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Introduction
Energy is collected from natural sources to be accumulated and stored, to later be used for a special purpose. In a city in Colombia there is a proliferation of telecommunications antena located in a different community, with significant amounts of radio frequency that is possibly affecting the health of its inhabitants. The above is considered as an opportunity to identify a type of prototype or important elements that lead to the construction of an energy harvesting system with the amount of radio frequency existing in the context that will later be reused.
Problem
There are 71 telecommunications antennas located in different communes in a city in Colombia, with the concern that it does not use the budget for decree 0162 of 2014. On the other hand, the research by Tovar (2015), carried out at the Cooperative University of Colombia in The city of Neiva has 83% of those that fail to comply with the decree to be implemented in the city. With the foregoing, the increased risk to health is logical, due to noncompliance with the standard, the generation of non-ionizing radio-frequency electromagnetic fields (EMF-RF) is evident [1]. Worldwide, people require electronic devices for their daily activities, interacting with electromagnetic fields constantly and without realizing they are experiencing a type of invisible pollution that radiates from their bodies. In the case of mobile devices such as smartphones, they require radio frequency (RF) waves. These RF waves are different from the types of radiation (ionizing), such as X-rays, gamma rays, ultraviolet light, which break chemical bonds in DNA. RF waves at high levels can heat the tissues of the human body.
Objective
Design of an energy capture system for use in the surroundings of the communes that present concentration of Radio Frequency (RF) waves in a city in Colombia.
Methodology
For the development of the research process, a qualitative methodology is used, and as part of the information gathering techniques, a technical sheet and the design of a prototype for energy collection are used. The collection of energy occurs in small amounts as a product of light, heat and vibrations, thus improving the use of energy available in the environment, to be accumulated and stored [2].
Sunlight and mechanical vibrations are fundamental elements for collecting RF signals obtaining clean energy through electromagnetic waves radiated from various communication systems, finding that RF and microwaves receive a great impulse [3].
Free energy is the energy found in the environment but in quantities that cannot be used in work, for its collection an energy capture system is used to then condition, store it and be able to use it as shown in Figure 1, RF-based energy harvesting architecture takes advantage of the large number of antenas located in the different communes of the city as shown in table 1. The trend is to be able to collect energy by RF with the designed prototype that uses electromagnetic waves using an antenna and converts it into direct current that will be charged wirelessly in different low-power devices.
Table 1 Antennas by commune.
| Commune | Amount of antennas | Owner |
|---|---|---|
| 1 | 7 | Tigo, Movistar, ETB and claro. |
| 2 | 3 | Claro. |
| 3 | 9 | Tigo, Movistar, ETB and claro. |
| 4 | 14 | Tigo, Movistar, ETB and claro. |
| 5 | 7 | Tigo and claro. |
| 6 | 8 | Movistar and claro. |
| 7 | 6 | Tigo, Movistar and claro. |
| 8 | 6 | Movistar and claro. |
| 9 | 6 | Movistar and claro. |
| 10 | 5 | Claro. |
Next, the electronic devices that make up the circuit shown in figure 2 are described.
Antenna: it is a normally metal conductive device, designed with the aim of emitting and / or receiving electromagnetic waves from the air to process them until a direct current is achieved. The RF is in a range of 30 Hz to 300 GHz. Therefore, it is convenient to use an antenna that captures VHF (Very High Frequency), frequencies that occupy the range of these frequencies [4].
Capacitors: a capacitor is a passive electronic component in an electrical circuit that connected to other electronic devices is responsible for storing energy. Capacitors together with the help of a diode can convert alternating voltage signals into direct voltage [5].
Diode: a diode is a semiconductor-type electronic component that is essentially used as a switch to the current in only one direction. Its function in an electrical circuit is to allow current to flow in one direction, but it does not allow current to flow in the opposite direction. Diodes are also known as rectifiers because they change signals from alternating current (AC) to pulsating direct current (DC) [6].
Result
The result of this project was a low-cost prototype that allows us to capture the free energy found in the environment and transform it into useful energy to power other electronic devices. Figure 1 shows the architecture of the device used for energy harvesting, takes advantage of the electromagnetic signals that are captured by an antenna which takes the energy to the electronic prototype where the conversion of rf signals to direct current pulsating CD that is stored in capacitors is carried out to later be used. Table 1 shows that there are 71 antennas located in the different communes of a city in Colombia. Figure 2 shows the electrical circuit of capacitors and diodes that constitute the main elements of the device used for the capture of the energy “energy harvest” that transport the electromagnetic waves of RF that are captured by an antenna, the function of the first condenses.
Figure 3, shows the developed circuit where electronic devices are used, 2 input capacitors to store energy, a circuit of 4 current rectifier diodes, and 2 electrolytic capacitors to store the output energy. Capacitors can vary in value, their value can be about 100 microfarads running at 16 volts, diodes must be of the following nomenclatura 1N34, OA70, 1N4148 low voltage drop.
The circuit serves to take advantage of the energy carried by the RF electromagnetic signals present in the environment and convert them into a useful voltage, we know that we are surrounded by a multitude of electromagnetic waves, there are television, radio, wifi, cell phones, telecommunications antennas, among others and all these signals carry energy which can be converted into electrical energy.
The circuit works by collecting the RF electromagnetic waves through an antenna, the energy of the waves is stored in two input capacitors that after a certain time is discharged through the diode circuit that rectify the current and convert it into pulsating direct current stored in the two output electrolytic capacitors.
The energy stored in electrolytic capacitors is used to activate very low consumption devices, probably an axial pilot, an LED, a clock, a calculator or a sensor.
Conclusion
It can be said that the technological advances that have allowed the construction of many equipment for the emission and capture of rf electromagnetic signals have turned our living space into an ocean through which many radio frequency signals travel simultaneously.
Aware of the above, a prototype of an electronic device was designed and elaborated for the capture of the energy “energy harvest” carried by these RF electromagnetic waves to later take advantage of it for the benefit of humanity in the activation of light signals or very low power devices such as sensors. In addition, the prototype benefits the environment because it is one of the many ways to generate clean energy.
Originality
This work of design and development of the lowcost prototype to store energy was carried out by a community of researchers concerned about contributing to the generation and subsequent use of clean energy in Colombia. The device can be used in places where the energy carried by radio frequency signals is evident.
Limitations
Lack of knowledge about the RF electromagnetic signals emitted and picked up by electrical devices used in the home, in the company, in industry, as well as the little appropriation of the community for their use.
Where:
RF: Radio frequencies.
VHF: Very high frequency.
EMC: Electromagnetic fields.
CD: Direct current. AC: Alternating current.
