## 3 Experimental Data and Results
### Utility of Environmental Sensors in Mobile Telephony in the Direct Communication Process
The light intensity thresholds can be seen in Figure 14, which have predetermined values depending on the degree of danger that a certain intensity could constitute. These thresholds are set for the average sensor between 0 and 25,000 lx, compared to the headlight or daylight that falls directly on the  
Figure 13: The structure of events for extracting binary characteristics from light intensity. photoreceptor. After prioritizing these features, the application modulates and decodes the messages, as long as they exist, so that it is not a pedestrian safety zone. Measurements at a distance of up to 10 m in ideal conditions offer a viable perspective in the use of pedestrian and road safety applications using proximity sensors or ambient light. If even in a controlled environment a BER rate of 0% can be achieved, this aspect is no longer in the foreground at a traffic light intersection and on the main road, in which case the use of the OCC application applies. We cannot discuss these transfer speeds being extremely low compared to data transmission via ASCII maps as the purpose of the study was to detect instances dangerous for pedestrians based on the variation of external light near pedestrian crossings. There are times when changing the angle and position of the smartphone amplifies or obstructs communication directly, which is explained by the flat surface of the receiving area that does not have a gradual FOV and can result in angles of 30\({}^{\circ}\)-45\({}^{\circ}\)-90\({}^{\circ}\) in some cases of total efficiency. In the measurements performed in the laboratory, different angles were experimented with, and it was observed that the flat surface of an LED is 100 mm and was exposed in different poses, obtaining for the angle of 90\({}^{\circ}\) a brightness level of approximately 800 lux for bit 0 and 1700 lux for bit 1. Depending on how the position of the smartphone changes from 30 to 35\({}^{\circ}\) or 40\({}^{\circ}\) with a constant distance from the LED, the incidence level of the brightness decreases drastically. Thus, for bit 0, a value of about 200 lux was returned, and for bit 1, the approximate value averaged around 500 lux. In addition, in the internal measurements, the aspects regarding the transfer rates in the case of light are highlighted, which are negligible by the technique presented. The ASCII modulation technique that can transmit characters in binary codes 0 and 1 is extremely vulnerable. Frequency-shift keying (FSK) modulation transmits digital data in different frequency configurations of carrier signals. This modulation is extremely useful in the transmission of urgent messages and in the case of radio broadcasting, where it is necessary to transmit data as quickly as possible. Using ArduinoDroid, convertible iterations were created for the serial data of the  
Figure 14: Structure of light intensity processing ambient sensor and setting safety thresholds. light signals, which change depending on the value received. The secondary algorithm modulates the hash mapping data that come from the brightness of the LEDs and parses each ASCII character. This algorithm uses a different method for each level of intensity in about 255 sections. We must keep in mind that many of the measurements made by the research groups were obtained by configuring the LEDs with FSK modulation, and thus the receiver records the preset and initialized values of the ambient light sensor. Thus, each flash is detected and the light intensity values are automatically analyzed according to the configured luxury value range, displaying only the associated ASCII characters. We need to keep in mind that data transmission without delay sacrifices the attenuation factor and the transfer rate. If the change in brightness frequency is not possible then the ambient light sensor will not be able to detect the intensity nor will it have the desired efficiency in terms of the effect of dimming and scattering the light.