Schematic Rise

Saturday, September 6, 2014

Bluetooth Keyboard Controls Dancing Hexapod

Presently, production of robots of different types and functions are rapidly created to help people make their life easier. We can even imagine how the world would look like on the next decade to come. That is – robots do most of the work that people used to do.

Most of the bots in the market are not controlled by Bluetooth except this bot. It’s amazing how this bot dances while controlling the Bluetooth keyboard and a lot of fun to watch for robot fanatics.
In spite the advantages of bots, it can shut down if operation failed therefore failure on its task. Then back to basics must always be a backup.

Friday, September 5, 2014

Schematic diagram of a USB player

Usb series player is an electronic device or electronic circuit that functions as an MP3 player that is stored on a storage device such as USB flash.

In this usb circuit using an IC as a modifier of digital voice data into analog so that it can be applied to a headphone, or again through the power amlplifier strengthened so that it can be heard through the speakers. IC used in this circuit using IC PCM2902 as a modifier of a digital data into analog data storage.

Below is a schematic diagram of a USB player.

Schematic usb player

Touch Switch Using FET

The series of touch this switch be an Touch Switch made using FET. This circuit serves to activate electronic devices only when we touch touch sensors.
Once we release a touch to the sensor, the electronic device that is connected is turned off again. The series of touch switch or touch switch is very simple, composed only of a FET, resistor and capacitor. The series of touch switches / touch switches work with source voltage 12VDC. Detailed series of touch switches / touch switch can be seen in thethe following figure .

FET Touch Switch

The series of touch switches / touch switch can only be used to illuminate DC, 12V DC lamp when it replaced the relay, the circuit can be used safely to load the AC network. Sensor touch to this series was made with 2 pieces of plate are arranged close together (within 1-2mm).

12 V Bidirectional Motor Control Circuit

12 V Bidirectional Motor Control Circuit Diagram diagram. This simple schema drives DC motors with a maximum current of 1 A and can be built with readily available components.The output voltage is adjustable between 0 and 14 V and the polarity can be changed so that not only motor speed but also rotation direction can be adjusted by turning a knob.

The schema is also ideal as a controller for a DC model railway or small low voltage hobby tool. Power for the schema is supplied by a 18 V mains transformer rated at 1.5 A. Diodes D1to D4 rectify the supply and capacitor C1 provides smoothing to give a DC output voltage of around 24 V. A classic ‘H’ bridge configuration is made up with transistors T1/T3 and T2/T4. Transistors T5 and T6 together with resistors R7 and R8 provide the current sense and limiting mechanism. The maximum output current limit can be changed from 1 A by using different value resistors for R7 and R8: IOUT = 0.6 V / R where R gives the value for R7 and R8. For increased current limit the mains transformer and diodes will need to be changed to cope with the extra current as well as the four transistors used in the bridge configuration.

12 V Bidirectional Motor Control Circuit Diagram diagram:

12 V Bidirectional Motor Control Circuit Diagram

Motor speed control and direction is controlled by a twin-ganged linear pot (P1). The two tracks of P1 together with R1/R2 and R3/R4 form two adjustable potential divider networks. Wiring to the track ends are reversed so that as the pot is turned the output voltage of one potential divider increases while the other decreases and vice versa.

In the midway position both dividers are at the same voltage so there is no potential difference and the motor is stationary. As the pot is rotated the potential difference across the motor increases and it runs faster. The voltage drop across D5 and D6 is equal to the forward voltage drop VBE of the bridge transistors and ensures that the motor does not oscillate in the off position with the pot at its mid point.

Mini Bench Supply Wiring diagram Schematic

Every electronics engineer is familiar with the anxiety of the moment when power is first applied to a newly-built schema, wondering whether hours of work are about to be destroyed in a puff of smoke. A high-quality power supply with an adjustable current limit function is an excellent aid to steadying the nerves. Unfortunately power supplies with good regulation performance are expensive and homebrew construction is not always straightforward. Many of the ‘laboratory power supplies’ currently on the market are low-cost units based on switching regulators which, although certainly capable of delivering high currents, have rather poor ripple performance. Large output capacitors (which, in the case of a fault, will discharge into your schema) and voltage over-shoot are other problems.

The power supply described here is a simple unit, easily constructed from standard components. It is only suitable for small loads but otherwise has all the characteristics of its bigger brethren. Between 18 V and 24 V is applied to the input, for example from a laptop power supply. This avoids the need for an expensive transformer and accompanying smoothing. No negative supply is needed, but the output voltage is nevertheless adjustable down to 0 V.

