Moisture deposited on a surface bridges across a grid of wires or circuit board traces. A circuit measures the AC ohms resistance through the grid. - Warm wet weather promotes fungus and insect pests of plants. - Quick detection of rain can be used in controllers for greenhouse windows and the like. - Grids can be used to detect the moisture in breath, condensation
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from steam, or spray from industrial or other processes. Stainless steel electrodes are embedded in a block of plaster of paris (gypsum) or in a proprietary mixture. Watermark ™ sensors are "granular matrix" devices, that have a fine sand aggregate along with gypsum crystals, held inside a permeable membrane and stainless steel sleeve. The purpose of the gypsum is to buffer the conductance measurement from ions that are found in uncontrolled amounts in the soil. This device is buried in close contact with soil, and reaches an equilibrium with the soil moisture. The AC ohms resistance of the block can be correlated with soil moisture or with evidence of plant stress. We have an assembled " SMX " module available for reading the resistance of Watermark blocks into the OWL2 or BASIC Stamp. Electrodes touch the surface of the water, to indicate attainment of a certain water level. This can initiate an action or alarm, or operate a sump pump. An output can be taken as the water moves up and down a pair of electrodes, and the level is correlated with resistance values on the scale. The signal depends on both the water level and on the specific conductivity of the water. See Earth Measurements, units 5 and 6. By making the water fill an exact geomerical space, the variable becomes the conductivity of the water. The circuit measures the resistance of the water at a certain temperature, which is measured at the same time....
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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