Line Follower ROBOT Controlled by 2051

This Robot use two motors control  rear wheels and the single front wheel is free. It has 4-infrared sensors on the bottom for detect black tracking tape, when the sensors detected black color, output of  comparator, LM324 is low logic and the other the output is high.

Microcontrollor AT89C2051 and H-Bridge driver L293D were used  to control direction and speed of motor.

Fig 1. Circuit diagram of my Robot.

 Fig 2. Circuit diagram of Infrared sensors and comparators.

Read more >>

AC to DC 90 Watt Switching Power Adaptor

AC to DC switching power adaptor circuit with maximum output power of 90W. Switching power supply is built using a high voltage power switching regulator IC MC33374 and some other additional components. The MC33374 IC is a monolithic high voltage power switching regulators that are specially designed to operate directly from a rectified AC line source, and in flyback converter applications.

The MC33374 switching power adaptor combines the required converter functions with a unique programmable state controller. At various variable AC inputs, it is capable of serving up to 6 A current at 15V output voltage. This switching power adaptor is capable of providing an output power in excess of 150W with a fixed AC input of 100V, 115V, or 230V, and in excess of 90 W with a variable AC input that ranges from 85V to 265V.

 

Circuit AC to DC 90 Watt Switching Power Adaptor

Read more >>

Basic Phototransistor Detector

This is a Phototransistor Detector circuit. In this circuit, when the light falling on the phototransistor (Q1) is blocked, its conductance will decrease and the voltage across Q1 will rise. When the voltage rises above 1/2 of the supply voltage the output of the comparator will turn ON and the LED will be lit.

The only critical part of this circuit is the value of resistor R1 which in most cases can be 470K ohms but may have to be increase if the room is dark or decreased if the room is well lit.
Increasing the value of R1 will cause the sensitivity of the sensor to decrease. This may be necessary when the light falling on the cell is not very strong or shadows can affect the phototransistor.
There are a number of phototransistors sizes and case styles. The smaller cases will be easier to hide but connecting wires may be more difficult.

Read more >>

Mobile Phone Charger Circuit For Traveling

Here is an ideal Mobile charger using 1.5 volt pen cells to charge mobile phone while traveling. It can replenish cell phone battery three or four times in places where AC power is not available. Most of the Mobile phone batteries are rated at 3.6 V/500 mA. A single pen torch cell can provide 1.5 volts and 1.5 Amps current. So if four pen cells are connected serially, it will form a battery pack with 6 volt and 1.5 Amps current. When power is applied to the circuit through S1, transistor Q1 conducts and Green LED lights.

When Q1 conducts Q2 also conducts since its base becomes negative. Charging current flows from the collector of Q1. To reduce the charging voltage to 4.7 volts, Zener diode D2 is used. The output gives 20 mA current for slow charging. If more current is required for fast charging, reduce the value of R4 to 47 ohms so that 80 mA current will be available. Output points are used to connect the charger with the mobile phone. Use suitable pins for this and connect with correct polarity. The circuit comes from here.

The Schematic Mobile Phone Charger Circuit For Traveling

Parts:

R1 = 1K
R2 = 470R
R3 = 4.7K
R4 = 270R
R5 = 27R
C1 = 100uF-25V
D1 = Green LED
D2 = 4.7V/1W Zener
B1 = 1.5Vx4 Cells
S1 = On/Off Switch
Q1 = BC548
Q2 = SK100

Read more >>

Printing Compact for Windows Mobile

Today, in turn for the net, I have found a notice interesting. Polaroid, in co

llaboration with Zink Imaging has intention to release to short (the precise date still has not been specified) a new printing for photo super capacities them. The new “Digital Mobile Instant Photo Printer” will be equipped of Bluetooth logo's, in order to allow to print photo from the cellular one and Pocket PC without having to connect some cable, and Pict Bridge USB, compatible with the majority of blots some photographic in commerce. One of the characteristics that they hit more is technology ZINK (Zero Ink Printing Technology) used for the press process. This technology in fact I use not to preview it of cartridges, but the photos come printed publication on a special paper through the stimulation of the present polymers on this last one. The declared dimensions are 120x72x23 millimeter with a weight of 230 grams approximately (Enclosed batteries).

Read more >>

Windows seven WP7 Tips and Tricks - To associate a Bluetooth device

The appointment today with the Guides and Trucchi for Windows Phone 7 is dedicated to the Bluetooth, and in particular to like associating a cap, an earpiece, an external keyboard or any Bluetooth accessory to I telephone Windows Phone 7. First of all we must ignite the Bluetooth.

