This circuit has been configured in Astable mode. The output pulses are determined by the values of resistors R1, R2 and the timing capacitor C1. The formula for the frequency of pulses is: f= 1.44/[(R1+2R2)*C1].
The high and low time of each pulse can also be calculated.
I have written several projects related to LM386 based audio amplifier. LM386 is a versatile…
Here’s a very simple program to display some characters/strings on 16×2 LCD using Nokia N900…
This is a USB or computer powered amplifier with a built-in USB digital audio decoding…
Two digits – Digital object counter DIY kit is one of the most popular kits designed by BuildCircuit. The kit is very popular among electronics beginners and intermediate circuit players.
A single-transistor FM transmitter DIY kit is a simple electronic circuit that allows you to broadcast an audio signal wirelessly using frequency modulation (FM). Such kits are popular among electronics enthusiasts and hobbyists due to their simplicity and educational value. Let’s break down the working of a typical single-transistor FM transmitter: Components: Transistor: The heart…
Remote operated musical bell is one of the interesting experiments every electronics hobbyist would like to make. We have made a very simple remote-operated musical bell DIY kit that requires your half an hour labor to make it work. It uses CD4017 decade counter, UM66 or BT66 musical chip and TSOP4838 infrared sensor as its…
This is yet another FM transmitter DIY kit for beginners and hobbyists. It is slightly different from our previous FM transmitters. It has 3 NPN transistors and the transmission range is around 50-100 meters. It is an enhanced wireless microphone with excellent transmission quality. The voice transmitted by the microphone can be heard using an…
In this tutorial, we will build a thermostat to independently activate and deactivate any domestic device depending on the temperature. We will be able to display the temperature and the activation status of the device connected to the relay on the 16×2 LCD display. Moreover, on the sketch we can modify the temperature, detected by…
This is a simple do-it-yourself (DIY) remote operated switch. You can use this simple kit to turn ON/OFF a pair of LEDs. This has been designed basically as a learning kit. With this kit, you may learn about TSOP4838 infrared sensor and CD4017 versatile IC.
TSIR04 is a USB relay with optically isolated inputs and OLED display and temperature sensor port. It allows computer control switching of external devices by using the USB port of your computer. The communication medium also can be changed easily. Replace the USBBee module with a WiFiBee, it becomes a WIFI relay. It will be a Bluetooth relay when…
This is a project that we have done several times in the past. Serial communication between Arduino and Bluetooth is very easy. There are several apps available online that you can use to control Arduino using smart phone app and also send data from Arduino to your smart phone. In this particular experiment, we will…
Introduction In an era characterized by rapid technological advancements and a growing emphasis on collaboration, open source principles have transcended the realm of software and made an indelible mark on hardware development. Open source hardware (OSH) represents a paradigm shift in innovation, fostering a community-driven approach that democratizes access to technology and enables a more…
Contact-less controlled automatic wardrobe light turns on the LED when you open the wardrobe door. Τhe project is based on Hall effect IC including LED driver and tiny magnet. Board doesn’t require any mechanical switch. When magnet is close to the board, LED is off, when you open the wardrobe door magnet goes far from…
LUX Meter project has been design to measure the illumination. Illumination is luminous flux falling on surface area of photo diode. This illumination converted to corresponding voltage using Op-Amp circuit. SPECIFICATIONS Supply 9 VDC PP3 Battery @ 20 mA  Onboard Photo Diode  Onboard preset for calibration  Range selection via jumper 10mV/LUX, 1mV/LUX, 0.1mV/LUX  Interfacing is…
This project is a sound-activated switch. DESCRIPTION Clap switch/Sound-activated switch designed around op-amp, flip-flop, and popular 555 IC. Switch avoids false triggering by using a 2-clap sound. Clapping sound is received by a microphone, the microphone changes the sound wave to an electrical wave which is further amplified by the op-amp. 555 timer IC acts…
This project is an automatic PIR sensor. DESCRIPTION Project is based on HoltekÂ’s IC HT7610A, which is a CMOS LSI chip designed for use in automatic PIR lamp, flash or buzzer control. It can operate in 3-wire configuration for relay applications. Â In our project we have used relay instead of Traic to connect any kind…
5 LED VU Meter kit is based on LB1409 IC from SANYO, which will indicates the volume level of the audio signal it senses SUPPLY 12V DC @ 50mA PR1 REF SET PR2 AUDIO LEVEL SET SCHEMATIC PARTS PCB DOWNLOADS Audio_VU_Meter.pdf
SCHEMATIC PARTS LIST PCB DOWNLOADS IR_remote_volume_controller.pdf
4 Channel Infrared (IR) Remote controller is using HT12A and HT12D encoder/decoder chips from Holtek. FEATURES Supply – Transmitter : 3 to 5 VDC, 5 V @ 20 mA & Receiver : 5 VDC @ 200 mA Output: 4 channel Latch or Momentary onboard Jumper for selection Crystal based oscillator for the reliability of operation…
