The Water Level Indicator employs a simple mechanism to detect and indicate the water level in an overhead tank or any other water container. The sensing is done by using a set of nine probes which are placed at nine different levels on the tank walls with probe 9 to probe 1 placed in increasing order of height, common probe i.
When the water-level is below the minimum detectable level MDLthe seven segment display is arranged to show the digit 0, indicating that the tank is empty, when the water reaches level1 but is below level2 the connection between the probes gets completed through the conducting medium — water and the base voltage of transistor increases.
This causes the base-emitter junction of transistor to get forward biased, this switches transistor from cut-off to conduction mode thus PIN B7 of microcontroller is pulled to ground hence, the corresponding digit displayed by the seven segment display is 1.
The similar mechanism applies to the detection of all the other levels. When the tank is full, all input pins of microcontroller become low. Most water level indicators are equipped to indicate and detect only a single level. The Water Level Indicator implemented here can indicate up to nine such levels and the microcontroller displays the level number on a seven segment display. So, the circuit not only capable of cautioning a person that the water tank has been filled up to certain level, but also indicates that the water level has fallen below the minimum detectable level.
This circuit is important in appliances such as the water cooler where there is a danger of motor-burnout when there is no water in the radiator used up also it can be used in fuel level indication. In this project we show the water level indicator using eight transistors which conducts as level rises, a buzzer is also added which will automatically start as the water level becomes full, auto buzzer start with the help of microcontroller. With the help of this project we not only show the level of water on seven segment display but also indicate the water full condition using a buzzer.
The operation of this project is very simple and can be understood easily. As in this case the microcontroller is used in the active low region which means it considers volts for HIGH and volts for LOW now the output of transistor which is 4. Now as the water starts filling in the tank a conductive path is established between the sensing probes and the common probe and the corresponding transistors get sufficient biasing at their base, they starts conducting and now the outputs will be Vce i.
Here the microcontroller is programmed as a priority encoder which detects the highest priority input and displays corresponding water level in the seven segment display. In this project while the water level reaches the 7th level i. When the tank becomes full, the top level probe gets the conductive path through water and the corresponding transistor gets into conduction whose output given to microcontroller with this input microcontroller not only displays the level in seven segment display but also activates the continuous buzzer by which user can understand that tank is full and can switch off the motor and save water.
Flow chart gives the clear and easy understanding of the project. The process goes on as follows: The microcontroller checks for tank full condition, if the condition is satisfied it indicates the same on display unit and also sounds a buzzer if the condition fails it checks again and this process continues and the corresponding level is indicated in the display unit.When prototyping a new circuit, often the goal is to get a proof-of-concept working as soon as possible to iron out all of the bugs it might have.
The power supply can easily be an afterthought, and for smaller projects we might just reach for an adjustable LM voltage regulator to dial in the correct voltage and then move on with the meat of the project. These linear regulators are incredibly inefficient though, so if you find yourself prototyping with one of these often enough, it might be worthwhile to switch to something better. This one is based on the relatively popular LMAdj chip which handles the switching frequency part of the circuit automatically.
You will also need some large capacitors, an inductor one of the disadvantages of an SMPS circuit and a small potentiometer to use as the feedback control for the LM This special pin allows the output voltage of the SMPS to be precisely controlled. One of the design choices he made was to use a switching power supply. The LM datasheet has no problem sourcing 3A at 5V and in addition to two electrolytic capacitors which are commonly used with linear regulators, you just need to add a diode and an inductor.
The meter offers several different configurations which are set on the PC side of things.
LM2576 3-Ampere Step-Down Voltage Regulator
These include the colors that are used and if the entire bars is used as one meter or split into sections to display both audio channels. Check it out after the break. By using our website and services, you expressly agree to the placement of our performance, functionality and advertising cookies.
Learn more. Search Search for:.LM is a switch-mode step down Buck Converter voltage regulator that can provide a fix output voltage. Its output voltage can also be adjusted in a range of 1. This IC is very simple to use, and this feature makes it ideal for a wide range of applications.