* From the shielded Start we slide to sinistra per visualizing the directory of the Applications.

*We slide the list and we touch on the Impostazioni.

* We touch the Bluetooth voice and we change the State on Ignited

* In this Windows moment it is already trying the present Bluetooth devices near I telephone. We make sure therefore that our accessory already is ignited.

* Al term of the search we will see a directory with the several names of the found accessories. We touch therefore what we want to install.

* To this point it could be demanded a PIN in order to associate the two devices. Inserted therefore the present code in the handbook of the accessory or a new one and touched on

Read more >>

Digital Remote Thermometer Circuit With Receiver and Transmitter

Remote sensor sends data via mains supply, Temperature range: 00.0 to 99.9 °C

This circuit is intended for precision centigrade temperature measurement, with a transmitter section converting to frequency the sensor's output voltage, which is proportional to the measured temperature. The output frequency bursts are conveyed into the mains supply cables. The receiver section counts the bursts coming from mains supply and shows the counting on three 7-segment LED displays. The least significant digit displays tenths of degree and then a 00.0 to 99.9 °C range is obtained. Transmitter-receiver distance can reach hundred meters, provided both units are connected to the mains supply within the control of the same light-meter.

Transmitter circuit operation:

IC1 is a precision centigrade temperature sensor with a linear output of 10mV/°C driving IC2, a voltage-frequency converter. At its output pin (3), an input of 10mV is converted to 100Hz frequency pulses. Thus, for example, a temperature of 20°C is converted by IC1 to 200mV and then by IC2 to 2KHz. Q1 is the driver of the power output transistor Q2, coupled to the mains supply by L1 and C7, C8.

Circuit diagram:

Transmitter parts:

R1 = 100K 1/4W Resistors
R2 = 47R 1/4W Resistor
R3 = 100K 1/4W Resistors
R4 = 5K 1/2W Trimmer Cermet
R5 = 12K 1/4W Resistor
R6 = 10K 1/4W Resistor
R7 = 6K8 1/4W Resistor
R8 = 1K 1/4W Resistors
R9 = 1K 1/4W Resistors

C1 = 220nF 63V Polyester Capacitor
C2 = 10nF 63V Polyester Capacitor
C3 = 1µF 63V Polyester Capacitor
C4 = 1nF 63V Polyester Capacitors
C5 = 2n2 63V Polyester Capacitor
C6 = 1nF 63V Polyester Capacitors
C7 = 47nF 400V Polyester Capacitors
C8 = 47nF 400V Polyester Capacitors
C9 = 1000µF 25V Electrolytic Capacitor

D1 = 1N4148 75V 150mA Diode
D2 = 1N4002 100V 1A Diodes
D3 = 1N4002 100V 1A Diodes
D4 = 5mm. Red LED

IC1 = LM35 Linear temperature sensor IC
IC2 = LM331 Voltage-frequency converter IC
IC3 = 78L06 6V 100mA Voltage regulator IC

Q1 = BC238 25V 100mA NPN Transistor
Q2 = BD139 80V 1.5A NPN Transistor
T1 = 220V Primary, 12+12V Secondary 3VA Mains transformer
PL = Male Mains plug & cable
L1 = Primary (Connected to Q2 Collector): 100 turns
Secondary: 10 turns
Wire diameter: O.2mm. enameled
Plastic former with ferrite core. Outer diameter: 4mm.

Receiver circuit operation:

The frequency pulses coming from mains supply and safely insulated by C1, C2 & L1 are amplified by Q1; diodes D1 and D2 limiting peaks at its input. Pulses are filtered by C5, squared by IC1B, divided by 10 in IC2B and sent for the final count to the clock input of IC5. IC4 is the time-base generator: it provides reset pulses for IC1B and IC5 and enables latches and gate-time of IC5 at 1Hz frequency. It is driven by a 5Hz square wave obtained from 50Hz mains frequency picked-up from T1 secondary, squared by IC1C and divided by 10 in IC2A. IC5 drives the displays' cathodes via Q2, Q3 & Q4 at a multiplexing rate frequency fixed by C7. It drives also the 3 displays' paralleled anodes via the BCD-to-7 segment decoder IC6. Summing up, input pulses from mains supply at, say, 2KHz frequency, are divided by 10 and displayed as 20.0°C.

