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I came here to show to you
the result
of the project Especial Topics II here on the Federal University of São João del Rei
I have to connect a PIC microcontroller from family 18F
that have native USB support to the computer through this port USB.
And control this car through computer.
How it works:
This first PIC is connect via USB. And from this PIC to this one that is a 18F4550 either,
Through the RS232.
Look that in car's circuit I have the PIC, 2 capacitors, the crystal and a H-bridge.
It is a L293D to control the motor's direction.
A voltage regulator, the LM7805, because the voltage is 12V and I break it into 5V and aplly to the motors.
I could not take the 5V from USB port because I was afraid to burn it with excessive current.
Look that I have only 3 wires arriving into this second board, 2 from power supply and 1 from TX pin.
This side the same components....
And the must have capacitor on pin 18 (USB) of this PIC.
Here I have a red LED to indicate that the PIC is running but was not recognized as a valid device on your computer.
A green LED for when we install the driver, it lights up indicating that the device was enumerated by windows.
And this black ci is a LM35, the temperatur sensor.
The hardware is very simple.
This part is something irrelevant I was doing.
Lets connect it....with this USB cable.
My old computer...... rest in peace.......
The green light is ON, so the circuit is runing.
Lets take a look and see how it has been recognized by windows....
Can you read?...... PIC18.... PicUSB...........
Considering he was recognized, we need an aplication
that controls the car.
Lets open it.
It has be done on the Microsoft Visual Studio C#.
The PIC is connected....
Showing the ambient temperature,
shows on this graph,
Here I have 3 PWM channels by software
I can send to numbers to the PIC, like 5 and 4 and it will returns the sum, 9.
Showing the time and date.....
About the program. Some information....
So, lets test the project, here it goes front, right, back, left and stop.
Let power it and put on the ground.
Lets go, battery is almost dead, but.... lets see what we can do.
Go ahead
Stop
Back
Turn
They are 2 servo's hacked to continuous rotation.
All the controls are on the screen....
Go ahead? ....................... yesssssssssssssss
Thats it.
Ambient temperature is...... 22ºC......
with this sensor. Lets test it. I will put my fingers here and see if it rises.
It is rising....
just a little bit....
and this bar rises together with the temperature until 150ºC. The limit of the LM35.