No. Just buy your extremely cheap and long distance USB extender: http://www.monoprice.com/products/subdepartment.asp?c_id=102&cp_id=10303&cs_id=1030312

They have HDMI ones too http://www.monoprice.com/products/subdepartment.asp?c_id=109&cp_id=10110&cs_id=1011012

So...what is this "time it took" you intend to measure? I hope you're not trying to measure time-of-flight of a laser pulse with an Arduino.

Muscle wire would be cool, but just a little tricky. Probably the easiest way is to mount this thing on a vertical tube, which is in turn mounted to a base containing the electronics. The wings are mounted to a yoke arrangement as shown in zoomkat's post, and a wire would run down to a small RC servo mounted in the base. Same idea as those robot grabber sticks.

None of this should be happening. By any chance are you trying to run the LED displays from the Arduino's regulated 5V?

I don't see the same value, I see it setting register address 3 for the get_date function, and register address 0 for the get_time function.

The requestFrom lines are correct because immediately prior to the day/month etc request, the starting address register is written to the device.

Are the pads somehow not on the bottom? Because with a "single sided" board (which seeedstudio doesn't normally do), it doesn't matter what side the traces are on if the pads are actually double sided and through plated. The circuit is the same. If you actually only sent one copper layer file, then yeah...one side would be missing the pads.

Yes, ElcoJacobs ShiftPWM is nicely done!

I won't have the high density WS2811 in stock for while. Still have the 30px/m and the 60px/m in waterproof (possible to just slide the strip out of the sleeve). I think several other vendors have it, too.

It depends how far apart you want the columns to be. If you can't use 32mm spacing or 16mm spacing, then the WS2811 strips won't work without a lot of cutting and rewiring (which wouldn't be too bad for only 60 pixels). It'll probably actually be easier to control all the RGB LEDs individually rather than trying to have groups of three controlled together...such is the state of available pixels strings and strips these days.

Attitude, Google, 150 wires...let's throw all that out.

The main piece missing here is how you want to arrange these LEDs. How bright are they, should they be clusters or single LEDs, how far apart should each pixel be, how bright, etc.

Trying to control 150 wires' worth of PWM is not the best approach here. You need smart pixels, which come in a wide range of types. They will communicate down a single chain of wires using a serial communication protocol. You can actually just buy premade pixel strings with 25 or 50 pixels on a wire, spaced 4" apart. Look for WS2801, WS2811, etc. I also sell LED stuff like the ShiftBrite which is more modular as you chain them together with pluggable cables. The WS2811 strips are also really great because they are really cheap and you can cut them up and rewire as needed.

AND make sure it's set to LOW. Setting it HIGH will enable a pullup, and then it's a fourth state: weakly on.

I made some long ago using a traditional strobed matrix approach. These use two AS1130 (on the BGA WL-CSP package) and are way more capable.

Easy to see through them.

Writing code for some RGB ones now But those aren't relevant to AS1130.

 

I'd also make sure you aren't trying to reset the seconds register every time the PPS signal triggers.

If you get really fancy, you might be able to create an iterative routine that monitors both pulse outputs, and adjust the delay to account for I2C timing until they're as in sync as the Arduino can measure. Perhaps even measure the drift and trigger another re-sync cycle when it's more than 1mS off.

I have no idea if 120mm is a hard limit; if so, the design I posted is a bit oversized at 124mm without accounting for an additional black border around it. So with the WS2811 pixels, you would either need to go 6x6 and fill in the edges diagonally as best as possible, or look into creating a custom PCB with closer spacing (10mm, 12mm, etc). That actually not out of reach, assuming you buy from Seeedstudio or another place with cheap PCB prototypes.