WiKiPi – Final Presentation outlines

Posted on April 25, 2013 by admin

In the Beginning

Shared interest in the idea of a Library on principal.
concern for grid-independent, preserved and personally accessable information.
Wikipedia not a bad place to start.

Overview of Modules

Module A : Bicycle & Generator
Module B : Battery & Charge controller
Module C : Voltage Regulator
Module D : Raspi, Kindle, Keyboard

System as a Whole

OG WiKiPi: Off Grid Wikipedia + Kindle + Raspberry Pi

Discuss & Demonstrate power flow – inputs & outputs, starting with the food a cyclist ate that day.
losses, power output, time required to charge battery
hHow long power can be provided to the system.

Technical Disection

Anne-Marie on schematics : build and functions of both charge controller & voltage regulator
Jay on Raspi & kindle.
Shared discussion about bicycle generator > outputs & inputs.

Design Decisions

Custom VR vs Inverter: Inverter is awfully inefficient and fails when battery drops under 12v.
Also: a. We want to learn how to do it ourselves.
b. Cost.
Kindle Screen – no refresh. very low power draw.
Raspi – obvious. Low, low power, flexibility of full OS with linux world.
Bicycle vs. Solar / Wind – Control. Power input not abstracted away. The system functions both indoors / and outdoors which can’t reliably be said for solar / winds.
Small Battery – Sufficiently proves the Concept. and helps to keep the whole project semi-mobile.

Cost Overview

What it cost

Discussion on Versatility & Next Steps

Voltage Regulator could power phones, etc
Broadcasting via Pi
Different Pi SD’s could contain software for different communcation systems – BBS, Phone, Web, Etc

Generating Electricity using the body heat

Posted on March 28, 2013 by admin

Here is the .pdf version of my in class presentation. Energy Presentation

OGWP – Mid term

Posted on March 14, 2013 by admin

[Generating energy]
DC motor: Voltage 24 volts. Power 250 watts. Rated speed 2750 rpm. Rated current 13.5a

In order to have the wheel-roller spinning as evenly as possible, we ran a positive current through the motor, using it as a lathe.

We then measured the voltage we could produce without any load. Bicycling lazily, Jay could produce 15 volts.

[Powering the Raspberry Pi]

We bought a 12 volts rechargeable battery that will eventually be recharged by the bike-powered DC motor. Here are the battery specifications:

Battery: enercell sealed lead-acid. 12 VC. 7.ah. Normal charge 14.4-15 OV. Stand by 13.5-13.8 V.

We built a circuit that could regulate the voltage down to 5 V using the following:

Battery -> 100uF -> 7805 regulator -> 100uF -> 1uF -> Raspberry Pi

WE used this circuit to power the Raspberry Pi

Raspberry Pi draws .500a to .700a to boot.

It took Cycling for 1:52 to fully charge three 2.5VDC Capacitors in Parallel.

Video sculpture – Mid term

Posted on March 8, 2013 by admin

flow

OFF.Grid WIKI-PI – Mid Term Project

Posted on February 28, 2013 by admin

A Project by Jay and me. Illustration by Jay Zehngebot.

The Context
When the tsunami hit Japan in 2011, we recalled reading news about a hand-written newspaper.

“Unable to operate its 20th-century printing press — never mind its computers, Web site or 3G mobile phones — the town’s only newspaper, the Ishinomaki Hibi Shimbun, wrote its articles by hand with black felt-tip pens on big sheets of white paper.”

Late October 2012, Hurricane Sandy hit New York City. We were in Manhattan when the city shut down the subway the Sunday before the storm. For the whole of Monday we managed to work – with power and access to the Internet. The power went off in the evening, around 8pm.

At first it was nice; being disconnected from the entire world. We connected to another one: life without access to information. For the 4 days we stayed in the Manhattan blackout, I realized how dependent on power and the Internet we are. We had no paper dictionaries, no encyclopedia, basically no resources to learn/verify/read.

“When I was a kid, we had blackouts, and we didn’t have internet then, but it was the first time I had to face how dependent I am on the internet. Since i’ve moved to the city, I don’t have any books”
- Anne-Marie

The Project
We like bikes. We bike anyways. Post-Sandy, stated simply, we want a bicycle-powered computer.

furthermore, as we proceed towards a cloud-based network structure, we loose localized access to information, files, resources, and applications

We’re not aiming to build a gridless-internet with this project – but instead, maintain a link to knowledge. If the power goes out, we want to arm ourselves with information.

to this end, the Raspberry Pi is an exciting platform. Low-power Linux offers a number of options.

