I just ordered my first Teensy 3.1 along with a 60 LED strip from Adafruit. I also picked up the 74AHCT125 that Adafruit had in stock and recommended to step up the logic to 5v. So far, I cannot get the LED strip to light at all. I have tried with and without the 74AHCT125 (some places said they might work without it, at least enough to test). I have tried using the strandtest with the adafruit neopixel as well as just changing a couple of pixels according to their code.

Okay... so in uploading this I realized I left off the ground on the LED logic. I know it isn't in this picture, but I know for a fact I tried it with the ground. I removed some excess components and wires before taking this picture and going to bed, so I must have accidentally removed it.
Some other details: the Teensy works fine otherwise in the current setup. I have separated the VIN and VUSB pads and power it only from a 5v/2A wall wart. I can write programs to make standard LEDs light, blink, etc. I know the LED strip is getting power because some of the LEDs flash when I plug in the barrel connector. The logic cables from the LED strip are snug in the bread board but I have also connected them more directly to test. I have also tested with and without the resistor on the logic cable. If it matters, I'm using the latest Arduino and Teensy software (downloaded last night) on my Mac. I may try it on my Windows computer tonight.
If we assume it doesn't work with the ground there, I have a few questions:
Thanks for bearing with me and my many questions. This is kind of a totally new world for me, and I'm excited to learn it.
I will connect the ground up correctly tonight and tinker with it some more.
Thanks for your help!

Okay... so in uploading this I realized I left off the ground on the LED logic. I know it isn't in this picture, but I know for a fact I tried it with the ground. I removed some excess components and wires before taking this picture and going to bed, so I must have accidentally removed it.
Some other details: the Teensy works fine otherwise in the current setup. I have separated the VIN and VUSB pads and power it only from a 5v/2A wall wart. I can write programs to make standard LEDs light, blink, etc. I know the LED strip is getting power because some of the LEDs flash when I plug in the barrel connector. The logic cables from the LED strip are snug in the bread board but I have also connected them more directly to test. I have also tested with and without the resistor on the logic cable. If it matters, I'm using the latest Arduino and Teensy software (downloaded last night) on my Mac. I may try it on my Windows computer tonight.
If we assume it doesn't work with the ground there, I have a few questions:
- Is there anything obviously wrong with my setup?
- Should I be able to use the 74AHCT125?
- Am I using the 74AHCT125 correctly?
- Is the Adafruit neopixel library what I should be using right now, or is there something better for troubleshooting?
- Should I be able to use these LEDs at all without the 74AHCT125 for testing purposes?
- What should my next steps be to troubleshoot this?
- Is there any functional difference running the Teensy and Arduino software on Mac vs Windows?
Thanks for bearing with me and my many questions. This is kind of a totally new world for me, and I'm excited to learn it.
I will connect the ground up correctly tonight and tinker with it some more.
Thanks for your help!