Solar Operated Car

Solar Operated Car

This project controls a remote robot through RF. The ordinary 433mhz RF modules are used in this project. AT89C2051 microcontroller is used in this project. It is also an 8051 microcontroller. You can burn the same hex file into any 8051 microcontroller.
You can make the robot to move front and back, turn left and right. Also you can control the speed of the robot from the remote. The PWM technique is used for obtaining the speed control of the motor.

Car is a miniature prototype car powered by batteries whose various movements can be control either manually or automatically, or the combination of both. Here the command is given through keyboard; it would have been better if we used IR remote control or something of that kind rather than using keyboard for commanding.

Motor:

We are using a 5V dc motor to drive the vehicle. The speed of the vehicle and its strength is controlled by the proper use of pulley. The rear wheel of the vehicle is connected to this motor through a pulley. This motor is meant for moving the vehicle both in forward and backward direction. Microcontroller (8051) controls the forward and backward movement of the vehicle in the following manner:

Circuit diagram of Motor connection

Here in the above circuit, T1, T2, T3, T4 are the NPN power transistor (2N3055). A0, A1, A2, A3 are the signals coming from the micro controller. With the specific combination of A0, A1, A2, A3 we can change the direction of rotation of motor as follows:

Case I:When A0=high; A3=high; & A1=low; A2=low
The motor rotates in clockwise direction
Case II:When A0=low; A3=low; & A1=high; A2=high
The motor rotates in anti-clockwise direction
Case III:When A0=low; A3=low; A1=low; A2=low
The motor stops the rotation.

Stepper Motor:

A 5V dc Stepper motor is fixed at the front wheel lever directly. It enables the vehicle to rotate left or right through any angle. The electrical pulses generated from the micro controller directly control the movement of the stepper motor.

A stepper motor is an electromagnetic device that translates electrical pulses into mechanical movement.

Circuit diagram of stepper motor interfacing is shown bellow. First 4 pins port 2 is connected to motor. Power transistors must be connected to drive the motor.

Interfacing stepper motor to 8951

Transmitter and Receiver:

We are fitting three IR sensors along with the transmitter at the front of the vehicle in such an angle that the sensor will detect the signal only if certain obstacle is placed at the front of the vehicle at a distance of around 3 inches. This range of detection can be further adjusted by adjusting the amplitude of transmitter or by adjusting the angle of alignment between the transmitter and the sensor. All these sensors work independently and can sense the obstacle that comes at the front of the vehicle through different position independently. Thus with these three sensors, we are able to cover the entire frontal view of the vehicle at a distance of 3 inches. The circuit diagram of the transmitter and the receiver are given below:

Transmitter:

Transmitter circuit is used to transmit the IR rays. The IR LED emit infrared light switch is put on in the transmitting unit. To generate IR signal 555 IC based astable multivibrator is used. Infrared LED is driven through transistor BC 177.

Circuit diagram of IR Transmitter

Receiver:

The receiving unit consists of a sensor and its associated circuitry, which detects IR pulses transmitted by IR-LED. As a result the monostable is triggered and a short pulse is applied to port 2.5 of 8951. Circuit diagram is shown below. Do the same circuit two more times and connect it into 6 and 7 of port 2.

Circuit diagram of IR Receiver

Working:

Manual mode:

In manual mode, the vehicle can be commanded through a wireless microphone to

1.  Turn left.

2.  Turn right.

3.  Stop.

4.  About turn.

5.  Park left.

6.  Park right.

1. Turn left:

On getting the command of turn left, the vehicle turns towards left with 30 degree and after 3sec; it comes back to the original position. The degree in which the vehicle rotates, and the timing of coming back to the original position can be further adjusted based on our desired.

2. Turn right:

Right turn is same as that of left turn except for the fact that on getting command it turns towards right. All the modifications those are valid for the left turn is also true in this case.

3. Stop:

Once the vehicle gets the command for “stop” it remains in the idle state. There after its control is hand over to the beginning state.

4. About turn:

In about turn, the vehicle turns backward in two steps same as we did in our normal car. In first step the vehicle move only 90 degree and repeat the same in second step.

