Laser Track Detection
The following diagram shows the basic laser pointer circuit. It is identical to the infrared circuit except that the infrared LED`s have been replaced by the la...
Laser Track Detection
The following diagram shows the basic laser pointer circuit. It is identical to the infrared circuit except that the infrared LED`s have been replaced by the la...
Remote Thermometer circuit
This circuit is intended for precision centigrade temperature measurement, with a transmitter section converting to frequency the sensor`s output voltage, which...
Remote Thermometer circuit
This circuit is intended for precision centigrade temperature measurement, with a transmitter section converting to frequency the sensor`s output voltage, which...
Hall effect sensor as Toilet Tank Refiller
The 12 Volt power in my application comes from a small solar power system, it may also be provided by a suitable wall-wart DC power supply. The cistern is locat...
Hall effect sensor as Toilet Tank Refiller
The 12 Volt power in my application comes from a small solar power system, it may also be provided by a suitable wall-wart DC power supply. The cistern is locat...
model train detector using photocell
This photocell is best mounted at tie level between the rails. The variable resistor adjusts the sensitivity of the circuit. This circuit can be powered by eith...
model train detector using photocell
This photocell is best mounted at tie level between the rails. The variable resistor adjusts the sensitivity of the circuit. This circuit can be powered by eith...
Pine Racecar Victory Judge
I have received countless emails asking for a circuit to tell the user which car won in a pine car (also called Pinewood Derby, Cub Car, Scout Car, etc.) race. ...
Pine Racecar Victory Judge
I have received countless emails asking for a circuit to tell the user which car won in a pine car (also called Pinewood Derby, Cub Car, Scout Car, etc.) race. ...
Load Sensing Automatic Switch
The circuit of the mains current detector is shown in Figure 1. By using a few cheap diodes, a resistor, LED and LDR, a simple opto-isolated detector can be cr...
Load Sensing Automatic Switch
The circuit of the mains current detector is shown in Figure 1. By using a few cheap diodes, a resistor, LED and LDR, a simple opto-isolated detector can be cr...
Lightning Activated Camera Shutter Trigger
This circuit is used to trigger a camera`s electronic shutter circuit when a flash of lightning is present. This circuit would also work for photographing firew...
Lightning Activated Camera Shutter Trigger
This circuit is used to trigger a camera`s electronic shutter circuit when a flash of lightning is present. This circuit would also work for photographing firew...
Whistle Switch
The whistle switch allows you to turn on, or off, an appliance by whistling at it. I originally built the whistle switch in 1974. Do not attempt to duplicate it...
Whistle Switch
The whistle switch allows you to turn on, or off, an appliance by whistling at it. I originally built the whistle switch in 1974. Do not attempt to duplicate it...
Photo Detector Circuits
This page features basic, visible light photo-detector circuits that can be used to detect trains. These methods would normally be used with the photo sensor mo...
Photo Detector Circuits
This page features basic, visible light photo-detector circuits that can be used to detect trains. These methods would normally be used with the photo sensor mo...
Infrared Light Train Detection
This page presents information on infrared - `Across The Track` train detection circuits. The circuits are designed around the LM339 comparator chip and can use...
Infrared Light Train Detection
This page presents information on infrared - `Across The Track` train detection circuits. The circuits are designed around the LM339 comparator chip and can use...