Circuit diagram:

Receiver Circuit Diagram

Receiver Parts:

R1 = 100K 1/4W Resistor
R2 = 1K 1/4W Resistor
R3 = 12K 1/4W Resistors
R4 = 12K 1/4W Resistors
R5 = 47K 1/4W Resistor
R6 = 12K 1/4W Resistors
R8 = 12K 1/4W Resistors
R9-R15=470R 1/4W Resistors
R16 = 680R 1/4W Resistor

C1 = 47nF 400V Polyester Capacitors
C2 = 47nF 400V Polyester Capacitors
C3 = 1nF 63V Polyester Capacitors
C4 = 10nF 63V Polyester Capacitor
C7 = 1nF 63V Polyester Capacitors
C5 = 220nF 63V Polyester Capacitors
C6 = 220nF 63V Polyester Capacitors
C8 = 1000µF 25V Electrolytic Capacitor
C9 = 100pF 63V Ceramic Capacitor
C10 = 220nF 63V Polyester Capacitors

D1 = 1N4148 75V 150mA Diodes
D2 = 1N4148 75V 150mA Diodes
D3 = 1N4002 100V 1A Diodes
D4 = 1N4002 100V 1A Diodes
D5 = 1N4148 75V 150mA Diodes
D6 = Common-cathode 7-segment LED mini-displays
D7 = Common-cathode 7-segment LED mini-displays
D8 = Common-cathode 7-segment LED mini-displays

IC1 = 4093 Quad 2 input Schmitt NAND Gate IC
IC2 = 4518 Dual BCD Up-Counter IC
IC3 = 78L12 12V 100mA Voltage regulator IC
IC4 = 4017 Decade Counter with 10 decoded outputs IC
IC5 = 4553 Three-digit BCD Counter IC
IC6 = 4511 BCD-to-7-Segment Latch/Decoder/Driver IC

Q1 = BC239C 25V 100mA NPN Transistor
Q2 = BC327 45V 800mA PNP Transistors
Q3 = BC327 45V 800mA PNP Transistors
Q4 = BC327 45V 800mA PNP Transistors

PL = Male Mains plug & cable
T1 = 220V Primary, 12+12V Secondary 3VA Mains transformer
L1 = Primary (Connected to C1 & C2): 10 turns
Secondary: 100 turns
Wire diameter: O.2mm. enameled
Plastic former with ferrite core. Outer diameter: 4mm.

Notes:

• D6 is the Most Significant Digit and D8 is the Least Significant Digit.
• R16 is connected to the Dot anode of D7 to illuminate permanently the decimal point.
• Set the ferrite cores of both inductors for maximum output (best measured with an oscilloscope, but not critical).
• Set trimmer R4 in the transmitter to obtain a frequency of 5KHz at pin 3 of IC2 with an input of 0.5Vcc at pin 7 (a digital frequency meter is required).
• More simple setup: place a thermometer close to IC1 sensor, then set R4 to obtain the same reading of the thermometer in the receiver's display.
• Keep the sensor (IC1) well away from heating sources (e.g. Mains Transformer T1).
• Linearity is very good.
• Warning! Both circuits are connected to 230Vac mains, then some parts in the circuit boards are subjected to lethal potential! Avoid touching the circuits when plugged and enclose them in plastic boxes.

From Extremecircuit.net

Read more >>

Mobile Phone Charger Circuit For Traveling

Here is an ideal Mobile charger using 1.5 volt pen cells to charge mobile phone while traveling. It can replenish cell phone battery three or four times in places where AC power is not available. Most of the Mobile phone batteries are rated at 3.6 V/500 mA. A single pen torch cell can provide 1.5 volts and 1.5 Amps current. So if four pen cells are connected serially, it will form a battery pack with 6 volt and 1.5 Amps current. When power is applied to the circuit through S1, transistor Q1 conducts and Green LED lights.

When Q1 conducts Q2 also conducts since its base becomes negative. Charging current flows from the collector of Q1. To reduce the charging voltage to 4.7 volts, Zener diode D2 is used. The output gives 20 mA current for slow charging. If more current is required for fast charging, reduce the value of R4 to 47 ohms so that 80 mA current will be available. Output points are used to connect the charger with the mobile phone. Use suitable pins for this and connect with correct polarity. The circuit comes from here.