5. Park left:

On getting the command to park left, the vehicle parks on the left side of the road in a single step.

6. Park right:

Park right is same as that of park left, but here in this case, it parks towards the right side of the road.

You can also add two modes to the present design using two more switches. They are

Auto Mode:

In auto mode, the vehicle can be programmed to move at a particular place and park there. While moving, if any obstacle comes at the front of the vehicle, it will deviate its path automatically and come to the original path. The place where the vehicle is desired to move is the choice of the user; it can be either straight or bent path.

In our model, we have put three sensors at the front of the vehicle, so it is up to the user that, by what angle the vehicle should deviate. Further, it can be programmed on which side it should deviate, either left or right based on our desired. To alert the user that the vehicle is deviating an obstacle, a musical sound system is fitted in the vehicle, so that whenever it is deviating any obstacle, it will also play a music simultaneously.

Hybrid Mode:

It is the combination of both auto and manual mode. Here the vehicle can be commanded to move, to turn left or right. Further, while moving, if any obstacle comes on its path, it will deviate and come to its original path after deviating. However, if so happen that before coming to the original path, the sensor detects another obstacle; it will halt the movement of the vehicle, and play an alarm music as long as the obstacle is detected. The moment second obstacle is removed; the vehicle will continue its earlier execution.

Such dangerous job could be done using small spy robo all the developed and advance nations are in the process of making combat robo design, a robo who can fight against enemy. Our robo us just a step towards similar activity.

This robo is radio operated , self powered , and has all the controls like a normal car. A laser gun has been installed on it so that it can fire on enemy remotely when required, this is not possible until a wireless camera is installed. Wireless camera will send real time video and audio signals which could be seen on a remote monitor and action can be taken accordingly. Being in size small, will not be tracked by enemy on his radar. It can silently enter into enemy canopy or tent and send us all the information through its’ tiny camera eyes. It can also be used for suicide attack, if required.

Heart of our robo is intel’most power family of microcontroller 8051,we are using at89c2051 Two microcontrollers ic2 is first microcontroller which acts as master controller ,decodes all the commands received from the transmitter and give commands to slave microcontroller ic3. Slave microcontroller is responsible for executing all the commands received from the master and also generating pwm pulses for the speed control . Ic4 is ld293 motor driver ic which drives two nos motors m1 and m2.
Two no bumper switch are added bmp 1 and bmp2 so that in case of accident our battery dose not drains out. both the motors will stop instantly and after few swcond robo will move in opposite direction take turn to left or right direction and stops and stop .
Circuit operation:

RF433-RX is 433mhz radio receiver which receives the transmitted coded from the remote place these codes are converted to digital format and out put is available to the pin no 2 of the ic2 master microcontroller, this is the rx pin of inbuilt uart of the microcontroller. We are using uart to receive our codes at 1200 boud rate.. Based on the input codes master will give command to slave microcontroller and robo will behave as follows.

a. moves in forward direction
b. moves in reverse direction,
c. speed controls in both the direction
d. it can even turn left or right while moving forward or in reverse direction.
e. Instent reverse or forward running without stopping
f. In case of bump,moves reverse turn left or right and wail for the next instruction .
g. On the spot left or right turn to pass through the nerrow space
h. We have also added head light, back light.and turing lights to left a right .

These lights automatically comes on while robo is in movement. Laser gun can be fired at any time irrespective of robo stopped or moving. Bmp1 and bmp2 (forward and fterward)bumpers are connected to pin no 6 of the ic2 when ever this pin becomes low robo will stop instantly and will move few steps in reverse direction turn left or right and stops.

Pin no 11,12,13,15.16 and 17 of the master microcontroller are connected to the slave microcontroller ic3 to give the following pulses to the slave microcontroller
1.Start/stop
2. Increase speed
3. Increase speed
4. Direction change
5. Turn left

6. Turn right
Slave microcontroller ic3 pins 15,16,17,18,19 are connected to ic4 motor driver ic, pin17 of the slave gives the pulse width modulation pulse which is connected to pin 1 and 9 of ic4 this is en pin of ic 4
Pin 18 and 19 controlls one motor m1 and pin 15 and 16 of the slave controller controls the m2 motor.

