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Heart Rate Sensor – Circuit Schematic
Heart Rate Sensor
Here is the inside of the light reflectance sensor (top) and a schematic drawing of it's circuitry (bottom). First, carefully remove the phototransistor as show...
Heart Rate Sensor – Circuit Schematic
Heart Rate Sensor
Here is the inside of the light reflectance sensor (top) and a schematic drawing of it's circuitry (bottom). First, carefully remove the phototransistor as show...
Infrared Interruption counter – Circuit Schematic
Infrared Interruption counter
Infrared interruption counter is a reliable circuit that takes over the task of counting number of interruptions very accurately. When somebody enters into the ...
High Precision Temperature Indicator – Circuit Schematic
High Precision Temperature Indicator
This project is an High precision digital thermometer which indicates the temperature on the seven segment display. It has an resolution of 0.06deg. The 1 wire...
Rain Detector – Circuit Schematic
Rain Detector
This circuit uses a sensor made of a small piece of etched PC board and a simple SCR circuit to detect rain and sound a buzzer. The SCR could also be used to ac...
Auto Stud Sensor – Circuit Schematic
Auto Stud Sensor
This thing is a very nifty capacitive sensor. For you europeans, this little gem is used in north america mostly for detecting wooden beams behind drywall or pl...
CDV700 Geiger Counter – Circuit Schematic
CDV700 Geiger Counter
This project involves making several modification to an early 1960s era Victoreen CDV700 or CDV600-6B geiger counter. These counters are available on E-Bay for ...
Leak Detector – Circuit Schematic
Leak Detector
High sensitivity, portable temperature comparator. This sensitive circuit is basically a comparator, detecting very slight temperature changes in respect to the...
Live line Detector – Circuit Schematic
Live line Detector
Detects the presence of a live mains conductor. Minimum parts counting. If the unit is brought close to a live conductor (insulated, and even buried in plaster...
Liquid level Alert – Circuit Schematic
Liquid level Alert
This circuit will emit an intermittent beep (or will flash a LED) when the water contained into a recipient has reached the desired level. It should be mounted ...
Infra-red Level Detector with 555 – Circuit Schematic
Infra-red Level Detector with 555
Useful for liquids level detection and proximity devices Up to 50 cm. range, optional relay operation. This circuit is useful in liquids level or proximity det...
Plant Watering guard with 4093 – Circuit Schematic
Plant Watering guard with 4093
A flashing LED signals the necessity to water a plant Very low current consumption - 3V powered circuit. This circuit is intended to signal when a plant is nee...
Room Noise Detector – Circuit Schematic
Room Noise Detector
One LED monitors three levels: 50, 70 & 85 dB Useful to detect too noisy environments. This circuit is intended to signal, through a flashing LED, the exce...
EM Field Probe with Meter – Circuit Schematic
EM Field Probe with Meter
This tester is designed to locate stray electromagnetic (EM) fields. It will easily detect both audio and RF signals up to frequencies of around 100kHz. Note, h...
Temperature Monitor – Circuit Schematic
Temperature Monitor
Using a thermistor in the position shown makes a heat activated sensor. A change in temperature will alter the output of the opamp and energize the relay and li...
Static Electricity Detector – Circuit Schematic
Static Electricity Detector
This circuit relies upon the extra high input impedance of a FET, and also demonstrates the gate terminals sensitivity to changes in voltage. The gate termina...
Barometer – Circuit Schematic
Barometer
The Bray Barometer requires manual calibration for voltage offset and gain. Although practical on the workbench, these devices are most likely mounted in incon...
Temperature Sensor with Digital Output – Circuit Schematic
Temperature Sensor with Digital Output
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 ...
Laser Target Finder circuit – Circuit Schematic
Laser Target Finder circuit
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 br...
Laser Target Finder circuit – Circuit Schematic
Laser Target Finder circuit
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 br...