It has built-in fault protection against over currents, voltages and temperature. This picture depicts a pinout diagram of an LM buck voltage regulator.
It works either in fix voltage or in adjustable voltage mode. For details of each pin, refer to the next section. It is important to know the description of pins of IC before using it.
The functions of all the pins of LM are explained below:. The feedback is an input pin used to set output voltage in case of adjustable output. To adjust the output voltage, it is connected to the midpoint of the feedback divider network.
In case of fixed output, connect this pin to the capacitor. It is the enable input pin. This pin should not be left unconnected. Connect it to the ground to enable the voltage regulator.
To disable the regulator, connect this pin to HIGH logic. It is suitable for driving 3A loads. Due to its convenient use, it is also used as a step-down switching regulator.
It can use readily available inductors. This feature makes it ideal for designing switch-mode power supplies as it greatly simplifies their design.
If you are looking for a linear buck voltage regulator that can drive 3A loads and provide an output in the range of 1. The use of this chip is explained through the circuit given below. In this section, we will see examples of how to use LM in fix voltage and adjustable voltage mode.
An input capacitor is required for stability. The output capacitor acts as a filter and removes ripples from the output voltage. It also provides loop stability.
A Schottky diode 1N connects across an output pin and L1 inductor. When regulator internal switch is off, it offers a path for inductor current. Before selecting a Schottky diode, you should make sure that the rating of this diode is 1.
To adjust the output voltage, two resistors R1 and R2 are connected which constitute a feedback network. The output voltage or the values of resistors can be calculated by keeping two values constant and put them in the following equation to find third value:. The LM is a high-efficiency Buck regulator which is used in a large variety of applications which include:.In this blog entry, I describe a constant-current LM power supply.
How to build an adjustable switching power supply using LM2576 [Buck Converter, CC-CV]
Below is a picture of the supply, mounted into a section of aluminum square tubing. I already have a nice commercial power supply on my bench, but whenever I need some additional power, such as 5V DV, I end up grabbing a wall wart. I decided to finally build my owned fixed power supplies for the bench. The following is my hand-drawn schematic on a whiteboard from the youtube video I made of the supply:. LM power supply schematic, hand-drawn, on whiteboard. Starting at the top-left, we have the LMadj regulator.
The potentiometer top-center in the schematic will serve as our voltage divider. In my reference build, I used a board-mounted turn pot. On the output pin of the LM there is a diode, inductor, and capacitor. Those are boilerplate, right out of the datasheet. I used a uH inductor and a 1n diode. The output capacitor can be sized according to your needs.
I currently have a uF 16V installed. To the right of the output capacitor is a 1 ohm resistor. We can take a voltage reading from the the points at the left and right of the sense resistor.
The voltage measured will be equal to the current that is flowing out of the supply. I have a big bag of precision 10 ohm resistors for just this purpose. Beneath the sense resistor is the first of two op-amps. This one serves as a differential amplifier. Consider a 5V supply with a ma load.
The voltages on the left of the sense resistor will be 5. The op-amp is responsible for doing that subtraction 5. The output of the op-amp is a voltage between 0 and 1 V voltage that reflects 0 to 1 A current in the sense resistor. The output of the first op-amp is a perfect place to hang a digital panel meter. Bottom-right is a second op-amp the TLC includes two op-amps per chip, so this works out great.
This op-amp takes the V current sense signal from the first op-amp as well as a 0 — 1V current limit signal from a potentiometer. This is our current limit control.
Thread starter takao Start date May 15, Search Forums New Posts. Thread Starter takao Joined Apr 28, 3, It is a LM simple switcher 3. Gate drive is done with a small transformer, which on the input side has 47 Ohms dampin resistor. Another transformer same model is also used for the LM supply.
There is no input capacitor, only a large ferrite coil. Which will emit noises, if I increase the input voltage, and also output voltage. At lower output voltages, it remains quiet.
