Personal Learning Tool: The PET Project

Intel’s co-founder Gordon E. Moore observed already in 1965 that the number of transistors placed on an Integrated Circuit is increasing exponentially, doubling approximately every two years. The trend has continued for more than 40 years and is known as “Moore’s Law”. 

If we try to apply Moore’s Law on graphing calculators, we should focus on two products:

TI-81: Texas Instruments entered the market of graphing calculators in 1990 with this famous product.
TI-92: Announced in 1995 but available in 1996 the TI-92 was the first symbolic calculator with 
   Computer Algebraic System (CAS) based on Derive.

It took six years between the availability of the two calculators and we would expect based on Moore’s Law an 8-fold (doubling every two years) improvement of some features. Just by extrapolating another six years we would expect a “next-generation” Personal Learning Tool in 2002. Learn more about the Hardware Architecture of TI’s Graphing Calculators.

What would we predict?

  TI-81 TI-92 Prediction Comments
Introduction 1990 1996 2002  
CPU 8-bit
In 2002 we would expect a ARM-based architecture
CLOCK 6 MHz 10 MHz > 30 MHz The use of C-language asks for lot of MIPS!
DHRYSTONE 0.2 MIPS 1.0 MIPS  > 30 MIPS A common benchmark for CPUs
RAM 8k Bytes 128k Bytes > 2M Bytes User Interfaces are memory hungry
ROM 128k Bytes 1M Bytes > 8M Bytes Lot of functions and languages
Display 64 x 96 =
6k pixels
128 * 240 =
30k pixels
320 * 480 =
154k pixels
Displays don’t follow Moore’s Law

And Texas Instruments developed it!

After publishing some information the PLT SHH1 labeled prototype in February 2007 the Datamath Calculator Museum received a lot of vague information about a canceled calculator project from “undisclosed sources” but in February 2008 Texas Instruments put everything into perspective. 

PET_Overview.jpg (230706 Byte)The Datamath Calculator Museum received a total of 6 unique and exciting products as a loan from Texas Instruments in February 2008 to photograph and document it. We learned from Texas Instruments that they developed between 1998 and 2003 a family of next-generation Personal Learning Tool products based on the LINUX operating system. The Dallas, TX based team nicknamed the project PET and we know:

PLT SHH1: Spot Hand Held, first generation PET device with smaller, portrait oriented screen.
PLT DS1: Data Sled, cradle with USB connector for the PLT SHH1
PLT WS1: Wireless Sled, cradle with wireless LAN and USB connector for the PLT SHH1
PLT FHH1: Fido Hand Held, first generation PET device with larger, landscape oriented screen
PLT USB1: Universal Serial Bus Module for PLT SHH1 and PLT FHH1
PLT SU1: Toto Hand Held, second generation PET device with large color screen
PLT VIEW: Presentation Adapter connects PLT SU1 wireless to a VGA monitor 
PLT WC: Wireless Card for the PLT SU1 and PLT VIEW to establish a wireless LAN according to the IEEE 802.11b standard
PLT IRDA: Infrared Communication Card for PLT SU1 according to the IrDA standard

We assume that about 500 prototypes of the PLT FHH1 were used for field tests at different sites and most of them made their way back to Dallas, TX. The PLT SHH1 seems to be even rarer, only about 50 prototypes were used for tests. The PET project was cancelled before the 2nd generation PLT SU1, nicknamed Toto was prepared for the field and according to Texas Instruments not even one prototype left the company (except for this loan).

At first glance a wonderful family of next-generation Graphing calculators was halted but there are some drawbacks.

Both the PLT SHH1 and PLT FHH1 are over-designed for the math functions. A TI-83 is much easier to use.

LINUX as an operating system seems to be attractive from an engineering point of view, but imagine kids hacking into the calculator. Good for a learning tool but not acceptable for exams.

Lessons Learned:

A graphing calculator used in math tests or standardized achievement tests for college admission is a “testing device” and has to be a secure system. Teachers should be able to clear or disable programs and applications stored on students calculators. 

Texas Instruments worked secretly on the Phoenix 1 and announced in 2006 the TI-Nspire CAS+, but it took another year before the long-awaited TI-Nspire calculator family arrived finally July 2007 in the store shelves. The PET program provided Texas Instruments obviously with a lot of valuable lessons and insights that found its way into the TI-Nspire, e.g.:

Split-screen options 
Dynamic linking between multiple representations for interactive feedback
Computer like cursor supporting “Grab-and-Move”
Switch from Linux to Nucleus, a “closed” Operating system
Upgrades and downloads are sent as encrypted fiels to the calculator

If you are interested in canceled calculator projects, don’t miss the SR-40 Prototype and the TI-88

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© Joerg Woerner, March 8, 2008. No reprints without written permission.