Nowadays we can not get through without our phones. And everyone has faced the situation when our battery runs down in the most inappropriate moment. Of course, you can charge it in a public place. But it is very daugerous to leave your device without control for a long time. We thought about it and tried to solve this problem.
Step 1: Our Idea
We decided to create a box with 4 drawers in which you can charge the phone. The user must place his magnetic card to RFID - reader, which will open one of the free drawers. After closing the drawer, you leave your device in safety, because noone else but you can open the drawer. Get your device back if you place one more time the magnetic card.
Step 2: Installation
To implement our ideas we used:
Operational Amplifiers lm358
Сharge cable USB 4 in 1
Step 3: Assembly
connected to arduino in the following sequence:
MFRC522 Arduino Mega
Step 4: Assembly
Servo the cells connected to 5 volts, the control wires to the terminals 8, 9, 10 and 11.
Arduino Micro servo
5V * Red(Центральный)
GND Черный или Коричневый (Левый)
pin 8,9,10,11 Белый или Оранжевый (Правый)
Step 5: Assembly
End stop for determining the closed state of the cell to connect from 4 to 7 Arduino pin with pull-up resistor of 10 ohms to GND, the other output to 5 volts
Step 6: Assembly
To determine the charging current junction following scheme at operational amplifier LM358. Such schemes require 4 us for each cell.
Step 7: Body
We cut out the body on the laser machine, after making drawings CorelDraw. So we made a 3D model.
We used plywood 8mm and 4mm.