What Must todo

This universal battery charger is based on LM317 and has an adjustable regulated output voltage and also has an adjustable constant-current charging circuit that makes it suitable to use for charging most NiCad batteries and some other types of batteries . This LM317 universal battery charger can charge a single cell or a number of series-connected cells up to a maximum voltage of 18 V.

This universal battery charger circuit use just some common electronic components like LM317 regulator , operational amplifier and some 2n3055 power transistors .2n3055 power transistors Q1 and Q2 are connected as series regulators to control the battery chargers out¬put voltage and charge-current rate. The LM317 used as an adjustable voltage regulator supplies the drive signal to the bases of power transistors Q1 and Q2.



By turning the potentiometer R9 the output-voltage level will be modified. A current-sampling resistor, R8 (a 0.1-fi, 5-W unit), connected between the negative output lead and circuit ground.As the charging voltage across the battery begins to drop, the current through R8 decreases , then the voltage feeding pin 5 of U3 decreases, and the comparator output follows, turning Q3 back off, which completes the signals circular path to regulate the batterys charging current. The charging current can be set by adjusting R10 for the desired current.

Motor Drive On Line Follower Robot - To move the Line Follower 2 options can be used, namely motor or DC motor servo motor. If you want to use a DC motor, it must use a DC motor is mounted gear system (geared motors DC).Kind of like it is still difficult to find in the market, so the choice often falls to the servo motor.Another advantage of the servo motor is a servo motor can be controlled directly from the microcontroller PIC16F84 with no extra-Driver IC again.

Wheel Drive On Line Follower Robot - Wheels are used in line follower may vary - kinds, ranging from the brand, type, dimensions, and so forth. Line Follower Robot are generally categorized based on the number of wheels it has.Starting from the robot with two wheels, three wheels or four wheels. But that is commonly used is a robot with three or four wheels.

Placed behind a pair of wheels connected by two motors each - each have an independent pace.It is important that the robot can turn left and to right and set the desired rotation rounds. While the front wheels could use a caster wheel that serves as a buffer. Many brands of caster wheels that can be used, one of the most famous is from the manufacturer Tamiya. However, no cane akarpun so - if we want a cheaper and sometimes free, odor-preventing former rodadeodorant can used as a caster wheel.

In the Line Follower Robot Microcontroller Many types of microcontrollers that can be used in line follower robot, some examples include AT89C2051 (8051 Core), AT89C51 (8051 Core), ATmega8 (AVR Core), ATmega16 (AVR Core) and many more.

In the microcontroller, the program will be included so that the robot can adjust the rotation speed of each motor and able to perform the desired movement. Because the line follower robot speed is high enough, then some of the control algorithm needs to be applied to a robot capable of running smoothly. Control that can be a continuous control, PID, fuzzy logic, or the other.

Speed setting is important, especially when faced with change of trajectory, from a straight trajectory to bend or otherwise of the bend to the straight path. Just as when the robot moves fast and then find a corner, then the robot would be bounced. That requires a series of dynamic motor speed control depending on the type of trajectory is traversed. If the robot goes straight, the speed of the robot cultivated at a maximum. If the condition of the bend, then the speed is reduced depends on the sharpness of the bend. In essence, the speed of the robot is made flexible according to the situation on the ground. On the robot, the speed reduction can be done using the PWM (Pulse widht Modulation) controller, namely the reduction of speed by reducing the current to the motor.

These metal detector circuit diagram is based on the TDA0161 monolithic integrated circuit , designed for metallic body detection by detecting the variations in high frequency Eddy current losses. For detecting metals , TDA0161 require an external LC tuned circuit .

Metal Detector Circuit diagram

Output signal is determined by supply current changes. Independent of supply voltage, this current is high or low according to the presence or the absence of a close metallic object. This metal detector circuit use two LEDs , which offer an visual indication of presence or absence at a metals ,around the coil . To adjust the circuit you need to make sure there is no metal near the coil and then set the fine adjustment to a "Mid position". After that you need to adjust the course adjustment to turn on the LED and , adjust the fine adjustment to turn off the LED.

This detector electronic circuit operates over a wide range input voltage of 4 -35 volts .  If you want you can use other values for the Cx capacitor and for L1 inductor  ( changing this value will affect the frequency oscillation and the detection range ) .

A small 325mW amplifier with a voltage gain of 200 that can be used as a bench amplifier, signal tracer or used to amplify the output from personal radios, etc.

 Circuit Diagram


Notes:
The circuit is based on the National Semiconductor LM386 amplifier. In the diagram above, the LM386 forms a complete non-inverting amplifier with voltage gain of x200.

A datasheet in PDF format can be downloaded from the National Semiconductor. The IC is available in an 8 pin DIL package and several versions are available; the LM386N-1 which has 325mW output into an 8 ohm load, the Lm386N-3 which has 700mW output and the LM386N-4 which offers 1000mW output. all versions work in this circuit.

The gain of the Lm386 can be controlled by the capacitor across pins 1 and 8. With the 10u cap shown above, voltage gain is 200, omitting this capacitor and the gain of the amplifier is 20.

The IC works from 4 to 12Volts DC, 12Volt being the maximum recommended value. The internal input impedance of the amplifier is 50K, this is shunted with a 22k log potentiometer so input impedance in this circuit will be lower at about 15k. The input is DC coupled so care must be taken not to amplify any DC from the preceeding circuit, otherwise the loudspeaker may be damaged. A coupling capacitor may included in series with the 22k control to prevent this from happening.

The Finished Circuit.