SHRIRAM SPARK

THINK DIFFERENT

Month: October 2013

1.25 V TO 37V – 1.5A VARIABLE, ADJUSTABLE POWER SUPPLY USING LM317

A well designed and variable power supply for electronics hobbyists and DIY’ers is a must, you don’t want to spend a huge amount of money in batteries [On the long run]. A variable power supply can come in handy for testing and powering  any project you are building. The mentioned power supply ranges from 1.25V – 37V @ 1.5A using the famous LM317 voltage regulator. LM317T is a very famous IC and easily available in the market comes with 3 pins, supporting input voltage is from 3 volt to 40 volt DC and delivers a stable output between 1.25 volt to 37 volt DC.
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THREE REASONS TO TAKE DIY TO THE NEXT LEVEL

Whether you are watching it on television or searching for it on Pinterest, chances are you have admired a few Do It Yourself (DIY) projects recently. Have you taken it a step further and actually completed a DIY project? There are three key reasons why the trend of DIY projects is so popular.

Fun

The first reason that people want to try a DIY project is usually because it sounds like fun. You learn a new skill and the end result will be just what you are looking for. Since Halloween is just around the corner you may be thinking: “Should I go searching for the perfect costume or should I try to design and sew it myself?” Not everyone would have an interest and natural ability in making their own costume so learning to sew would seem like fun. Chances are you are artistic and enjoy ways to tangibly express that creativity. Now imagine taking it one step further and Continue reading

SOUND GIVES OBJECTS A HUMAN TOUCH

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Touch screens are so ubiquitous that physical keyboards are becoming a thing of the past, at least for mobile devices. Now imagine if the capability of touch spread from the display to the entire device, allowing control by gently pressing on any part of the phone, or even making any household item into a touch-sensitive interface with your computer.

Anything solid vibrates a specific way when it’s hit physically with another object or with sound waves. The characteristic is called resonance. For example, when you tap on a crystal glass, it vibrates at a certain frequency, producing a ring. If you hit it with sound waves — for example, the ambient background noise in a room — it vibrates at a different frequency. Grip the glass while it rings, and the sound stops. Continue reading

SMART SMOKE ALARM

For a device created to save lives, the household smoke detector sure takes a lot of heat for being annoying: the false alarms when the cookies get burned, the incessant beeping when the battery needs changing and all those times standing on wobbly chairs while trying to find minuscule buttons.

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POWER AND THERMAL DISSIPATION

As your embedded project grows in scope and complexity, power consumption becomes an ever more apparent issue. As power consumption increases, components like linear voltage regulators can heat up during normal operation. Some heat is okay, however when things get too hot, the performance of the linear regulator suffers.

How much is too much?

A good rule of thumb for voltage regulators is if the outer case becomes uncomfortable to the touch, then the part needs to have an efficient way to transfer the heat to another medium. A good way to do this is to add a heat sink as shown below.

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FLEXIFORCE PRESSURE SENSOR – QUICK START GUIDE

Introduction

This is a quick how-to explaining everything you need to get started using your Flexiforce Pressure Sensor.  This example uses the 25lb version, but the concepts learned apply to all the Flex sensors.

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Requirements

Necessary hardware to follow this guide:

  • Arduino UNO or other Arduino compatible board
  • Flexiforce Pressure Sensor
  • Breadboard
  • M/M Jumper Wires
  • 1 MegaOhm Resistor  Continue reading

WHY SHOULD YOU DE-RATE CAPACITORS

Capacitors Galore

Capacitors are one of the most common elements found in electronics, and they come in a variety of shapes, sizes, and values. There are also many different methods to manufacture a capacitor. As a result, capacitors have a wide array of properties that make some capacitor types better for specific situations. I would like to take three of the most common capacitors – ceramic, electrolytic, and tantalum – and examine their abilities to handle reverse and over-voltage situations. Note: several capacitors were harmed in the making of this post.

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Ceramic Capacitors

The most common capacitor is the multi-layer ceramic capacitor (MLCC). These are found on almost every piece of electronics, often in small, surface-mount variants. Ceramic capacitors are produced from alternating laye Continue reading

UNDERSTANDING POWER FACTOR AND WHY IT'S IMPORTANT

Power factor is a measure of how effectively you are using electricity. Various types of power are at work to provide us with electrical energy. Here is what each one is doing.

