Retro Review: Texas Instruments TI-65

Retro Review:   Texas Instruments TI-65

Quick Facts:

Model:  TI-65 Technical Analyst 

Company:  Texas Instruments

Years:  1986-1989

Type:  Scientific, Programming

Batteries: 2 x LR44

Operating Mode:  AOS

Memory Registers:  up to 16 (0-F)

Programming Steps:  up to 100

Comes in case

Stopwatch and Timer Included

Features

The TI-65 is a late entry of the Texas Instruments and has the following features:

*  Trigonometry, Logarithms, Powers

*  Absolute value, integral and fraction part

*   DMS and HMS conversions  (degrees and hours, respectively, 360° for degrees, 24 hours)

*  Eight scientific constants

*  Eight conversions  (→ (US to SI),  INV for ← (SI to US), except Joules/calories which the order is reversed)

*  Base conversions to hexadecimal and octal only (unfortunately not binary nor any Boolean algebra)

*  Statistics

*  Linear Regression

*  Storage Arithmetic 

*  Numeric Integration

*  Programming

Scientific Constants (the values stored in the TI-65):

c:  Speed of light = 299792458 m/s

g:  Earth's gravity = 9.80665 m/s^2

me: Mass of an electron = 9.109534 * 10^-31 kg

e:  Charge of an electron = 1.6021892 * 10^-19 C

h:  Plank's Constant = 6.626176 * 10^-34 J s

k:  Boltzmann's Constant = 1.308662 * 10^-23 J/K

Na:  Avogadro's Constant = 6.022045 * 10^23 molecules/mole

R:  Gas Constant = 8.31441 J/(mole * K)

The SI units are printed with the constants on the TI-65, which I like.  

Conversions:

inches - centimeters

ounces - gallons

gallons - liters

degrees Fahrenheit - degrees Celsius

pounds per inch - Pascals

horsepower - kilowatts

Joules - calories

pounds (* foot) - Newtons

Programming, Integration, and Memory

The TI-65 has 100 programming steps that is shared with the memory register.   A register is worth seven programming steps, and the amount of memory registers available decrease as you type in steps.   Most programming steps are fully merged, hence 2nd, 3rd, and INV (indicated by a negative sign in the key code) with its key count as one step.  However, storage arithmetic takes two steps.

Maximum Number of Memory Registers vs. Maximum Amount of Steps

100 steps:  1 register (R0)

98 steps:  2 registers (R0, R1)

91 steps:  3 registers (R0, R1, R2)

84 steps:  4 registers (R0 to R3)

77 steps:  5 registers (R0 to R4)

In learn mode, the number of steps and the maximum number of registers are on display, along with the programming step.  

Memory registers can be protected by the [ 2nd ] (PUM) # sequence.  

A full set of programming commands are here:

DSZ:  decrement R# and skip if zero

INV DSZ:  decrement R# and skip if not zero

x<m:  test x < R#

INV x<m:  test x ≥ R#

x=m:  test x = R#

INV x=m:  test x ≠ R#

x>m:  test x > R#

INV x>m:  test x ≤ R#

LBL and GTO:  label (0-9, A-F, F1, F2)

F1 and F2:  user keys and labels

PAUSE:  pauses execution

SBR:  subroutine

INV SBR:  return

LIST:  display steps stored in memory

Integration:  Integration requires R0, R1, and R2 to be protected by PUM 2.  In the program, use R1 for x (you are given x in the register to start), end the function with [ = ] [ R/S ].    Calculation:  lower [ STO ] 1, upper [ STO ] 2, [ 2nd ] ( ∫dx) n [ R/S ]

Statistics:  Clear all protection first by PUM 0.   Six registers are used, and a maximum number of programming steps is 63 while statistical data is stored.  From the TI-65 manual, the following registers take the following values:

R1 = n * Σxy - Σx * Σy

R2 = n

R3 = Σy

R4 = n * Σy^2 - (Σy)^2

R5 = Σx

R6 = n * Σx^2 - (Σx)^2

Stopwatch and Timer

The TI-65, billed as a technical calculator aimed at professionals, includes a stopwatch and timer (but not a clock).  

Stopwatch:  

Press [ 3rd ] ( TUp↑) to start the stop watch.  Do this again to stop it.  