A difficulty in the design of power supplies with current limiting is the shunt resistor needed to measure the output current, normally connected to a differential amplifier. Frequently in simple designs the amplifier is not powered from a regulated supply, which can lead to an unstable current regulation loop. This schema avoids the difficulty by using a low-cost fixed voltage regulator to supply the feedback schema with a stable voltage. This arrangement greatly simplifies current measurement and regulation.

Mini Bench Supply Circuit Diagram

Mini

To generate this intermediate supply volt-age we use an LM7815. Its output passes through R17, which measures the output current, to MOSFET T1 which is driven by the voltage regulation opamp IC1C. Here R11 and C4 determine the bandwidth of the control loop, preventing oscillation at high frequencies. R15 ensures that capacitive loads with low effective resistance do not make the control loop unstable.

The negative feedback of AC components of the current via R12 and C5 makes the schema reliable even with a large capacitor at its output, and negative feedback of the DC component is via the low-pass filter formed by R14 and C6. This ensures that the volt-age drop across R15 is correctly compensated for. C7 at the output provides a low impedance source for high-frequency loads, and R16 provides for the discharge of C17 when the set voltage is reduced with no load attached.

Current regulation is carried out by IC1D. Again to ensure stability, the bandwidth of the feedback loop is restricted by R19 and C8. If the voltage dropped across R17 exceeds the value set by P2, the current limit function comes into action and T2 begins to conduct. This in turn reduces the input voltage to the voltage regulation schema until the desired current is reached. R7, R9 and C3 ensure that current regulation does not lead to output voltage over-shoots and that resonance does not occur with inductive loads.

The controls of the power supply are all voltage-based. This means, for example¸ that P1 and P2 can be replaced by digital-to-analogue converters or digital potentiometers so that the whole unit can be driven by a microcontroller. IC1B acts as a buffer to ensure that the dynamic characteristics of the schema are not affected by the setting of P1. IC1A is used as a comparator whose out-put is used to drive two LEDs that indicate whether the supply is in voltage regulation or current regulation mode. If D2 lights the supply is in constant voltage mode; if D1 lights it is in constant current mode, for example if the output has been short-schemaed. The power supply thus boasts all the features of a top-class bench supply.IC1A and its surrounding schemary can be dispensed with if the mode indication is not wanted.

A type LM324 operational amplifier is suggested as, in contrast to many other similar devices, it operates reliably with input voltages down to 0 V. Other rail-to-rail opamps could equally well be used. The particular n-channel MOSFET devices used are not critical: a BUZ21, IRF540, IRF542 or 2SK1428 could be used for T1, for example, and a BS170 could be used in place of the 2N7002. The capacitors should all be rated for a voltage of 35 V or higher, and R15 and R17 must be at least 0.5 W types. The fixed voltage regulator and T1 must both be equipped with an adequate heatsink. If they are mounted on the same heatsink, they must be isolated from it as the tabs of the two devices are at different potentials.

Author : Alexander Mumm - Copyright : Elektor

Thursday, September 4, 2014

Water level alarm circuit

Here is a simple water level alarm schema that will produce an audible alarm when the water level reaches a preset level.The schema can be powered of a 3V battery and is very handy to use.

The schema is based on an astable multivibrator wired around IC1 (NE 555).The operating frequency of the astable multivibrator here will depend on capacitor C1, resistances R1,R2 and the resistance across the probes A&B.When there is no water up to the probes,they will be open and so the multivibrator will not produce oscillations and the buzzer will not beep.When there is water up to the level of probes,some current will pass through the water,the schema will be closed to some extend,and the IC will start producing oscillations in a frequency proportional to the value of C1,R1,R2 and the resistance of water across the probes.The buzzer will beep to indicate the presence of water up to the level of the sensing probes.

Notes.

* The schema can be powered of a 3V battery.
* Assemble the schema on a good quality PCB or common board.
* The probes can be made of two insulated copper Aluminiun wires.
* Place the probes at the position where you have to sense the leve

230 v Christmas Flash Light

This is Christmas season so you all may get ready to do lots of variations for your house for your gardens.In Christmas Christmas tree gets an important place so I decided to give very important schema to decorate your Christmas tree here these bulbs are blinking.Moving 1M preset the speed of the bulb can be changed.about 20 bulbs (25w) Can be connected for this schema.

Note

# All the resistors must be 1/4w.
# When you work with 230 be careful always try to get the assistance of an elder.

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