The full GSM thermostat is managed by a Microchip PIC18F46K20-I/PT microcontroller, programmed with a firmware that controls the temperature and takes care of the communication with the GSM module which is the component named GSM; this is, in fact the small board hosting the cell, so the pins` numbers refer to the used pin-strips` contacts. The fi
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rmware reads the room temperature by means of a smart probe Dallas DS1820, it controls the logical condition of the opto-isolated input and commands the relay when needed. Having said that, let`s now take a look at the electric scheme, starting by the power block, that from the input voltage (power applied to PWR, + and must be a continuous current at a value between 5 and 32 V) gets a stabilized component of 3. 6 V width by means of a switching regulator. The input voltage is filtered at the bottom by the diode protecting against polarity inversion (D1) through condensers C1 and C2. Fuse F1 enables you to protect both the circuit and the power source in case of short circuit in the integrated regulator discussed below. The regulator is a U1 (a MC34063) and acts as a DC/DC converter step-down; it is used in the classic configuration of the series PWM regulators charged by inductance, whose output voltage depends on the energy stored in L1. The voltage it provides is stabilized providing feedback to the DC/DC through the demotion of a portion of the leveled component by condensers C4 and C5, made by the resistive divider R2/R3. The 3. 6 volts present in these condensers are widely filtered by other condensers placed on the power lines of the microcontroller and of the GSM module; which presents, during transmission, absorption peaks compensated for by C7, C8, C13, C14, C15 and C16, thus avoiding than an impulsive current...
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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