Timer:

Enter the time in hh:mm:ss  (hours:minutes:seconds) format, press [ 2nd ] ( TDn↓ ) to start the timer.   Do this again to stop it.   There are no sounds, the timer displays 00:00:00 when completed.  

You can store the timer into any available register. The store key is not required in this instance.   Recall the last time by pressing [ RCL ] [ : ].   

It may be possible to include the stopwatch and timer, however, they will not run in the background.   When the stopwatch or timer is working, the TI-65 is locked out of calculations.  Still, a nice feature.  

Closing Thoughts

I believe that the TI-65 is the penultimate calculator in the Galaxy series (the last is the TI Galaxy 67).  It's one of Texas  Instruments' most underrated calculators and production had continued into the 1990s, it could of had served as a non-graphing alternate to the TI-81.   Back in the early 1990s, graphing calculators were not as accepted in school; today, they are expected.

If you are collecting calculators, I would recommend the TI-65.  It's one of the best keystroke programming calculators Texas Instruments made since the TI 58/59, with a complete set of instructions and a decent amount of memory.  You do need a little patience because the TI-65 can be slow (especially compared to today's calculators).  The case and the sticker with helpful hints attached to it make a nice touch.  

(I don't recall the TI-67 Galaxy ever being on sale in the United States.)

Here are some TI-65 programs I posted in July 2016:

http://edspi31415.blogspot.com/2016/07/ti-65-programs-part-i-digital-root.html

http://edspi31415.blogspot.com/2016/07/ti-65-programs-part-ii-reynolds.html

http://edspi31415.blogspot.com/2016/07/ti-65-programs-part-iii-impedance-and.html

and will have more on tomorrow's post.

Sources:

Texas Instruments.  "TI-65 Technical Analyst" http://www.datamath.net/Leaflets/CL-947A_US.pdf     Flyer provided by datamath.net.  Last accessed April 10, 2022.

Texas Instruments TI-65 Technical Analyst Guidebook  1986

Toth, Viktor.  "TI-65"   rskey.org. 2022  http://www.rskey.org/ti65  Last Accessed April 29, 2022

Tschnenrechner-Sammlung, Tony   "TI-65 Galaxy"  Tony's Taschenrechner-Sammlung Calculator Collection https://www.thimet.de/CalcCollection/Calculators/TI-65/Contents.htm  Last accessed April 29, 2022

Eddie

All original content copyright, © 2011-2022.  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. 

Retro Review: Calculated Industries NautiCalc Plus

 Retro Review:   Calculated Industries NautiCalc Plus

Quick Facts:

Model:  NautiCalc Plus

Company:  Calculated Industries

Years:  1996-1998

Type:  Nautical

Batteries: 1 x CR-2032

Operating Mode:  Chain

Memory Registers: 10

Features

For a company that produces specialized calculators, the NautiCalc Plus is a rare calculator.   I purchased mine from Calculator Source's eBay page.   Calculations that the NautiCalc offers are:

*  conversions of time

*  conversions of distance

*  conversions of speed

*  triangulation calculations:  course direction, 1st bearing, 2nd bearing, distance of the bearing object, distance abeam

*  solver:  speed, distance, time

*  solver:  tank capacity in gallons, fuel efficiency (statute miles per gallon), range (how far can you travel with a fuel tank)

*  paperless tape with the capacity of 10 entries, accessed by the [ Rcl ] [ = ], which is not marked on the calculator.   Scroll the entries by the plus and minus keys.  

Memory Registers

The NautiCalc has ten memory registers, M0 through M9.   What is unusual is that the [ Stor ] key acts a memory-plus for M0.   For example:

[ Conv ] [ + ] (Clr Mem)

25 [ Stor ] 0  (M-0   25)

[ Stor ] 1    (M-1  25)

50 [ Stor ] 0  (M-0  50)

[ Stor ] 1  (M-1 50)

[ Rcl ] 0   (M-0 75)   75 is stored in M0,  50 and 25 were added together

[ Rcl ] 1   (M-1 50)   50 is stored in M1, 50 replaced 25 in M1

Miles

There are two measurements for miles:  statute miles and nautical miles.   Statue miles, also known as survey miles, are miles related to road distance, equal to 5,280 feet.   Nautical miles, which are used in sailing and air travel, are measure from 1% of 1 degree of the Earth's curvature (see source, "What Are Statute Miles?").   

Statue Miles:  [ Conv ] [ 7 ]

Nautical Miles:  [ Miles ]

1 nautical mile ≈1.1507794 statute mile

Entering Time 

Time can be entered with several ways:

*  [ AM ] and [ PM ] keys.  We can use the shortcut method hhmmss or hhmm format to enter time.

*  The colon [ : ] key.   

*  The use hours, minutes, and second keys ([ Hr ], [ Min ], [ Sec ]).  

The [ Conv ] [ : ] changes the time format between 12-hour and 24-hour military time format.  

If we want to enter degrees-minutes-seconds, we must use the [ d:m:s ] key.  

Stopwatch 

The stopwatch can be started and stopped with the [ Timer ] key twice.  The stopwatch also has a split/lap feature with the [ S/Lap ].  While the stopwatch is running, a clock icon is on the display.

Timer

The timer is started with pressing the [ Timer ] key, entering the time, then pressing the [ Timer ] key again.   The NautiCalc Plus has a buzzer, not very loud, that can be turned on and off.  While the timer is going, we see a clock and star on the display.  The entire display flashes when the timer is completed. 

Not many calculators as a whole have the stopwatch and timer, so to have it is a nice feature.  

Now let's demonstrate some of the main calculations that are done wiht the NautiCalc Plus.  

Example:  Fuel Efficiency

If a tank can carry 15 gallons and has an average efficiency of 30 miles per gallon, what is the range?

[ On/C ] [ On/C ]

15 [ Conv ] [ Speed ] (Cap) (display has GAL)

30 [ Conv ] [ Time ] (Eff)   (display has MPG)

[ Conv ] [ Dist ] (Range)

Result:  RNG:  450 MI S  (450 statute miles)

Example:  Distance of Objects and Abeam

Traveling with 30° course with bearings reading 45°12' and 58°42', respectively.   You have traveled 5 nautical miles.   Find the distance bearing from the bearing object and distance abeam.  

[ On/C ] [ On/C ]

30 [ Course° ]   (CRSE)

45 [ d:m:s ] 12 [ 1stϕ ]  (BRG1)

58 [ d:m:s ] 42 [ 2ndϕ ] (BRG2)

5 [ Miles ] [ Dist ] (DIST   5  N MI)

[ Dist ]    (Display:   TRVL 5  N MI)

[ Dist ]    (Display:  DOBJ 5.6156432 N MI)

[ Dist ]    (Display:  BEAM 3.1139547 N MI)

TRVL:  distance traveled

DOBJ:  distance from object

BEAM:  distance abeam

Example:  Speed/Time/Distance 

If a boat travels 13.5 nautical miles and it took 2 hours 23 minutes, what is the speed of the boat?

[ On/C ] [ On/C ]

13.5 [ Miles ] [ Dist ]

2 [ Hr ] 23 [ Min ] [ Time ]

[ Speed ] 

Display:  SPD 5.6643357 K NO T  (5.6643357 knots, 6.5184011 miles an hour)

Closing Thoughts

The keyboard is solid with the keys have a nice feel to them.  The NautiCalc Plus comes with a protective wallet, where the user guide can fit in the pockets.   

I really like this calculator and how Calculated Industries makes calculators for specific applications.  I would have loved to have seen the NautiCalc had a longer life than it did.   It's really cool to collect.  

I'm now retired from purchasing vintage calculators online.  I still will be posting retro reviews in the next few months, including the recently purchased the Texas Instruments TI-57 LCD (1982) and HP 45 (1973).  I am also going to include calculators that have been sitting in the garage that I didn't get a chance to do a review on, such as the Radio Shack EC-4026 (Casio fx-4500P equivalent) and TI-65.  

Source:

Bollman, Mark.  "NautiCalc Plus" April 21, 2013.   Last Accessed March 24, 2022.  http://mathcs.albion.edu/~mbollman/CI/NCalc+.htm  

Jones, Louise.  "What Are Statute Miles?"   Sciencing.  April 25, 2017.  Last Accessed March 27, 2022.  https://sciencing.com/statute-miles-8358166.html  

Until next time,

Eddie

All original content copyright, © 2011-2022.  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.