The Schematic Mobile Phone Charger Circuit For Traveling

Parts:

R1 = 1K
R2 = 470R
R3 = 4.7K
R4 = 270R
R5 = 27R
C1 = 100uF-25V
D1 = Green LED
D2 = 4.7V/1W Zener
B1 = 1.5Vx4 Cells
S1 = On/Off Switch
Q1 = BC548
Q2 = SK100

Read more >>

Motorola CommandOne, an earpiece bluetooth in order to write the SMS

To write SMS while guide is it self most dangerous. In some Countries he is also illegal and in passed they have been also of the serious incidents much for distractions of this type. The keyboards touchscreen, much fashionable ones in the smartphone more recent, than certainly of it do not facilitate the writing. Therefore Motorola it has created the earpiece bluetooth Command One.

Thanks to an application available for Android 2,2 and to the MotoSpeak technology, the customer can dictate the SMS to write and to send it without to watch the screen, simply dictating the commandos you premail. From the point of view hardware the earpiece is large 54 x 18,5 x 11 milimeter and hung 12 grams. The battery allows to an autonomy of 5 hours in conversation or 7 days in standby. In 15 minuteren, moreover, the battery is recharged of 50%. The device available for Will have been born them. Price not communicated.

Read more >>

Simple Car Theft Deterrent

The purpose of this simple circuit is to deter potential car burglars by flashing a few LEDs on a seemingly very sophisticated control panel,implying that the vehicle is equipped with a sophisticated hi-tech alarm system. This simple deterrent is unique in the sense that it is based on just one single uni junction (UJT) and is connected to the car power supply system by just two wires.

The circuit partly relies on it self and partly on the psychological fact that on seeing a brightly lit and active control panel ( even when the car is off ) similar to an alarm system, many thieves, especially the more experienced ones, would don't like to.... to dare to attempt stealing the car at the risk of setting off the alarm.

The circuit as shown in schematic, is based on a UJT type 2N2646, which is wired as a low frequency oscillator. The frequency is determined by the timing  components R1 and C1. Two LEDs are used in flashing mode and two in normal forward conduction pilot mode.R2 and R3 limit the currents passing through the LEDs .       

The circuit Simple Car Theft Deterrent

Read more >>

Headlights On Indicator

Most drivers would have experienced the frustrations at some time or another of parking their car for the day and coming back in the evening only to find that they have accidentally left the head lights on. The result,with the modem small car batteries, quite often is that they have discharged the battery too much to start the engine. And at the end of a long day, the last thing one wants to cope with is a flat and discharged battery.

The basic objective of this low cost monitor is to prevent such (mis) happening from taking place. The circuit sounds an audible alarm as well as flashes a bicolour LED display array at the moment the driver,leaving the headlight on,open his door to leave the car. The alarm does not irritatingly sound every time a co-passenger opens a door. The circuit uses a single CMOS quad NAND gate chip,the ubiquitous 4093.

G1 is wired as a low frequency oscillator which flashes at around 1 Hz. For generating the AC current two 820 ohm resistors have been used rather than the conventional gate.G2 is wired as an AFO which generates the master alarm tone. G3 and G4 are used as buffers which drive the piezo element through the coupling capacitor C3.This piezo speaker has been used in place of normally used buzzers due to its advantages of lower height,lower cost as well as lower current demand.

     

The circuit of headlights on indicator

Diodes D1 and D2 ensure proper operation of the circuit by allowing the alarm to be actived only when the drivers door is opened.The circuit draws negligible current in quienscent state.

Read more >>

The Pocket Receiver

Not that there is any paucity of pocket receivers or that they are too expensive,or that there are hardly any well known circuit that we decided to design' another one'. It's not just another one.

The True Pocket Receiver
 No doubt, dozens of models are commercially available but they aren't truly pocket sized (rather pocket oversized ). Not  many,leave alone the corner of a shirt pocket, fit into a normal shirt pocket leaving enough space to even tack a wallet, Well that's the reason we thought of designing a pocket receiver small enough to fit into a shirt pocket or clip on to a belt that is - a pocket receiver in the true sense. And that exactly is what we have here !


How it Works?
 The circuit is given in picture.It uses an 8-pin DIP ZN415 radio receiver chip from Ferranti. The circuit has an edge over the ZN414 in having an in-built amplifier stage. The IC contains a complete AM detector subsystem. The circuit uses a tuned circuit based on L1 and VC1 serves as tuning control.L1 detects the signals and passe them on to IC1, which in turn, drives high impedance headphones. That's all.

The IC thus allows construction of a light weight,low voltage and quality receiver.

Read more >>