Quadrature Encoder to Clock and Direction Signal Converter Using LS7084/LS7184

The quadrature LS7084/LS7184 Module is a CMOS quadrature clock converter. Quadrature clocks derived from optical or magnetic encoders, when applied to the A and B inputs of the LS7084 are converted to strings of a Clock and an Up/down direction control. These outputs can be interfaced directly with standard Up/Down counters for direction and position sensing of the encoder.

J1 Jumper input selects between x1 and x4 modes of operation. A high level selects x4 mode and a low-level selects the x1 mode. In x4 mode, an output pulse is generated for every transition at either A or B input. In x1 mode, an output pulse is generated in one combined A/B input cycle.

Resistor R7-RBIAS (Pin 1) Input for external component connection. A resistor connected between this input and VSS adjusts the output clock pulse width (Tow). For proper operation, the output clock pulse width must be less than or equal to the A, B pulse separation (TOW £ TPS).



  • Supply 5V DC
  • +4.5V to +10V operation (VDD – VSS)
  • On Board Power LED
  • J1 Encoder pulse multiplication ( Jumper JL Close =1X, Jumper JH Close = X4)
  • Header Connector for Encoder Interface
  • X1 and X4 mode selection
  • Programmable output clock pulse width
  • On-chip filtering of inputs for optical or magnetic encoder applications.
  • TTL and CMOS compatible I/Os
  • Up to 16MHz output clock frequency


Note : Circuit uses LS7084 IC , which is CMOS IC and working voltage range 4.5V to 10V and it has two scale up  range.X1 and X4. The board can be used with LS7184 which can work with lower supply range 3.3V to 5V and it can provide X1,X2,X4 resolution, refer data sheet of LS7184 for more information.








Note: Check Graph for R7- Bias Selection





What is Quadrature Encoder?

The most common type of incremental encoder uses two output channels (A and B) to sense position. Using two code tracks with sectors positioned 90 degrees out of phase, the two output channels of the quadrature encoder indicate both position and direction of rotation. If A leads B, for example, the disk is rotating in a clockwise direction. If B leads A, then the disk is rotating in a counter-clockwise direction.

By monitoring both the number of pulses and the relative phase of signals A and B, you can track both the position and direction of rotation.

Some quadrature encoders also include a third output channel, called a zero or index or reference signal, which supplies a single pulse per revolution. This single pulse is used for precise determination of a reference position.

How Quadrature Encoder Works?

The code disk inside a quadrature encoder contains two tracks usually denoted Channel A and Channel B. These tracks or channels are coded ninety electrical degrees out of phase, as indicated in the image below, and this is the key design element that will provide the quadrature encoder its functionality. In applications where direction sensing is required, a controller can determine direction of movement based on the phase relationship between Channels A and B. As illustrated in the figure below, when the quadrature encoder is rotating in a clockwise direction its signal will show Channel A leading Channel B, and the reverse will happen when the quadrature encoder rotates counterclockwise.

Apart from direction, position can also be monitored with a quadrature encoder by producing another signal known as the “marker”, “index” or “Z channel”. This Z signal, produced once per complete revolution of the quadrature encoder, is often used to locate a specific position during a 360° revolution.

Constant Current Laser Diode Driver Using OPA2350 OP-AMP

The voltage-controlled current source circuit can be used to drive a constant current into a signal or pump laser diode. This simple linear driver provides a cleaner drive current into a laser diode than switching PWM drivers. The basic circuit is that of a Howland current pump with a current booster (Q1) on the output of a R-R CMOS OPA2350 op amp (U1). Laser diode current is sensed by differentially measuring the voltage drop across a shunt resistor (RSHUNT) in series with the laser diode. The output current is controlled by the input voltage (VIN) that comes from Trim pot PR1.


  • Supply 3,3V DC
  • Load Up to 300mA
  • PR1 Trimpot Current Adjust



Download Data Sheet OPA2350




4 Channels Optically Isolated I/O Board Using 6N137 Optocoupler

4 Channel Opto isolated board has been designed around 6N137 Opto-coupler, the 6N137 optocoupler is designed for use in high-speed digital interfacing applications that require high-voltage isolation between the input and output. Applications include line receivers, microprocessors or computer interface, digital programming of floating power supplies, motors, and other control systems.

The 6N137 high-speed optocoupler consists of a GaAsP light-emitting diode and an integrated light detector composed of a photodiode, a high-gain amplifier, and a Schottky-clamped open-collector output transistor. An input diode forward current of 5 milliamperes will switch the output transistor low, providing an on-state drive current of 13 milliamperes (eight 1.6-milliampere TTL loads).

Note : For 3.3 Input Signal R1, R4, R7, R10 = 220E


  • Supply 5V DC
  • Input Signal : 5V DC TTL
  • Header Connectors for Inputs & Outputs
  • D1 Power LED





40Pin/28Pin dS PIC Development/Evaluation Board

The ds PIC Development Board is a development and evaluation tool that helps create embedded applications using dsPIC30F Digital Signal Controllers for motor control family. Sockets are provided for 28 and 40-pin devices in the motor control family.

The dsPIC Development has been designed mainly for Motor dsPIC30F4011 Digital Signal Controller in the 40-pin motor control socket and dsPIC30F4012 28 Pin digital signal controller, the board can also be used with other ds PIC ICs. Board provided with 3.3V and 5V regulator, crystal oscillators, a programming   connector. In addition, the board is populated with dual header connector for all I/O ,reverse supply protection diode, onboard 3.3V & 5V LED , Screw terminal for supply input, push button switch for reset, 6 pin header connector for programming, serial communication  header connector, jumpers for multi serial communication option , electrolytic capacitor for filters. Optional provision for LM317T  TO220 Regulator for 3.3V and 5V and Jumper for 3.3V or 5V power supply selection to power up the dsPIC.

  • Dual sockets for  28 and 40-pin PDIP  devices
  • On Board Reverse Supply Input Socket
  • Supply Input 7V to 15V ( LM7805 & LM1117-3.3V) Regulators
  • Optional Supply Input 7V to 36V DC If Populate LM317T TO220 IC
  • Sample application programs and project files available from microchip
  • website  for supported dsPIC30F devices
  • dsPIC30F4011 40-pin PDIP and dsPIC30F4012 28-pin PDIP
  • On Board Dual 5V & 3.3V regulator provided to full fill low and
  • TTL supply requirement.
  • On Board programming Header Connector
  • On Board 3.3V & 5V Power LED
  • Jumper to select 3.3V or 5V going to dsPIC
  • Jumper for 2 UART Port or CAN selection
  • Controller Area Network (CAN) interface
  • 1 push button for Reset
  • Access to all pins on the dsPIC30F device sockets via Dual  headers










Tiny Metronome Using 555 Timer and Buzzer

A metronome is a device that produces an audible click  sound at a regular interval that can be set by the Trimmer Potentiometer , typically in beats per minute (BPM). Musicians use the device to practice playing to a regular pulse.

Musicians practice with metronomes to improve their timing, especially the ability to stick to a tempo. Metronome practice helps internalize a clear sense of timing and tempo. Composers often use a metronome as a standard tempo reference—and may play or sing their work to the metronome to derive beats per minute if they want to indicate that in a composition.

555 Timer IC is a heart of the project, Buzzer used as sound generator, Trimmer Potentiometer provided to set the tempo of sound. circuit works with wide range 5V to 12V and its consumes 30-50mA current. Frequency range adjustable 1Hz to 20Hz. other frequency output possible altering the C3 and PR1.






About 555 Timer

These devices are precision timing circuits capable of producing accurate time delays or oscillation. In the time-delay or mono-stable mode of operation, the timed interval is controlled by a single external resistor and capacitor network. In the a-stable mode of operation, the frequency and duty cycle can be controlled independently with two external resistors and a single external capacitor.

The threshold and trigger levels normally are two-thirds and one-third, respectively, of VCC. These levels can be altered by use of the control-voltage terminal. When the trigger input falls below the trigger level, the flip-flop is set, and the output goes high. If the trigger input is above the trigger level and the threshold input is above the threshold level, the flip-flop is reset and the output is low. The reset (RESET) input can override all other inputs and can be used to initiate a new timing cycle. When RESET goes low, the flip-flop is reset, and the output goes low. When the output is low, a low-impedance path is provided between discharge (DISCH) and ground.

