73 Explorer: Analog Clock

 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. 


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