The QT113 is a capacitance touch sensor. Unlike many touch sensors, it does not rely on AC line voltage to be present in the room. Instead, it detects the change in capacitance the closeness of your body produces. A 2` square sensor plate can detect the closeness of your finger from several inches away. It will detect a finger even through plastic
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, glass or brick. The larger the metal sensor plate, the more the distance it will detect. The sensor plate can be as thin as a wire or as large as a metal door screen. Using the circuit above will detect proximity with the output going low when your finger is close or touching. To toggle the output, turning it on when you touch the plate once, and then turning it off when you touch it again-tie pin 3 and 4 to ground. The DC output will directly drive an LED or can go to an input of a microcontroller. Up to a point, the larger the value of the capacitor, the larger the detection distance. If you want to detect only at the front of a sensor plate, you can add a backing plate. 1/32" to 1/16" double-sided copper printed circuit board makes a good front and back plate. Here is a simple audio amplifier that will amplify various audio inputs. This amp will amplify an output pin from a Picaxe or other microcontroller to provide beeps, sound effects, or tunes. In this configuration, it has the maximum gain of 20. This motor controller can control two motors forward and reverse with speed control. They can be controlled together or independently. It is ideal for smaller Robots. By putting pins A-D high or low in different combinations, forward or reverse is effected. Sending a pulse width modulated signal to two of the pins creates the speed control. Each motor can run at up to 600ma and 36 Volts. Pins 4, 5, 12, and 13 are the...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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