Hello..is this thing on?

I moved house for the third time since arriving in San Francisco and unfortunately I am having trouble connecting to the internet. I may not make many more posts for the remainder of my stay here. I'll at least endeavour to post a wrap-up at the end when I am home.

In any case deadlines are tightening and there is a long way to go. People are starting to count the time until the work needs to be shipped in days. Less than a month to go and the main feature Big Stumpy has not been completed. We haven't even finished layer A, and I have been working on it since I arrived. The work is becoming more repetitive and urgent.

I'm still trying to get as much out of my stay as possible but it looks like I'll be leaving before either the plumbing or the lighting are installed into the sculpture.

I spent some time with the Geeks today. We did a few things. I assembled some parts for the small "brains" that run some of the lighting - a small computer board called a Raspberry Pi.

An assembled Raspberry Pi

 Then our attention turned to the newly arrived LED strips. These are strips of single LEDs along a cable that can emit colours in any of the RGB spectrum. These will be placed in the Light Mushrooms and will have various patterns  flashing through them.
The main effort today was to make them run. So we jigged up a bunch of wires, a regulated power supply and an Arduino linked to a laptop and tried to make these little blighters flash. A few loose connections later, success!

Flashing LEDs

 A little bit of technical background. The effort was to see how much ampereage the LEDs would draw and to make sure that all the componentry would work together. The LEDs are rated at 5 volts. The regulated power supply converts 220v to 12v so there needs to be a   way to step the voltage down to 5v. This was done with a small integrated circuit plugged into a breadboard.

So the LEDs work but when we switched to white light (RGB 255/255/255) there was a very evident loss of brightness and colour further away from the power source. This was attributed to a voltage drop with distance so power was also applied from the other end. Success! The white LEDs shone with almost equal brightness the whole 4m distance. There was a slight fall in brightness between them so we spliced another power link into the middle. The benefits gained from this were not significant, and in any case the lengths never need to be longer than 2m so they will always have ample power from either end. So I guess that was a successful day for the Geeks!

Then I went back to welding more bark onto Big Stumpy....