Note : Solar Charging Using Microcontroller – Part of this ckt will be used in the solar Car This circuit will be added with the – IR sensor for Guiding , and Motor Driver and the Buzzer.

The circuit of the solar charge controller is shown in Fig. 1. It comprises microcontroller AT89C2051, serialanalogue-to-digital converter ADC0831, optocoupler MCT2E, regulator 7805, MOSFETs BS170 and IRF540N,transistor BC547, LCD and a few discrete components. Component description is given below.

Microcontroller.Microcontroller AT89C2051 is the heart of the circuit. It is a low-voltage, high-performance,8-bit microcontroller that features 2 kB of Flash, 128 bytes of RAM, 15 input/output (I/O) lines, two 16-bittimers/counters, a five-vector two-level interrupt architecture, a full-duplex serial port, a precision analogue comparator,on-chip oscillator and clock circuitry. A 12MHz crystal is used for providing the basic clock frequency.All I/O pins are reset to ‘1’ as soon as RST pin goes high. Holding RST pin high for two machine cycles, whilethe oscillator is running, resets the device. Power-on reset is derived from resistor R1 and capacitor C4. SwitchS2 is used for manual reset.
Serial ADC. The microcontroller monitors the battery voltage with the help of an analogue-to-digitalconverter. The ADC0831 is an 8-bit successive approximation analogue-to-digital converter with a serial I/Oand very low conversion time of typically 32 μs. The differential analogue voltage input allows increase of thecommon-mode rejectionand offsetting of the analoguezero input voltage. Inaddition, the voltage referenceinput can be adjustedto allow encoding of anysmaller analogue voltagespan to the full eight bitsof resolution. It is availablein an 8-pin PDIP packageand can be interfaced to themicrocontroller with onlythree wires.
LCD module.The systemstatus and battery voltageare displayed on anLCD based on HD44780controller. The backlightfeature of the LCD makesit readable even in low lightconditions. The LCD isused here in 4-bit mode tosave the microcontroller’sport pins. Usually the 8-bitmode of interfacing witha microcontroller requireseleven pins, but in 4-bitmode the LCD can beinterfaced to the microcontrollerusing only sevenpins.
Solar panel.The solarpanel used here is meant tocharge a 12V battery andthe wattage can range from10 to 40 watts. The peak unloaded voltage output of the solar panel will be around 19 volts. Higher-wattage panelscan be used with some modifications to the controller unit.
Rechargeable battery.The solar energy is converted into electrical energy and stored in a 12V lead-acid battery.The ampere-hour capacity ranges from 5 Ah to 100 Ah.
Dusk-to-dawn sensor.Normally, in a solar-photovoltaic-based installation—for example, solar home lightingsystem, solar lantern or solar streetlight—the load (the light) is switched on at dusk (evening) and switched offat dawn (morning). During daytime, the load is disconnected from the battery and the battery is recharged withcurrent from the solar panel. The microcontroller needs to know the presence of the solar panel voltage to decidewhether the load is to be connected to or disconnected from the battery, or whether the battery should be in chargingmode or discharging mode. A simple sensor circuit is built using a potential divider formed around resistorsR8 and R9, zener diode ZD1 and transistor T1 for the presence of panel voltage.
Charge control.Relay RL1 connects the solar panel to the battery through diode D1. Under normal conditions,it allows the charging current from the panel to flow into the battery. When the battery is at full charge(14.0V), the charging current becomes ‘pulsed.’ To keep the overall current consumption of the solar controllerlow, normally-closed (N/C) contacts of the relay are used and the relay is normally in de-energised state.
Load control.One terminal of the load is connected to the battery through fuse F1 and another terminal of the load to an n-channel power MOSFET T3. MOFETs are voltage-driven devices that require virtually no drivecurrent. The load current should be limited to 10A. One additional MOSFET is connected in parallel for morethan 10A load current.