This is a new design for a universal gear indicator that can be fitted to any motorcycle as an aftermarket accessory. Its main advantage is that its operation depends entirely on the gear shift lever movement, instead of connecting to speedometer and....

In the circuit of Figure 1, assume that a brush-type dc motor must drive a load back and forth between two endpoints on a lead screw. Optical sensors determine end of travel, and an SPDT switch selects to which end to send the load. The sensors themselves....

This is a very simple to implement Temperature Sensor. It uses LM35DT as a semiconductor temperature sensor which operates with a +5 volt DC. It produces an analog output voltage, proportional to the change in surrounding temperature in Celsius scale....

This circuit functions with inaudible (ultrasonic) sound. Sound of frequency up to 20 kHz is audible to human beings. The sound of frequency above 20 kHz is called ultrasonic sound. The circuit described generates (transmits) ultrasonic sound of frequency....

Wine doesn`t like subzero temperatures, and during wintertime, my "winecellar" got pretty cold. There was an electric heating element, but the thermostat was broken, so it was either full burn or nothing. That`s how the temperature monitor/controller came to....

The signal emitted by an IR remote control contains two parts, the control pulses and a modulated carrier wave. The control pulses are used to modulate the carrier, a popular modulation frequency being 36 and 42KHz. The signal is radiated by an IR diode,....

Using ac-line power sources and batteries for remote humidity sensors is undesirable because these sources can be troublesome if you mount them in inaccessible points, such as smokestacks, cold-storage chambers, or darkrooms, where maintenance is difficult....

This electronic lock can be used with any type of iButtons you may already have, since the only thing needed is the internal serial number, that's different for every iButton. The command used to read the serial number is the same for all iButtons. The....

A strap-down inertial-navigation system uses silicon sensors to measure displacement without entailing the bulk and expense of moving parts or GPS receivers. For example, a three-axis accelerometer and three angular-rate sensors can determine the position....

The MPF102 (Q1) can be replaced with a NTE451 or ECG451, but still widely available. JFET-N-CHAN, UHF/VHF AMP. The 2N3565 (Q1/Q2) can be replace with a 2N2222(A), BC107, BC108, BC109(A/B/C), NTE123A, or ECG123A. The TIP31 (Q3) can be replaced with a NTE196....

Using this low-cost project one can reproduce audio from TV without disturbing others. It does not use any wire connection between TV and headphones. In place of a pair of wires, it uses invisible infrared light to transmit audio signals from TV to....

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 such as Foil Tape, Pressure Mats, Magnetic Reed Contacts,....

The original application for the circuit in Figure 1 was to check the number of revolutions of an engine with only one LED as an indicator. The measurement of the number of revolutions usually involves sensors with a frequency output proportional to the....

The present document shows step by step how to easily build an interesting pointing device: the wireless tilt mouse, that allows to control the mouse?s cursor on the PC screen through the tilt of the board itself. The analog data from a 3-D accelerometer and....

Using this low cost Project one can reproduce AUDIO from TV without disturbing anyone. It does not use any wire between TV and HEADPHONE. In place of pair of wires it uses invisible Infrared light to transmit audio signals from TV to Headphone. Without using....

This Project Line Following Autonomous Robot is based on 8 bit Microcontroller AT89C2051. This Robot follows the black line which is drawn over the white surface or it follows the white line which is drawn over the black surface. The infrared sensors are....

Catalytic bead sensors are used primarily to detect combustible gases. They have been in use for more than 50 years. Initially, these sensors were used for monitoring gas in coal mines, where they replaced canaries that had been used for a long period of time...

The circuit described here is that of a metal detector. The opera- tion of the circuit is based on superheterodyning principle which is commonly used in superhet receivers. The circuit utilises two RF oscillators. The frequencies of both oscillators are....

This 1-Wire MicroLAN [1] uses a capacitor and diode half-wave rectifier to provide parasitic power from the data line for the station's various sensors and to transfer data (see Figure 1). Each sensor has a unique serial number that identifies it to the bus.....

The circuit on this page is for a simple light detector circuit board that has 8 detectors that can be used with visible or infrared light systems. The detectors use LM339 voltage comparators as the active element. Phototransistors or CdS photocells can be....

Thanks to the S6986, the circuit is very simple and requires few components. D2, D3, D5 and D6 forms a bridge rectifier allowing to plug the sensor connector brick in any direction. C1 filters power supply, it must be connected near to IC1 to bypass it....

A single zone alarm circuit with entry and exit delay and other facilities. 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....

It's basically a photovore with a couple tactile sensors. It's rather complex but can give neat behaviors with modifications to the circuit. At this point I don't have any plans to give more information on this circuit so your on your own. C1 and C2 values....

This project entitled Remote Control Through Internet allows us to monitor, control and automate our home from remote locations. In existing system home automation and security are separate systems working independently. Also in existing system if any one....

Using this low cost Project one can reproduce AUDIO from TV without disturbing anyone. It does not use any wire between TV and HEADPHONE. In place of pair of wires it uses invisible Infrared light to transmit audio signals from TV to Headphone. Without using....

The circuit in Figure 1 provides a way to check a battery`s condition. Measuring a battery`s voltage is not the best way to check its condition; it`s better to measure the power that the battery delivers in a discharge process to evaluate the battery`s....

Here is an interesting circuit for a magnetic proximity switch which can be used in various applications. The magnetic proximity switch circuit, in principle, consists of a reed switch at its heart. When a magnet is brought in the vicinity of the sensor....

When you connect remote sensors to a central process controller, a simple, robust, and commonly used interface is the 4- to 20-mA loop. The advantages of this current loop include the simplicity of just two twisted wires that share both power and signal, the....

By combining the responses of an Analog Devices (www.analog.com) AD590 temperature sensor and a Humirel (www.humirel.com) HS1101 humidity sensor, you can generate a single TTL-level signal containing information from both sensors (Figure 1). This design uses....

The sensors used are silicon phototransistors and Cadmium Sulfide (CdS) photocells. Both of these sensors allow less current to flow when they are dark than when lighted. Phototransistors change their conductance while photocells change their resistance....

Using a product developed for PC-motherboard environmental monitoring, you can configure a low-cost, general-purpose DAS (data-acquisition system) (Figure 1). The DAS can directly monitor multiple voltage channels as well as temperature and frequency. It can....

Variable-reluctance sensors are preferred for industrial and automotive environments, because they sustain mechanical vibration and operation to 300°C. In most applications, they sense a steel target that is part of a rotating assembly. Because the....