One improvement was already made, adding a reset loop to the gate drive transformer. Adding the reset loop, noise in the filter coil not seen in the photo is greatly reduced. Are there additional circuits that I can add to the transformer drive?
Any good websites? The proto circuit is built that way in order to make changes as required, without too much effort. Isn't the way I build circuits in general. Scroll to continue with content. It would probably be very helpful if you posted a circuit diagram rather than your photo of a bundle of wires. I don't really see the need for the transfo. I have posted elsewhere since I did not receive replies here. However, it is not so much important for me, since I use a TL circuit now, for upto 12A.
Looks like you did not get much help there either. I don't understand why you moved to PNP, that will cause a lot of unnecessary heat waste.
Indeedwhy pMOS to start with. The idea of using a transfo is surely to provide a floating output. That would also mean you could reduce the current you need to drive the transfo.
Diagram of Metal Detector Project in PDF
Tho' I could not find the current required by the chip If you have access to a 'scope, you could evaluate the inductors by measuring the ringing frequency of an LC pair with a know capacitance. I may try this sort of cct. I have an adjustable LM25xx somewhere and those sort of coils form PC motherboards. In fact I think you are way too small there and that maybe why you are heating the diode.We deliver up-to-date correct, authentic data based on evaluation unbiased at no cost to you.
To do this, we display ads from only trusted Partners. To continue on our site, simply turn off your ad blocker and refresh the page. The operation of metal detectors is based upon the principles of electromagnetic induction.
Metal detectors contain one or more inductor coils that are used to interact with metallic elements on the ground. The single-coil detector illustrated below is a simplified version of one used in a real metal detector. A pulsing current is applied to the coil, which then induces a magnetic field shown in blue. When the magnetic field of the coil moves across metal, such as the coin in this illustration, the field induces electric currents called eddy currents in the coin.
The eddy currents induce their own magnetic field, shown in red, which generates an opposite current in the coil, which induces a signal indicating the presence of metal. This project focuses on the adaptation, simulation and construction of a commonly available schematic for a Pulse Induction PI metal detector.
The background information of the history and uses of metal detectors is presented as well as the design criteria for out particular project. The theory behind how a basic PI metal detector works is examined, along with the basic details of a readily available design for a detector.
A detailed examination of the chosen schematics and the function of each component is examined and explained, as well as explanations for certain choices of component values. The results of a computer simulation using Pspice are shown, and then the results of the actual construction of a breadboard prototype, along with the problems encountered are examined. Your email address will not be published. Save my name, email, and website in this browser for the next time I comment.
In this article, we will learn to build a variable step-down buck converter using the popular LMAdj chip. Easy to adjust the parameters optimum use of variable resistors to control the voltage and current.
Figure-1 shows the schematic diagram of the power supply. The heart of the circuit is the LMAdj chip. It is a popular, cheap, and handy buck converter IC. It is capable of driving 3A load with excellent line and load regulations. These devices are available in fixed output voltages of 3. TS series operates at a switching frequency of 52kHz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. It substantially not only reduces the area of board size but also the size of a heat sink, and in some cases, no heat sink is required.
External shutdown is included. Capacitors C1 and C2 are used to reduce input noise. Simply it means using two uF capacitors in parallel is better than using a big uF capacitor. R1 to R4 construct a shunt resistor. I have used four 0.
The current flow over this resistor generates a voltage drop, which we used it to sense the current. IC1 is used to amplify the voltage drop on the shunt resistor because small current flows do not make a big voltage drop over a 0. So we have to use an amplifier here. IC1 is configured as a non-inverting amplifier that can deliver x gain maximum. Potentiometer R7 defines the gain, so the minimum gain is around 4x. Therefore this potentiometer defines the maximum output current.
The potentiometer R6 adjusts the output voltage. The diode D2 blocks the feedback voltage path to IC1. C5, C6, and C7 are used to reduce the noise.