I'm a Texas Instruments graphing calculator programmer, specifically for the 83+ series, but also for the 73, 86 and partly 89.
You can also find random stuff in the /calcstuff/ directory of this site.
Various projects I'm working on:
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.
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):
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:
|276-1604||PNP Amplifying Transistors (15-Pack)||1||$2.59|
|276-1617||NPN Transistors (15-Pack)||1||$2.59|
|276-1770||+5V Fixed-Voltage Regulator 7805||1||$1.59|
|271-1321||1K Ohm 1/4-Watt Carbon Film Resistor5 Pack||1||$0.99|
|271-1311||100 ohm 1/4W 5% Carbon Film Resistor pk/5||1||$0.99|
|271-1335||10K Ohm 1/4-Watt Carbon Film Resistor5 Pack||1||$0.99|
|271-1315||330 ohm 1/4W 5% Carbon Film Resistor pk/5||1||$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: