Light Sensitive Audio Oscillator


Light Sensitive Audio Oscillator project is a fun loving project which will create different sound effects depending on the light falling on the sensor (LDR).


  • Supply input 5 ~ 12 VDC
  • Output 8 Ohms, 0.5 W Speaker
  • Terminal pins for supply voltage and speaker connection
  • Power-On LED indicator
  • PCB dimensions 38 mm x 44 mm

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Water Level Sensor Alarm


This small water sensor alarm circuit makes a loud warning sound when a water  sensor detects a quantity of water.


  •  Input : 9 VDC @ 40 mA
  •  Output : Buzzer
  •  Berg connector for voltage supply input
  •  Power-On LED indicator
  •  Four mounting holes of 3.2 mm each
  •  PCB dimensions 35 mm x 32 mm


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Dark Sensitive Switch Circuit Based on Single Transistor


Dark Sensitive switch project based on single BC547 transistor, Relay operates when light that falls on the LDR, goes below a set point. It’s very simple and low cost dark sensitive switch required few components.


  • Input : 12 VDC @ 55 mA
  •  Relay output : NC – C – NO
  •  Onboard preset to set the level
  •  Power-On LED indicator
  •  Relay On LED indicator
  •  Screw terminal connector for easy relay output connection
  •  Four mounting holes of 3.2 mm each
  •  PCB dimensions 44 mm x 40 mm


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TB6600 Based 4.5A Bipolar Stepper Motor Driver


Bipolar stepper drive board described here has been designed around TB6600HG IC. The TB6600HG is PWM chopper type single chip bipolar sinusoidal micro-step stepping driver. Maximum  Load 4.5A, Supply 10V to 42V DC.



  •     Based on Single chip and Second chip for auto half current control
  •     Suitable for Nema17, Nema23, Nema34 bipolar stepper motors
  •     Suitable for 4Wires, 6 wires and 8 wires stepper motor.
  •     Forward and reverse rotations available
  •     Selectable Phase (Micro-step) drives 1/1, 1/2, 1/4, 1/8, and 1/16
  •     Maximum Input supply 42V DC Minimum Input supply 10V DC
  •     Output current 4.5Amps
  •     Output Fault Monitor LED indicator
  •     On Board Power LED indicator
  •     On Board step pulse input indicator
  •     Standby auto half current reduction circuitry onboard
  •     Built in Thermal shutdown (IC)
  •     Built in under voltage lock out (UVLO) circuit (IC)
  •     Built in over current detection (ISD) circuit (IC)
  •     Large capacitor to handle inrush current




  •     Robotics
  •     Large format Size Printers
  •     CNC
  •     Routers
  •     3D Printers
  •     Machine Automations
  •     Camera Pan Tilt Heads
  •     Slot Machine
  •     Vending Machine


Heat-sink and Thermal Shutdown

The board has current  sense resistors and these resistors has been set as per maximum load current 4.5A, If you use lower current motor, please set the PR1-Preset ( Potentiometer) to the required  level for the motor. At maximum current load TB6600 IC will overheat in some time and a RED LED turns on. This LED goes off once the temperature falls to a safe operating level.


Micro Stepping

A 4way DIP switch is used to set the micro step modes (Full, Half, Eight, Sixteenth), please see the table for Micro step settings. DIP Switch settings should be changed when power is off so the correct selection is active at power up.


Step Pulse

Minimum positive duty cycle of the input step pulse should be 2.2us and required 5V (TTL) signal. A positive going pulse on the step input activates a step operation.


Current Settings

Average drive current can be set using a Preset (On Board PR1 Potentiometer). CN7 (CT) onboard connector   is provided  to measure the voltage to set the motor current (torque). Voltage range to set the torque   0.3V to 3.5V



Never connect or remove supply wires, motor wires, or input interface when power is on, this can cause damage to drive.

Switch Off the Power to set the Micro stepping

Before using this drive, please have proper information about stepper motors, Motor impedance, Inductance and other specs.



All Inputs are optically isolated to prevent the device for any kind of noise, short circuits.


 Enable: Required 5V DC input, Set high Input disabled the drive, Set low input Enable the drive

Dir.: Required 5V DC input, Set high Input CW Rotation, Set low input CCW Rotation, Direction of the motor depends how stepper motor has been wired.

