This tachometer lets you measure heartbeats, respiratory rates, and other low-frequency events that recur at intervals of 0.33 to 40.96 seconds. The circuit senses the period offm, computes the equivalent pulses per minute, and updates the LCD accordingly.....

When the time delay expires, SCRl conducts and removes the gate signal from SCR2, which stops the motor. Both the time delay and motor speed are adjustable by potentiometers R2 and R3. If heavier motor loads are anticipated, use the larger C30B SCR in place....

See (a) for the timing information for the alarm circuit in (b). When leaving your vehicle, flip the arming switch and close the door to arm the device. Subsequent opening of an entrance triggers both timers. After the expiration of the entry delay timer,....

Infrared reflective burglar alarm, infrared detection using reflective components (maximum detection range of up to 12m) to trigger the alarm, when Pirates of the situation is detected, an alarm will sound realistic barking to alert the owner of..

This project displays how the Nokia 3310 LCD can be interfaced and driven using the PIC16F628 microcontroller. The code is written in Hi-Tech C and the character table is embeded in the source code. The Nokia LCD has 84x48 pixels and is divided to operate in....

Just 4 integrated circuits and an handful of passive components: the circuit of the Witnesscam is simple. The AVR ATmega32 does an excellent job here. Add the JPG camera module, a PIR sensor and a spare SD-card and you`re done!..

This circuit features automatic Exit/Entry delays, timed Bell Cut-off and System Reset. It has provision for normally-open and normally-closed switches and will accommodate the usual input devices (Pressure Mats, Magnetic Reed contacts, Foil Tape, PIRs and....

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The design came from the interest of finding a new technique of analog to digital conversion. The two types of ADC (Analog to Digital Converter) that inspired me in the development of this circuit are Flash Type ADC and Successive Approximation Type ADC. The....

The USB Performance monitor is a PIC18F2550 based device which shows the performance of your computer using two analogue meters and a RGB LED. The design is based around a stock Hi-Fi VU-meter which is controlled using PWM from the PIC18F microcontroller.....

Designing a controller PCB for a 10x10 white LED matrix clock (inspired by the tutorial here ). It`s based off an ATmega328 AVR IC and Maxim DS3234 SPI RTC. However, I`m stuck: I have no idea how to control my custom non-standard 10x10 LED matrix. Originally....

*We were inspired by the following project, and looked at the code for it, but ended up developing our own. However, if you are interested in making an umbrella that plays musical notes due to press, this is a great page: For more information about the 4051....

This past summer I saw Transformers: Revenge of the Fallen and I was inspired to build an enclosure for a vacuum tube amplifier that incorporated the Decepticon logo. The tube amplifier replaces a solid-state amplifier which was driven by a tube....

Fresnel lens a thin disc of glass or plastic carrying a series of concentric stepped rings, each successive step from the central ring having the surface curvature of a much thicker lens Fresnel lens Fresnel Lenses for Rear Projection Systems, Film Fresnel....

Here is one simple circuit of a general-purpose white LED security light with Passive Infrared (PIR) Motion sensing mechanism. At the heart of the circuit is a PIR sensor module SB0061. SB0061 is a pyroelectric sensor module which developed for human body....

Metal detector using avr tiny13. i m planning to use 555 ic to energize the coil and giving this output to tiny13 at pin2(clk1). i metal detector using 555 (9) dark sensor circuit diagram (8) 555 dark detector circuit (8) pir detector circuit diagram (7)....

I was inspired by the excellent work done by others on these boards using DMX sequencing and various parallax products to interface with them. I decided to take my crack at it using the propeller only with a slightly different spin, pun intended. I decided....

The circuit features automatic Exit and Entry delays, timed Bell Cut-off and System Reset. It has provision for normally-open and normally-closed switches and will suit the usual input devices (Pressure Mats, Magnetic Reed contacts, Foil Tape, PIRs and....

This is a two-zone alarm - with automatic exit, entry and siren cut-off timers. It can be triggered by the usual types of normally-closed input devices - such as magnetic reed contacts - foil tape - PIRs etc. I`ve used a 12-volt supply in the diagram - but....

The following circuit shows about PIR Motion Sensor Circuit Diagram. Features: simple and high efficiency, operational amplifiers a sound ....

The circuit features automatic Exit and Entry delays, timed Bell Cut-off and System Reset. It has provision for normally-open and normally-closed switches and will suit the usual input devices (Pressure Mats, Magnetic Reed contacts, Foil Tape, PIRs and....

The GLMDPCB motion detector board is a double sided etched, screened and drilled printed circuit board designed for the GLMDA motion detector circuit shown in the schematic below. All or part of the circuit can be built. For some robotic and other special....

Well this is a Very Accurate LC Meter based on PIC 16F628A. Having inspired from surprisingly accurate LC Meter. This is my attempt to build an accurate L/C meter. This design is little different from other designs found on the internet. The goal of my hard....

The following circuit shows about 12V PIR Sensor Timer Circuit Diagram. Features: 12 Volt DC, will turn on a floodlight or other device for a time ....

The head will be powered by servomotors and will be built from sheet plastic, metal or plywood. The template which can be used for cutting sheet material can be found at the end of this article. Download the template, compare the size of the printed....

A low power fm pirate radio. The output power is around +35 dBm ( 3. 16 watts) over 50 ohms load and +24 volts power supply. The project consists in a hartley oscillator ( modulated VCO), and tree stages ( Class A, common emitter) of RF amplifiers. The first....

Voicemail capacility (although not implemented, there are four ADCs that can be used to sample and record the phone audio) A storage volume (SD card) would need to be connected. This project was inspired by these other homemade exchanges: Markus Wandel and....

You can add as many extra zones as you like to the Transistor Burglar Alarm System. The first circuit is designed to be used with the usual types of normally-closed input devices such as - magnetic-reed contacts - micro switches - foil tape - and PIRs. The....

A motion detection alarm circuit using a PIR.SENSOR motion detection, if the move is a positive light from the PIR sensor, triggered by a delay circuit, Q1 and....

A video of my friend James playing his electric guitar, patched through the audio echo effect system, and then to his amp. I didnG ‚¬ t make any effort to prove that this isnG ‚¬ t a conspiracy, so youG ‚¬ ll have to take my word that the echo effect is....

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This is a simple transistor-based burglar alarm circuit. Its features include automatic Exit and Entry delays - together with a timed Bell cut-off and Reset. It`s designed to be used with the usual types of normally-closed input devices such as -....