10 LED VU Meter Using IC LM3914

This 10 LED VU meter circuit has only a few parts but is useful as an indicator for the measurement of entering acoustic signals. The circuit is a perfect one chip replacement for the standard analog meters. It is completely solid state and will never wear out

LM3914 VU Meter Circuit

The circuit is built around an LM3914 IC. The input signal from the VU meter is put on pin 5 of IC1. Through pin 9 of IC1 is the display mode sets (bar or dot instructions). In the drawn state IC1 works in the dot mode. When pin 9 is coupled to pin 3, the IC works in bar mode. Obviously the whole circuit consumes less power in dot mode.

List Component

C1        : 2.2uF/ 25V Electrolytic Capacitor
R1        : 1K  Resistor
D1        : 1N4002 Diode
LED1-LED  : 10 x  LED or LED Array
U1        : LM3915 

Notes

• V+ can be anywhere from 3V to 20V. 
• The input is designed for standard audio line voltage with has a maximum input voltage of 1.3V.
• Pin 9 can be disconnected from ground to make the circuit use a moving dot display instead of a bar graph display.

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AT89s51-52 and AVR USB Downloader

Microcontroller T89s51, AT89S52 and AVR is an idol among students. Well now because of technology trends and laptop PCs already left the LPT and COM so more and more difficult to download the firmware into the microcontroller, via LPT or COM. Solutions to be overcome with AT89S S-series, because the facility program downloads with the ISP (MISO, MOSI, SCK, RST), then use the ISP downloader which is also commonly used for this AVR microcontroller type. Time to play man with AT89s so much easier via USB without hassle and unplug the IC.

AT89s51-52 and AVR
USB Downloader Circuit

After you finish creating the PCB from the circuit above, then fill it to the ATmega8 with firmware usb51.hex do not forget to set low fuse = EF (SUT0 = 0, others = 1) and high fuse = C9 (SPIEN = 0, CKOPT = 0, BOOTSZ1 = 0, BOOTSZ0 = 0, others = 1). Of course, charging into the ATmega8, firmware downloader tool is needed.

For those who need a filling firmware and more complete information about the USB Downloader please visit http://guru.technosains.com/

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Rangkaian Pendeteksi Angin

This circuit uses an incandescent lamp to detect airflow (mendeteksi angin). With the filament exposed to air, a constant current source is used to slightly heat the filament. As it is heated, the resistance increases. As air flows over the filament it cools down, thus lowering it's resistance. A comparator is used to detect this difference and light an LED. With a few changes, the circuit can be connected to a meter or ADC to provide an estimation on the amount of air flow. 

Rangkaian Pendeteksi Angin

LM339 Pinout

The glass will have to be removed from L1 without breaking the filament. Wrap the glass in masking tape and it in a vise. Slowly crank down until the glass breaks, then remove the bulb and carefully peel back the tape. If the filament has broken, you will need another lamp.

List Component

R1   : 100 Ohm 1/4W Resistor 
R2   : 470 Ohm 1/4W Resistor 
R3   : 10k 1/4W Resistor 
R4   : 100K 1/4W Resistor 
R5   : 1K 1/4W Resistor 
C1   : 47uF Electrolytic Capacitor 
U1   : 78L05 Voltage Regulator 
U2   : LM339 Op Amp 
L1   : #47 Incandescent lamp with glass removed (See "Notes") 
D1   : LED 

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Stepper Motor Controller using IC 4027

The stepper controller circuit is very interesting, since most lines the step motor controllers are very expensive. The circuit is made ​​of standard components and can easily be adjusted by a computer. If you cheap surplus transistors and stepper motors, the price of the circuit can be less than $ 15.

Stepper Motor Controller Circuit using IC 4027

This stepper controller circuit shown here can used to control the unipolar stepper motor, the which has four coils. The stepper controller circuit can drive for a motor current of up to about 500 MAMP / Winding by Suitable heat sinks for the SL-100 In higher currents seem 2N3055 power transistors can be used as darlington pair along with the SL-100. All diodes are used to protect the transistor from back current transients.

List Componet

R1, R2 ,R3, R4: 1K 1/4W Resistor
D1, D2, D3, D4: 1N4002 Silicon Diode
Q1, Q2, Q3, Q4: TIP31 NPN Transistor (See Notes) TIP41, 2N3055
U1            : 4070 CMOS XOR
U2            : 4027 CMOS JK Flip-Flop
S1            : SPDT Switch

Notes: 
1. You should be able to substitute any standard (2N3055, etc.) power transistor for Q1-Q4.
2. Every time the STEP line is pulsed, the motor moves one step.
3. S1 changes the motors direction.

4027 CMOS JK Flip-Flop IC  Pinout

4070 CMOS XOR IC Pinout

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Ukuran Box Subwoofer 10"

This subwoofer box was created to match and aid the 1.618 Hi-Vi 3-way tower loudspeakers. The main focus of the HiVi 10" subwoofer was to reproduce ultra low frequencies that the 1.618 could not reproduce and aid in overall low end musical reproduction. Low, flat and not "boomy" was priority one. This subwoofer project uses the 10" subwoofer driver which can deliver plenty of bottom end.

The enclosure design and model frequency response are shown below.


Note:

• 10" 4 ohm subwoofer
• O-Audio 500 Watt plate amplifier
• Freq Response: 25Hz up to chosen x-over point.
• Overall Dimension: 21"x 12.75"x 20"

For more details on how to make it please read more http://diyaudioprojects.com/Speakers/HiVi-DIY-Subwoofer/

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4,8W Class-A MOSFET Amplifier

This is very simple Class-A 2SK1058 MOSFET Amplifier circuit. It is easy to build it, Must use supply volte 24V at high current. It produces the most purest sound. I have no idea of distortion levels etc. but it has a very fine grain, and delicately textured quality.

Skema Rangkaian 4,8W Class-A MOSFET Amplifier

This is one package 2SK1058 N-Channel MOSFET Pin Diagram

The four resistors are 15ohm and 10W each the which I wired two in series for 30 ohms and then the two sets of 30 ohms are wired in parallel to give a total resistance of 15 ohms. These get extremely hot and burn about 30W at idle.


For more detail please read more http://diyaudioprojects.com/Solid/ZCA/ZCA.htm

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