CLK: Step Pulse required 5V DC TTL pulse



4 Wires, 6 Wires, 8 Wires Motors can be used with this drive in bipolar mode.On board LED for Alert



SW4 (LATCH): ON=Automatic Return if Thermal Shutdown Or Over Current Detection OCCURS

SW4 (LATCH) : OFF= On Fault condition required power on/off


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5V/1A (700mA) Regulated Power Supply LM7805, CA7805


This project will provide 5 V @ 700 Amp DC Regulated Supply.  The project is based on the Lm7805 voltage regulator in TO220

  • Input 7 – 15 VAC
  • Output 5 V @ 1 A peak (700 mA ideal) regulated low ripple DC voltage
  • Onboard bridge rectifier to convert AC to DC
  • Thermal overload/short circuit protection (provided by IC feature)
  • Screw terminal connector for easy input and output connection
  • Filter capacitors for low ripple DC output
  • LED indication for output
  • Four mounting holes of 3.2 mm each
  • PCB dimensions 35 mm x 45 mm









Dual Adjustable Power Supply +/- 1.2V to 30V DC. 1.5Amp

Dual Adjustable Power Supply (1)

This project is a solution to power up most of devices or projects required dual (+/-) adjustable power supply. The circuit is based on LM317 positive and LM337 negative voltage regulator. LM317  series of adjustable 3 terminal regulator is capable of supplying in excess of 1.5A over a  1.2V to 30V DC output range, due to TO3 package of  IC and large heat sink the power supply can handle maximum load  current.

  • Output: +/- 1.2 to 30V DC
  • Output Current: 1.5Amps
  • Supply Input: 24V-0-24V AC, 2Amps Center tape Transformer
  • CN1: Transformer Connections
  • CN3: +/- Dual Supply Outputs
  • P1: Positive Voltage Adjust
  • P2: Negative Voltage Adjust
  • D1: Positive Power Indicator
  • D2: Negative Power Indicator



Dual Adjustable Power Supply (2)


Dual Adjustable Power Supply (3)


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Dual Adjustable Power Supply (4)


Electronic Toggle Switch


The Project works as electronic toggle switch. The circuit is based on CMOS CD4013 Flip Flop IC,

The circuit has two stable states, ON and OFF. Once it is ON, it remains ON till you press the switch again. A short button press of a tactile switch SW1 latches the circuit ON and another toggles it back OFF.

Relay switch contacts can handle high AC Voltage as well as High DC current, this makes the project suitable for application like ON/OFF Fan, Light, TV, Pump, DC Motor, any electronic project required electronic toggle operations and few other devices work on AC voltage up to 250V AC or DC current up to 5Amps.



TV, Audio Equipment’s, Radio, Fan, Pump, DC Motor, Electronic Projects ON/OFF


  • Supply: 12V DC
  • Current: 60mA
  • D1: Power Indicator
  • D3: Toggle State ON or OFF indicators
  • CN1: Supply Input
  • SW1: Toggle Operation


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Long Duration Timer


This timer project can be used to switched ON/OFF any device after set time, this circuit can be used in lots of application like  switched ON/OFF Radio, TV, Fan, Pump, kitchen timer, the circuit describe here its unique in its own. Project has been designed around two CMOS IC CD4001 and CD4020.  Two gates of CD4001 make the oscillator and rest has been configured as flip-flop, BC547 transistor is to drive the Relay. Circuit is pretty simple, has jumpers to set the required time duration, Preset is to set the 1Hz oscillator. SW1 is to start the timer, SW2 Power on/off project. Relay output switch contacts can handle 230V AC @ 5Amps

  • Supply: 12V DC
  • Current Consumption: 60mA
  • D3: Power Indicator
  • D2: Timer Operation Indicator
  • CN2: Supply Input
  • J1-J7: Time Set (Please see Schematic for Time Duration)
  • CN1: Relay Switch Connection Normally Open or Normally Closed
  • SW1: Timer Start
  • SW2: Timer Supply On/Off
  • PR1: 1Hz Frequency Set


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32 Seconds Voice Record Playback Circuit


Project   has been designed around Win bond’s ISD1616 IC (SMD) IC, which is fully integrated, single-chip, single massage voice record and playback device ideally project suited to a variety of electronics systems. Massages are stored in flash memories made in unique Multilevel Storage Technology (MLS). Therefore, voice or audio data are stored directly into the memory in their natural form without any compressions alike digital approach, providing high-quality, solid-state audio reproduction. Project provides high quality audio recording and simple operations.  Massage duration is user selectable in ranges from 10 to 20 Seconds depending on the sampling rates from 4 KHz to 12 KHz adjustable via on board potentiometer (preset), giving the users greater flexibility in duration versus recording quality. Massage recording and playback is easy using on board tact switches. This project can be used in variety of application like, Interactive Games and booths, Light and  sound shows, gaming machines, toys, robots, animatronics, lifts/escalators, warning systems, security systems, audio guide, home appliances. Project work on 5V DC @ 100mA. It consumes minimal current in standby mode typical 1uA to 100ua (Without power LED). The device enters into standby mode automatically once an operation is completed for power saving purposes.