The output circuit is capable of sinking or sourcing current up to 200 mA. Operation is specified for supplies of 5 V to 15 V. With a 5-V supply, output levels are compatible with TTL inputs.


Multiple-Message Record/Playback Module Using ISD1932/ISD1964

This Module has been designed around Nuvoton’s ISD1932 ChipCorder® is the newest single-chip multiple-message record/playback series with dual operating modes (address trigger and direct trigger) and wider operating voltage ranging from 2.4V to 5.5V. The sampling frequency can be selected from 4 to 12 kHz via an external resistor, which also determines the duration from 10.6 to 32 seconds. These ICs are designed mostly for standalone applications, and of course, it can be used in conjunction with a microcontroller, if necessary.


The two operating modes are address trigger and direct trigger. While in address trigger mode, both record and playback operations are manipulated according to the start address and end address specified through the start address and end address pins. However, in direct trigger mode, the device can configure the memory up to as many as eight equal messages, pending upon the fixed message configuration settings. With the record or playback feature being pre-selected, each message can be randomly accessed via its message control pin.

The device has a selectable differential microphone input with AGC feature or single-ended analog input, analog in, under feed-through mode. Its differential Class D PWM speaker driver can directly drive a typical speaker or buzzer.


Sampling Rate or Recording Time Selection

  • R5: 53.3K 12 KHz sampling frequency 21.3 Seconds Voice Recording
  • R5: 80K    8 KHz sampling frequency 32 Seconds Voice Recording
  • R5: 100K 6.4 KHz sampling frequency 40 Seconds Voice Recording
  • R5: 120K 5.3 KHz sampling frequency 48 Seconds Voice Recording
  • R5: 160   4 KHz sampling frequency 64 Seconds Voice Recording



  • Wider operating voltage from 2.4 to 5.5V
  • Higher sampling frequency from 4kHz to 12kHz
  • Voice Recording Time 21 Seconds to 64 Seconds depend on sampling rate selection ( R5-OSC Resistor )
  • FT: converts MIC+ to ANAIN & feeds it to the speakers
  • R/P: record/playback switch
  • REC: level or edge recording
  • PLAYE: edge-trigger, toggle on/off
  • PLAYL: level playback or looping playback
  • LED: LED output for recording
  • LED Blinks for while at end of the message in play mode
  • NORM (Address Trigger) : variable message duration
  • MODE: (Direct Trigger) : fixed message duration









Example Circuit for Multiple switch connections


LED Based Strobe Controller with Frequency Control and Display Using PIC16F1825 and CAT4016 IC

Strobe provides regular flashes of light. Usually Strobes are designed using Xenon Tubes, Here is LED based simple solution can be used as strobe for entertainment and events and also as warning signals, Project is based on PIC16F1825 micro-controller with two digit frequency display.CAT4016 IC provided to drive 2 display.

Project provides TTL output signal, frequency 1Hz-25Hz, Tact switches provided to set the frequency.  Use solid state relay , BJT transistor or Mosfet at output to drive LED, choose right load driver as per LED required current.


The CAT4016 is a 16 channel constant current driver for LED billboard and other general display applications. LED channel currents are programmed together via an external RSET resistor. Low output voltage operation on the LED channels as low as 0.4 V (for 2 to 100 mA LED current) allows for more power efficient designs.

A high-speed 4-wire serial interface of up to 25 MHz clock frequency controls each individual channel using a shift register and latch configuration. A serial output data pin (SOUT) allows multiple devices to be cascaded and programmed via one serial interface. The device also includes a blanking control pin (BLANK) that can be used to disable all channels independently of the interface.

Thermal shutdown protection is incorporated in the device to disable the LED outputs if the die temperature exceeds a set limit.


  • Supply 4.5 to 5V DC
  • Frequency 1Hz To 25Hz
  • Easy Interface with Relay Board
  • Easy Interface with Solid State Relay
  • On Board Power LED
  • On Board Output LED
  • Onboard Switch to set the frequency
  • 2X7 Segment 0.5 Inch Display

Note: Refer Our DC Solid State Relay Circuit  which can be used to drive LED or any other Load.


  • Strobe for Entertainment
  • Traffic Signal
  • Warning Signal
  • Ambulance Warning Signals
















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