This is a two-way can set the alarm circuit which uses a Schmitt IC, with responsive and sound and light show, small size, low power consumption, all of the elements is only 13, a very low cost. This circuit is divided into two parts by the A, B and R4,
Click here to download the full size of the above Circuit.
C1 composition limit alarm. And in C, D and R5, C2 constitute the lower limit alarm function, the circuit shown in Figure 1.Usually RP1, RP2 are provided two upper and lower alarm point, the A and C inputs are high, the outputs are low leaving the oscillator are halted. When the temperature is too high, the thermistor resistance R1 decreases, the output high A, B start-up, the piezoelectric ceramic YD a high-pitched beep. At the same time, the light emitting diode LED1 lights on to indicate overheating. When the temperature is too low, the thermistor R2 resistance increases output high of C, D start-up, the piezoelectric sheet issued YD bass tone beep. Light emitting diode LED2 display temperature is too low.Since CMOS circuit static power consumption is extremely small, only microampere current level, so static power consumption mainly in the RP1, RP2 and thermistors. If we can use resistance at more than a hundred k special temperature resistance, RP1, RP2 a corresponding increase in the scale drawing press, the static power consumption can be controlled very small, it is extremely beneficial to prolong battery life.Component list as follows: Number Name Type Quantity R1,2 thermistor 1K 2 R3 resistance 3K 1 R4,5 resistance 2M 2 RP1,2 adjustable resistor 10K linear 2 Polyester capacitors C1 300P 1 Polyester capacitors C2 1000P 1 LED1,2 emitting diode µ3mm 1 Schmidt integrated circuit or IC CD4093 MC14093 1 YD piezoelectric buzzer µ20mm HTD20A-1 type 1 E battery lighter dedicated 12V small battery 1 The alarm uses the components is not large, do like so small matchbox.If instead of using photosensitive resistance thermistor can be used as the light intensity alarm. It can also be the other input of the Schmitt trigger use down as light, temperature bifunctional two-way alarm. It leads to a control signal from the LED fill light, humidification (ultrasonic humidifier) to compose automatically fill light and humidity controller.
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.....
characters left: