I spent the evening with a good friend of mine, Matthew Flego an industrial designer, at his metal fabrication shop, Ferra Design in the Brooklyn Navy Yards. He and I plotted out the design for a 12 gauge stainless steal housing for the inDOOR Harvester module in Solid Works, a 3d object CAD application.

The file was exported to a water jet cutter, an amazing automated machine that uses water and ground garnet as an abrasive to cut through any material up to the 1000th of an inch. It perfectly cut the shapes with their , tabs, holes and score-lines for the brake to bend.

Next, I hand tapped all of the holes with 10/32 thread and then took it to the brake to form the sheets into the actual housing. Using up to 20 tons of pressure, the steal became paper like as it bent and curved under the jaws of the brake.

Matt & brake at Ferra in Brooklyn

the parts were then tig welded together, ground and surface treated.

tig welding

welding 2

then attaching the slide, generator and gear rack to match the prototype.

more images to post soon as it nears completion…


an online monitoring system

A glimpse at the revised version of the online dashboard monitor for the energy harvesting module.

It been a big javascript learning curve this past week, but well worth it.

Many more features and improvement still to come, as well as further data integration.

check it out – let me know what you think.

I’ve spent the last two week testing and researching linear motion guides, blocks and rails, to carry the gear motor along the door and across a rack. Due to exploding bearings and bent rails, McMaster-Carr has both saved my thesis and made a nice chunk of change. A far more effective and elegant system from the last version: a steel bracket on the wall side with a rotating clevis end holding a 1/4″ rod connects to the motor mount with another clevis rod end piece. I’ve also found a type 304 stainless steel side-mount ball bearing guide block and rail that’s able to with stand the pressure the arm exerts as it pushes/pulls the motor attached to the guide block as the door opens and closes (load capacity of 197lds). It also keeps constant pressure on the pinion gear against the rack. The gear has also been reduced to 1/2″, thus providing slightly more rotations within the motor/generator -> slightly more power out, thereby slightly more resistance to move it.


The circuitry seen on the left if a simple AC input from generator to a bridge rectifier that outputs DC to a 1F 5.5v storage capacitor. I also have a switch and LED to drain the cap for testing. On the breadboard is the testing and data logging circuit with an Arduino stamp connected to the capacitor. It sends out an HTTP requests through a Lantronix Ethernet port that calls a php script to insert the values into a mySQL database. On the back of the door I have installed a switch that the mico-controller uses to count the number of times the door opens.


next: looking into a light weight housing for the module for easy install and easy to look at.

Im working with an open source library for Action Script and developing dynamic graphs via php to grab data from a mySQL data base and visualize them, re-freshing when new data is input. First attempt with data input from an Arduino stamp sensing from a potentiometer (stand in for a capacitor) and uploading to mySQL via an XPort HTTP request – shown here. Mouse over the intersections – circles for a data window. This will be greatly expanded in the next few weeks – stay tuned.

here is the 5th version – a dash board monitor for the harvester.  this too will evolve.

story time


it went a little something like this:

“there is an old story about Thomas Edison.
Henry Ford was visiting Edison one day,
and found it hard to push open the front gate at Edison’s yard.
When Ford chided the world’s greatest inventor about his rusty gate,
Edison replied Ford had just pumped a gallon of water out of the well!”

– no new ideas, just new implementations.

When visitors came to his house, they passed through a turnstile that had to do enough work to raise a gallon of water to Edison’s roof holding tank.


I’ve just put together a php page that allows the user to quickly get an idea of what is happening real time as the inDoor Harvester prototype is operating. The left side has a table showing the data collected from a micro – controller attached to the harvester measuring the electricity storage in a capacitor (battery icon) as SI units of Joules. The Arduino stamp micro-controller is connected to the internet via a Lantronix Xport Ethernet port, which it uses to call a php script and pass it the values through the url. The script inserts the values into a mySQL database, provides it an id and a time stamp. The user can choose to sort the data by id, joule values (high to low) and by the date/time it was recorded.

On the right side is a Flash animation showing graphically what is happening. Programed with actionScript 2.0, the animation calls a third php script that grabs the last value posted every 10 seconds. The script controls two movie clips and two dynamic text fields to represent the electricity stored over time, battery level, as well as the amount produced the last time the door was opened and closed, light bulb icon. If the value has not changed, and it may not since the prototype is not installed yet and not constantly running, it will show the same thing over and over.

This is a work in progress and will change as the left and right side get their own pages and expand to include user log-in and multiple graphical representations of the data with resolution control.


Energy Graph



The available ambient power is the energy produced by the generator as the door opens and closes. Basic testing on the prototype with a dc-gear head motor with a 10:1 gear box and a 1″ spur gear running 12″ along a rack produces approximately 2.5v @ 184mA charging a 1F 5.5v capacitor.

The system power usage is the load on the circuit, which in this prototype is a small LED display pulling 3.3v.

The stored energy is the electrons stored with in a capacitor. The stored energy goes up as the generator is rotated from the door opening and closing. As the door remains either open or closed, the energy in the capacitor is slowly drawn and thus the amount lowers. Therefore, if the door is not moved over an extended period of time the energy stored will eventually be depleted, thus a voltage trigger is crucial.