I'm a Texas Instruments graphing calculator programmer, specifically for the 83+ series, but also for the 73, 86 and partly 89.

My ticalc.org author profile and the Detached Solutions home page have a little more information about me and the calculator community.

You can also find random stuff in the /calcstuff/ directory of this site.


Various projects I'm working on:

documentation and stuff

Here are some random things I've discovered or created and that might be of some help. I make no guarantee on its accuracy or completeness, though.

hardware modifications

Alex Forencich developed a power circuit for the 84+(SE)/89Ti USB port to make a cable that can break the 100mA power limit they currently have (no pun intended). It gets the power instead from a 9V battery. I built this circuit and can verify it works, but I made several part substitutions so that all the parts can be bought from Radio Shack.

Below is Alex's original power circuit (click for bigger image):

>100mA USB power circuit

D2 can be substituted with another 1N914 diode, Q1 can be substituted with the 2N2222 NPN transistor, and Q2 can be substituted with the 2N3906 PNP transistor. You'll also (naturally) need mini-A male and A female USB cables to splice. One end of the unit-to-unit USB cable that comes with the 84+(SE) and likely 89Ti will work for the mini-A male part.

A complete list of parts (as best I could match off radioshack.com) is below:

Part NumberDescriptionQuantityPrice
276-1604PNP Amplifying Transistors (15-Pack)1$2.59
276-1617NPN Transistors (15-Pack)1$2.59
276-1770+5V Fixed-Voltage Regulator 78051$1.59
276-11221N914/4148-Type Diode1$1.39
271-13211K Ohm 1/4-Watt Carbon Film Resistor5 Pack1$0.99
271-1311100 ohm 1/4W 5% Carbon Film Resistor pk/51$0.99
271-133510K Ohm 1/4-Watt Carbon Film Resistor5 Pack1$0.99
271-1315330 ohm 1/4W 5% Carbon Film Resistor pk/51$0.99
Total Price: $12.12

You can probably buy these parts for far less elsewhere, but if you're in the middle of nowhere, this should be the highest it'll ever get.

Here is a picture of the completed circuit, prettied up as much as possible:

my >100mA USB power cable