[en] This Final Degree Project proposes the design, simulation and prototyping of a system equipped with solar energy, capable of reading a micro SD card and playing an audio file. The aim of this system is to place it in any outdoor space to help visually impaired people to identify what is in front of them. A photovoltaic plate will convert solar energy into electricity, which will be stored in a battery. For this process, it is necessary to adapt the voltage of the solar cells to the voltage of the battery, reducing it from 6 V to 4.2 V by means of a buck circuit designed for this purpose. In this same circuit, the voltage reaching the battery will be regulated by adjusting the duty cycle of a PWM signal generated by the ATMega328-U microcontroller. In addition, the microcontroller will manage the communication with the micro SD card to read and play the audio file. Both the microcontroller and the micro SD card will be powered at 5 V by an MT3608 boost converter. To ensure adequate loudness, an audio amplification circuit has been added to the system. A simulation of the different components mentioned has been carried out using Proteus 8 software, and the characteristics of various signals have been analysed through their graphs. After ensuring correct operation, assembly was carried out on a printed circuit PCB to reduce the size of the system. A protective case was also designed and printed with a 3D printer. The challenges and decisions taken during the development of the project are detailed in this technical report. An analysis of the results obtained has also been carried out, from which conclusions are drawn and presented at the end of the work.

[eu] Gradu Amaierako Lan honetan eguzki energiaz horniturik, mikro SD txartel bat irakurri eta audio artxibo bat erreproduzitzen duen sistema baten diseinua, simulazioa eta prototipaketa proposatzen da. Sortutako sistema, edozein aire zabaleko eremutan koka zatekeen eta ezgaitasun bisuala daukaten pertsonei aurrean daukatena azaltzea du helburu. Plaka fotovoltaiko batek eguzki-energia eraldatu eta sortutako elektrizitatea bateria batean gordeko du. Prozesu hau burutzeko, eguzki zelulen tentsioa bateriaren tentsiora egokitu behar da, hau da 6 V-tik 4,2 V-ra jaitsi behar da, eta horretarako buck zirkuitu bat diseinatu da. Zirkuitu berean, bateriara heltzen den tentsioa ATMega328-U mikrokontrolagailuak sortzen duen PWM seinale baten lan-zikloa aldatuz erregulatuko da. Horrez gain, mikrokontrolagailuak mikro SD txartel batekin komunikazioa bete behar du audio artxiboa irakurtzeko eta erreproduzitzeko. Azken bi hauek boost motako MT3608 bihurgailu baten bitartez 5 V-ra elikatuko dira. Soinua behar bezain ozen entzuteko, sistemari anplifikazio zirkuitu bat gehitu zaio. Aipatutako atal ezberdinen simulazioa, Proteus 8 softwarean burutu da, eta horien grafikoen bidez hainbat seinaleen ezaugarriak aztertu dira. Funtzionamendu egokia bermatu ostean, tamaina murrizteko asmoz, muntaia PCB zirkuitu inprimatuan gauzatu da. Horrez gain, sistema osoa babesteko karkasa bat diseinatu eta 3D inprimagailu bidez inprimatu da. Lanaren garapenean izandako oztopoak eta hartutako erabakiak memoria tekniko honetan biltzen dira. Aldi berean, lortutako emaitzen azterketa burutu da eta hauekin, lanaren bukaeran ondorioak ateratzen dira.