range of a range-finder

This is the range of the rangefinder we ordered, with 1 foot by 1 ft by 1 ft square of the grid.

The problem I am trying to tackle is that signal is too easy to trigger in the area that is close to the device. That means the beam above is not sharp enough for me, and the it is too sensitive than I want.

The way I am working on is to store the signal value to a secondary value and then compare it with the signal reading in the next loop. if the difference is large enough, the servo doesnot turn.

So the problem is to find a good threshold for this difference.

choice of battery

In the choice of rechargable or non-rechargble batteries, we has to consider the consumption. If few and small servos are used, then non-rechargble can be a good choice because other parts will break before the batteries run out.

This can be tested if you scale up the frequency that servo is pulsed, which means, if servo turns 100 times a day, but instead you make it turn 700 times a day, you are actually simulating a week of operation.

However, as we are using strong servos, a 9V Energizer battery 150mAh would support no more than a few days, when audience actively participated.

make broken ones work

The key idea in our project is using broken solar cells. People know solar panel is a source of green energy, but the manufacturing and the material itself is not very environment friendly. So the maximize itself life by re-use broken ones is in essence reduce pollution.

This is the pack and cells we ordered. And it showed 0.273V inside.

The most amazing is, the reduction in voltage by further breaking the solar cell into pieces is not large. Although the max current is reduced, it is not a big issue in charging battery (but a issue in electric grid, which desires high current as well as high voltage).

pv cells go into here:

then in larger arrays:

self-protective mimosa

Our group is trying to incorporate a flipping mechanism of our solar cells, inspired by the mimosa's response to human touch.

before and when human approaching:　　　　　　　　　

indoor lighting and prism

Since we have problem of the lighting in the gallery, this might be a potential solution.

However, it is strongly weather dependent!

fly to the sun

This a mini robot design. I interpret this as a dream of brave human to getting closer to the sun, by using solar energy on the way, although it will be getting hotter and hotter.

http://www.schuelke.org/sko11.html

about productivity

Meeting today is a productive one because we decided who does what.

Everybody has devoted a lot of time in this and maintain a high expectation.

But one thing may be different bet/ engineers and designers is , we figure out more during the experiments while designers tend to prototype when ideas are fully developed.

This is one of the way of doing this I learned here.

But we will get hands on once materials arrives, not wait until the last week.