Some diy bike-powered battery projects have been put out there already. Like this one, or this other one.There is also this bike-powered cellphone charger.

We will build on those previous experiences and will try to set up a system that can power the Raspberry Pi with the lowest COH (cost for harvesting) and for the longest time.

Lab Week 5 – operational amplifier

Posted on February 26, 2013 by admin

During this lab, we have built a unipolar amplifier, meaning that it accepts only positive voltage.

In the ideal world, an amplifier would give an output equivalent of the input in voltage. We still get that in the real world, but the output is not only audio. It has interferences that cause the quality of what has been amplified diminish. This is because the gain decreases when the frequency increases. The higher the frequency, the lower the gain. So before you set up an amplifier, you need to know at which frequency you need you output to be. Than, you set up your gain accordingly.

(graph to come).

The gain af an amplifier is set using two resistors. One of the resistors is connected to the output and sends a feedback to the negative input. The feedback sent determines the gain. If you send a feedback of 1000k to negative power connected to a 1k resistor, then the gain if 1000k. The equation is:

resistance of the feedback / resistance of the resistor connected to negative power = gain.

(graph to come)

For the lab we used a LM358. This is a dual amplifier, but we used only one.

Here is the schematic of the circuit we built.

Lab Week 4 – LED Flasher/555 LED Breather

Posted on February 26, 2013 by admin

Moby dick – A Pop-Up Book

Posted on February 23, 2013 by admin

This book by Sam Ita uses interesting combinations of pop-up techniques which compensate for a weaker writing style. The following is a attempt to describe the paper techniques used by the author. I have to say, it is sometimes not easy to isolate each part to describe it, as all the parts are tangled up to create the shapes. I am sure I made mistakes and sometimes did not use the right term to describe the techniques used. But nonetheless, analyzing an existing book is a really instructive thing to do.

Page 1 – The boat

The first page displays 4 sections of pop-up techniques:

the boat: the deck of the boat is a floating layer combined with 2 reversed scenery flats for the shell. The mast are the continuation of the floating layers support structures.
Ishmael: he is standing on a floating layer. His body is made of a 90 degrees angle fold combined with a parallele cube technique.
Yojo: the hand opens and displays a 90 degree combined with a mini valley fold to make the spear rise.
Ishmael in bed: the bed is made of the parallel cube technique using a 90 degrees mountain and valle fold to make his head rise.
Yojo: to make the door open, a tab with parallel movement has been used.

Page 2 – The Church

This page displays 4 sections of paper techniques:

the audience: a combination of parallel planes and scenery flats are being used.
the priest: he is standing on a floating layer. His body is glued on a 180 degrees parallel cube technique. The boat shape: it is made of a valley fold scenery flat with tipped-in extensions.
the beast: it is a small section, but an interesting one. The head of the beast seems to be a cube technique used at an angle. The tail is a mountain fold. The man inside the beast is based on a tube post armature and his arms moves because they are touching the the background that is made of a parallel fold.

Page 3 – The Captain

This page has 3 different sections:

the captain: the body is made of a valley fold horizontal v. and the rest of the body is made of typed in extensions combined with mountain and valley 90 degrees folds.
the seamen: they are on a floating layer that is activated by a a pull tab using pivots.
the whale: the whale is a combination of valley folds and cube technique. The boats are made of the boat shape and two of them are using a lever.

Page 4 – The Boats and Ocean

this page has 4 sections.

boats and ocean: the white whale is a simple mountain fold. The waves are made of valley mountain angle 180 degrees fold. The boat on the left page is a 180 degrees boat structure. The boat on the right is parallel plane with a mountain 90 degrees fold.
the man with the gull: the gull is a mountain fold with the head of the gull attached to a parallel plane.
the captain on the map: is made of a pull tab with a lever.
the coffin: Yojo is made of a angle fold box with a crossing plane. There is a parallel plane for the coffin maker.

Page 5 – Moby Dick

This page has three parts.

Moby Dick and the boat: the whale is a box attached to a small floating layer. the boat is made of two floating layers. the broken mast is sort of a floating layer attached to the continuation of the armature of the base.
the small whale: is a box and a 180 degrees fold for the wave that rises.
the spinning water: it is a wheel using the changing picture technique.

Page 6 – The spyglass

image to come soon.

The spyglass is a combination of 3 boxes. The hand is tipped-in extension attached to a floating layer.
Ishmael in the water is made of a floating layer for the water and small valley fold for the rotation of his body. The rescuer is made of an angle fold platform.