Inverting Detector Circuit

This is a design circuit for basic infrared and visible inverting detector circuit. This circuit is use LM339 voltage comparators are the active element for the controller. Here’s the figure of the circuit;

All of the comparators on the PCB are wired so that when the photo sensors are dark, the output of the comparators will be LOW and the LEDs will be ON. The detection voltage level for the circuit as shown is set at 1/2 of the supply voltage. If a lower or higher detection level voltage is needed, the values of resistors R9 / R10 and R19 / R20 can be adjusted. This circuit does not need a regulated power supply and can operate on supply voltages of up to 32 volts. The 1K output resistors can be replaced by jumper wires if they are not needed such as for inputs to control or signals circuits that have their own current limiting resistors. For phototransistors a value of 470K ohms will work for most room light situations. If the light is dim, selecting a higher value resistor such as 1 Mega ohm will give better sensitivity. This High Impedance Test Voltmeter circuit can also be used for testing phototransistors installations.

Presence Detector Circuit

Here’s circuit that react in presence of any conductor object including humans. This circuit does not detect object movement but can act as a proximity sensor! Sensitivity is adjustable with P1 which will be located at a great distance from the rest of the presence detector circuit. This is the figure of the circuit;

 

The presence detector is built with a Clapp oscillator at 1MHz. Do not bring metallic objects close to circuit! This circuit can be used as a aggressive liquid detector.

LM339D Simple Capacitive Touch Sensor Circuit

This is a circuit for capacitive touch sensor that can be used for proximity detection and touch-controlled switching. Here’s the figure of the circuit;

This is a simple circuit diagram. This circuit is use for example, a finger comes close to the sensor, it creates a capacitance to Earth with a value of 30 to 100 pF. Component: Resistor, Capacitor, Diode, LM339D IC, pin header. [Circuit diagram source: extremecircuits.net]

Capacitive Sensors Circuit

This circuit has purpose of this circuit is to animate shop-windows by means of a capacitive sensor placed behind a post-card-like banner. The card is placed against the glass inside the shop-window, and the visitor can activate the relay placing his hand on the card, from the outside. Here’s the figure of the circuit;

Parts:
R1,R2_____1M 1/4W Resistors
R3,R4____47K 1/4W Resistors
C1_______10µF 25V Electrolytic Capacitor
C2______470pF 630V Ceramic or Polyester Capacitor
D1-D3____1N4002 100V 1A Diodes
Q1-Q3_____BC337 45V 800mA NPN Transistors
RL1_______Relay with SPDT 2A @ 220V switch
Coil Voltage 12V. Coil resistance 200-300 Ohm
J1________Two ways output socket
Sensor____Aluminium or copper thin sheet with the dimensions of a post-card,
glued at the rear of the same (about 15x10.5 cm.)
Thin screened cable

Q1, Q2 & Q3 form a high impedance super-Darlington that drives the relay, amplifying the 50 or 60Hz alternate mains-supply frequency induced in the sensor by the human body. C1, D2 & D3 ensure a clean switching of the relay. Power supply can be any commercial wall plug-in transformer adapter with rectifier and smoothing capacitor, capable of supplying the voltage and current necessary to power the relay you intend to use.

Fully Linear Diode Sensor Circuit Based On The A748 IC

This circuit is design for full linear diode sensing circuit. Here’s the figure of the schematic circuit; 

This circuit based on the A748 IC. Features: op amp as constant-current source, 1 V at  50 degrees Celcius. Diode or Transistor Makes Fully Linear Thermometer. Component: A748 IC, Resistor, Capacitor, Diode.

Devantech SRF04 UltraSonic Sensor Circuit

This is a design circuit for about Devantech SRF04 UltraSonic Sensor To The SV203 powered PPRK Circuit Diagram. Here’s the figure of the circuit;

This circuit based on the Devantech SRF04 sensor. Features: minimum of 10m sec to initiate the sonic pulse (the trigger), fairly simple, held low (logic 0) input line. Component: Capacitor, Resistor, Junk, IC, Battery, Infrared, Transistor.

Robotics IR Navigation Sensor Circuit

This is a design circuit about Robotics IR Navigation Sensor Circuit Diagram. This is the figure of the circuit;

Features: one chip 74HC04, IR sensor will work in direct sun light, Sharp GP1U581Y, very good range. Component: IC, Resistor, Capacitor, Diode, Transistor.

Dew Detector Probe Circuit

This is a circuit for Dew Detector Probe circuit works on 5V dc supply. It is useful for checking the presence of dew (condensed moisture) inside sensitive electronic devices like VTR, camera, copier, computer etc. This is the figure of the circuit;

The principle of the ready made dew sensor element is based on the change in resistance of a conductive polymer in a thin film on a small ceramic substrate. As the sensing polymer wet (90 to 95% Relative Humidity), its resistance will increase drastically because the polymer expands and therefore causes a larger distance between the conductive particles. After successful construction, enclose the whole unit in a small aluminum tube.

Bosch LSU 4 Sensor and WEGO Circuit

That is a design circuit that shows about Bosch LSU 4 Sensor and WEGO Circuit Diagram. Here’s the figure of the circuit;

Features: included built-in data logging, used the new Bosch LSU 4.2 wide-band sensor, substantially less than the price of the original unit, much lower cost. Component: Power Supply, Resistor, Transistor.