  • Toys
  • Amusement Equipment’s
  • Interactive Games
  • Lifts/Escalators
  • Warning Systems
  • Security Systems
  • Audio Guide
  • Home Appliances
  • Robotics
  • Animatronics
  • Light and Sound Show



  • Power supply input 5 VDC @ 100 mA
  • Power supply spans a range from 2.4 to 5.5 VDC
  • Standby current 1 uA typical and 10 uA maximum without power LED
  • IC Enters in standby mode immediately after record playback cycle
  • Microphone preamplifier with automatic gain control built in IC
  • PWM Class D speaker driver
  • Direct Drive Speaker 8 Ohms or typical buzzer
  • AUD current output to drive external power transistor
  • Onboard microphone
  • Easy operation via onboard tact switches
  • Onboard tact switches for Level trigger Play, Edge trigger Play, and Recording
  • Onboard power indication
  • Onboard preset for sampling rates settings
  • Onboard recording indication
  • Supply input and speaker terminal via header connector
  • Low Noise high quality voice record/playback
  • 100 Year massage retention
  • 100,000 record cycles
  • Speaker is not provided with kit


Testing the Project,

Connect the 8 ohms 0.5W speaker to LS1 (SPK), apply 5V DC to CN1, and make sure polarity is correct otherwise it can damage the IC. CN2 (AUD) is current drive output to connect the project with external audio amplifier.

Record A Message

The device starts recording whenever REC switch pressed or recording pin of IC pulled HIGH to LOW and stays at LOW. Recording stops when the recording switch released or the signal on ICs pin returns to HIGH.  The device starts recording from the beginning of the memory when REC transits from HIGH to LOW and stays at LOW. A record cycle is completed when REC is pulled to HIGH or entire memory is filled up. Then an End-of-Message (EOM) marker is written at the end of message, enabling a subsequent Playback cycle to terminate appropriately. Hence, the device automatically enters into standby mode. REC takes precedence over any playback operations. If REC is pulled LOW during a playback cycle, the playback immediately halts and recording starts from the beginning of the memory. The REC pin has an internal pull-up device


Playing the recorded message

Edge-trigger Playback: A playback operation starts when switch (SW2) PLAYE pressed or PLAYE pin of IC detects a LOW going signal exceeding the specified denounced time

Level-trigger Playback: A playback operation begins when switch (SW3) PLAYL is pressed and playback stops when switch is released. PLAYL pin of the IC detects a LOW going signal and remains at LOW. Playback stops when the signal returns to HIGH


The ISD1616 IC provides record/playback duration from 10.6 seconds to 32 seconds. Sampling rate and duration are determined by on board 220K Ohms PR1 potentiometer connected to the Rosc pin.


Sample Rate Rosc. PR1 Potentiometer Duration
12Khz 60K Ohms 10.6 Seconds
8Khz 80K Ohms 16 Seconds
6.4Khz 100K Ohms 20 Seconds
5.3Khz 120K Ohms 24 Seconds
4Khz 160K Ohms 32 Seconds


D1 (Green LED)

The D1 Green LED goes on during recording, the output pin of IC provides an active-LOW signal during recording, which is used to turn on a D1 (Green LED) as a “record-in-progress” indicator. However, during playback, the D1 LED blinks a few times per second to indicate a “playback-in-progress” operation. It returns to an OFF state when operation stops.



D2 work as power indicator, it is in on state during power is on.

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Classic Timer Based On 555 Timer

Classic AC 230 V Timer project can be used in all application requiring a timer of up-to 3 Minutes to operate or control any AC mains load of up-to 200 Watts.  This project is based on the Classic 555 Timer IC, triggering a TRIAC.  Input and Output is Optically Isolated.

  •  Supply input 12 VDC
  •  Mains supply input 240 VAC or 120 VAC ( Read Note for 120V/230V AC)
  •  Output: up-to 200 Watt
  •  Optically isolated Input / Output
  •  Onboard start and reset tactile switch
  •  Timer On LED
  •  Preset adjustable and jumper selectable for range
  •  Power-On LED indicator
  •  Screw terminal connector for easy mains supply input and load connection
  •  Four mounting holes of 3.2 mm each
  •  PCB dimensions 46 mm x 91 mm










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