Video Entry for IdeaSpace Startup Competition 2014

IdeaSpace – Salt-Water Powered Lamp from Aisa Mijeno on Vimeo.

Over 1.5 billion people rely on kerosene for light. Lack of suitable home lighting is directly linked to illiteracy, poverty and health problems. The current widespread burning of kerosene also results in environmental pollution. Fuel-based lighting (typically kerosene) represents $38 billion per year in fuel costs and 260 MT of carbon-dioxide emissions worldwide.


This written publication had been submitted as part of an IP Disclosure for Record and Evaluation form. All copyrights reserved to SALt founder.

SALt or Sustainable Alternative Lighting is an ecological lamp design operated by tap water and table salt. It uses the open Science behind electrochemistry, the basis of battery-making and a joule thief design altogether to produce an efficient lighting system with luminosity on-par with battery-operated lamps. Sustainable Alternative Lighting is composed of two different metal elements, combination of Cu (Copper) to act as the cathode and either of the following elements – Zn (Zinc), Mg (Magnesium), or Al (Aluminum) to act as the anode.


Figure 1.0 Electrochemistry Illustration

As shown in Figure 1.0, the element Zn has been used as the anode and Cu as the cathode of the Galvanic cell system. The chemical reaction of the following metals toward salt-water solution will produce electricity enough to power-up a 5mm LED.

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Figure 2.0 Electrochemistry Experiment (Principles of Galvanic Cells)

Figure 2.0 below shows the experiment done using an ice-cube tray as a temporary container for the salt-water cell. The whole 14-cell produced 6v enough to give the 12v LED bulb a faint light.


Figure 3.0 Joule Thief/Ringer

The design however, still need the aid of an electrical circuit we call “Joule Thief” to attain the utmost luminosity level of a 12v LED bulb. Figure 4.0 shows the joule thief, sometimes called ringer. Joule thief is a circuit designed to oscillate and increase voltage that is easy to build, small, cost effective; and typically used for driving light loads like LED bulbs and fluorescent lamps.

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The joule thief/ringer, which is composed mainly of ferrite toroid with wound magnetic wire will be the means to power up a 12v LED bulb. The diameter of the toroid and the number of turns would determine the produced inductance which in return would give us the voltage output.

To understand deeper the principles of joule thief, for step up and step down transformers, inductance is solved by the square of the number of turns in wire coil multiplied by permeability of core material and area of coil in square meters which will then be divided into the average length of coil in meters.

L = (N2µA)/l    

L = Inductance of coil in Henrys
N = Number of turns in wire coil (straight wire = 1)
µ = Permeability of core material (absolute, not relative)
A = Area of coil in square meters
l = Average length of coil in meters

To get the voltage from inductance, according to Ohm’s Law for an inductor, voltage is equals to inductance multiplied to the instantaneous rate of current change.

v = L(di/dt) 

v = Instantaneous voltage across inductor
L = Inductance of coil in Henrys
di/dt = Instantaneous rate of current change (amps/sec)

The above formulas will determine the diameter and number of magnetic wire turns to produce the correct output voltage of 12v. To summarize the toroid concept, the more magnetic wire you wind around the ferrite toroid, the higher voltage you produce.

werwerFigure 4.0 Joule Thief Experiment

Figure 4.0 shows the joule thief experiment we did to show how much voltage we can increase using this method. Coming from a voltage of 2.4v, we were able to amplify it to 16v which was able to power-up the LED bulb to its full potential. We will be creating our own design of joule thief to achieve just about the right size and compactness for the design. This method will also likely prolong the life of the electrodes that we will use in the lamp.


We are not just doing this for the environment, but we are also doing this for the people who do not have access to any electrical facilities.


Above will be one of our initial beneficiaries, the Hanunuo Mangyan tribe from Bulalacao, Oriental Mindoro who do not have the capability to sustain a monthly payment for electricity and just need a decent light to survive the night over



Working Time: 8 hours continuous, 1 cup of water/1 teaspoon of salt

Consumables: Anode rod, every 6 months for continuous usage

Luminosity: 320 lumens, comparable to 4W LED bulb



One comment on “Product
  1. This is great! Congratulations guys.

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