Generative Art Conference GA2006

The purpose of this project is to study the environmental response to human actions. An environment was created with several visible laser beams. If one of these beams is interrupted (for example, if someone crosses it), an alarm will be triggered. Consequently, the space is sensitive to the presence of people. The power source was developed to replace the batteries of the laser beams, which have an autonomy of only a couple of hours, and to supply the trigger circuit. There are two outputs: one is stabilized at 5 V DC with a maximum power of 5 W, designed to power the laser beams. The 7805 voltage regulator is suitable for the laser connections because its output voltage is 5 VDC, while the beams require 4.5 V. The voltage difference will be compensated by inserting a resistor in series with each beam. This experiment will utilize four laser beams, each requiring 4.5 V and 20 mA. According to Ohm's law, the calculations for the resistors can be made accordingly. The alarm circuit includes a Light Dependent Resistor (LDR) that acts as a trigger for the BC327 transistor. When the laser beam is interrupted, the LDR causes the transistor to conduct, energizing the relay. The relay has an electric seal that keeps it energized even if the transistor stops conducting. The siren is connected through the relay to a 12V power source, thus triggering the alarm when activated. The project includes 13 mirrors, each measuring 50x50 mm with a transparency of at least 70%. These mirrors will be mounted on cubical wooden pieces measuring 55x55x20 mm. A 6 mm² hole will be drilled into the side of the wood, parallel to its surface, through which a sturdy 6 mm² cable will be inserted and secured with glue. The support structure will also be made of wood, consisting of a heavy rectangular base (approximately 5 kg). A vertical brown wooden stick will be inserted through a hole in the base. The mirrors will be adjusted by bending and twisting their wires. The laser beams and the LDR sensor will also be connected via this 6 mm² wire to the base. It is essential to prepare the environment to be nearly dark, as the lasers will not be visible otherwise. To enhance the visibility of the laser beams, a glycerin smoke machine can be employed. This installation has been simulated in a CAD system, with some angles rendered to illustrate the environment. An isometric view of the installation is depicted in the provided figure.

The circuit design for this project involves several key components and their interconnections. The power supply circuit is built around the 7805 voltage regulator, which converts a higher input voltage to a stable 5 V DC output. This output is essential for powering the laser beams, which operate at a nominal voltage of 4.5 V. To accommodate this, a series resistor is calculated using Ohm's law to ensure that the current through each laser beam does not exceed 20 mA. The LDR is positioned in the path of the laser beams, and its resistance changes when the beam is interrupted. This change is detected by the BC327 transistor, which acts as a switch. When the LDR's resistance drops due to the interruption, the transistor turns on, allowing current to flow through the relay coil. The relay, once energized, closes its contacts and connects the siren to the 12V power supply, thus sounding the alarm.

The mirrors are strategically placed to reflect the laser beams throughout the environment, creating a network of beams that can detect movement. The mirrors' transparency and positioning are crucial for maximizing the visibility of the beams. The use of a glycerin smoke machine enhances the visibility of the laser rays, making it easier to identify any interruptions. The entire setup is designed to be robust and stable, with the heavy wooden base providing support and minimizing movement. The project aims to create an effective and sensitive detection system that can respond to human presence in a controlled environment.The conception of this project is directed to the study of the environment response due to a human action. Based on that subject, an environment was prepared with several visible rays of laser. If one of theses rays is interrupt (eg. someone crosses it), an alarm will be triggered. Therefore, the space of the environment is sensible to the presenc e of people. The reason to develop the power source is to replace the laser beans batteries - which don`t have autonomy greater than a couple hours - and also to feed the trigger circuit (see circuit diagram on figure 1). There are two different outputs. One output is stabilized, with DC 5 V and 5 W maximum power. It has the purpose to feed the laser beans. The 7805 voltage regulator is the one that best suits to the lasers connections, because it`s voltage output is 5 VDC, while the beans need 4.

5 V. The difference of the voltage will be solved through the insertion of a resistor in series with each bean. This experiment will have 4 laser beans, fed by the 5 V power source. Each laser bean works with a 4. 5 V voltage and 20 mA current. Therefore, using the Ohm`s law, follows: The alarm circuit consists on a LDR sensor (Light Diode Resistor) that operates as a trigger of the BC327 transistor.

If the ray of laser stops falling upon the LDR (eg. a person or an object has crossed the laser ray), it will make the transistor enter on its conducting procedure. If the transistor starts conducting, it will energize the relay. The relay has an electric seal that keeps it energized even if the transistor stops conducting. The siren is connected through the relay to the 12V power source, therefore, if the relay is activated, the alarm is triggered.

The project will have 13 mirrors, with dimensions of 50x50 mm and transparency equal or greater than 70%. They will be attached on 55x55x20 mm cubical pieces of wood. A hole of 6mm2 will transpose the lateral of the wood, in parallel with its surface. Through this hole, it will be stick a piece of cable, very hard and with thickness of 6 mm2. Glue can be used in order to fixate the wire inside the hole. The support can also be made of wood. A rectangular base of heavy wood (about 5 kilos) should be enough. A vertical wood stick made of brown stick can be settled trough a hole on the base. The mirrors adjusts will be made by deforming and twisting their wire. The laser beans and the LDR sensor can also be attached through this 6 mm2 wire to the bases. It is imperative to prepare the room for almost complete darkness, otherwise the lasers won`t be seen.

To provide a carrier in the air that helps to make the rays of laser more visible, a glycerin smoke machine can be used. This installation was simulated in a CAD system, and some angles of it were rendered in order to demonstrate the environment.

On figure 4, there is an isometric view of the installation, made on a square space. 🔗 External reference