Working Power – the “true” or “real” power used in all electrical appliances to perform the work of heating, lighting, motion, etc. We express this as kW or kilowatts. Common types of resistive loads are electric heating and lighting.

An inductive load, like a motor, compressor or ballast, also requires Reactive Power to generate and sustain a magnetic field in order to operate. We call this non-working power kVAR’s, or kilovolt-amperes-reactive.

Every home and business has both resistive and inductive loads. The ratio between these two types of loads becomes important as you add more inductive equipment. Working power and reactive power make up Apparent Power, which is called kVA, kilovolt-amperes. We determine apparent power using the formula, kVA2 = kV*A.

Going one step further, Power Factor (PF) is the ratio of working power to apparent power, or the formula PF = kW / kVA. A high PF benefits both the customer and utility, while a low PF indicates poor utilization of electrical power.  Continue reading

RFID TECHNOLOGY

Radio-Frequency Identification (RFID) is technology that allows machines to identify an object without touching it, even without a clear line of sight. Furthermore, this technology can be used to identify several objects simultaneously. RFID can be found everywhere these days – anything from your cat to your car contains RFID technology. This post will cover how RFID works, some practical uses, and maybe even some example code for reading RFID data.

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What is RFID?

RFID is a sort of umbrella term used to describe technology that uses radio waves to communicate. Generally, the data stored is in the form of a serial number. Many RFID tags, contain a 32-bit hexadecimal number. At its heart, the RFID card contains an antenna attached to a microchip. When the chip is properly powered, it transmits the serial number through the antenna, which is then read and decoded. Continue reading

HOW IC 555 TIMER WORKS? – DETAILED WALKTHROUGH

Pin-wise functioning of IC555 timer

Pin-1, GROUND: It is the GROUND PIN of the IC. The negative terminal of DC power supply or battery is connected to this pin. Here note that IC555 works always on single rail power supply and NEVER on dual power supply, unlike operational amplifiers.

Also note that this pin should be connected directly to ground and NOT through any resistor or capacitor. If done so, the IC will not function properly and may heat up and get damaged. This happens because all the semiconductor blocks inside the IC will be raised by certain amount of stray voltage and will damage the IC. Refer the block diagram of the IC for more details. For more details read elaborate collection of FAQ on this IC.

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Pin-2, TRIGGER It is known as TRIGGER PIN. As the name suggests in triggers i.e. starts the timing cycle of the IC. It is connected to the inverting input terminal of  trigger comparator inside the IC. As this pin is connected to inverting input terminal, it accepts negative voltage pulse to trigger the timing cycle. So it triggers when the voltage at this pin LESS THAN 1/3 of the supply voltage (Vcc). Continue reading

PULSE WIDTH MODULATION [PWM]

Pulse width modulation is a fancy term for describing a type of digital signal. Pulse width modulation is used in a variety of applications including sophisticated control circuitry. A common way we use them is to control dimming of RGB LEDs or to control the direction of a servo motor. We can accomplish a range of results in both applications because pulse width modulation allows us to vary how much time the signal is high in an analog fashion. While the signal can only be high (usually 5V) or low (ground) at any time, we can change the proportion of time the signal is high compared to when it is low over a consistent time interval.

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Robotic claw controlled by a servo motor using Pulse Width Modulation

Duty Cycle

When the signal is high, we call this “on time”. To describe the amount of “on time” , we use the concept of duty cycle. Duty cycle is measured in percentage. The percentage duty cycle specifically describes the percentage of time a digital signal is on over an interval or period of time. This period is the inverse of the frequency of the waveform.

If a digital signal spends half of the time on and the other half off, we would say the digital signal has a duty cycle of 50% and resembles an ideal square wave. If the percentage is higher than 50%, the digital signal spends more time in the high state than the low state and vice versa if the duty cycle is less than 50%. Here is a graph that illustrates these three scenarios:

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LED LIGHT BAR HOOKUP

INTRODUCTION

LED Light Bars are a super-easy way to add some extra-bright and colorful illumination to your project. Each Light Bar is essentially a set of three super-bright 5050-size LEDs. They’re offered in a variety of colors including white, red, blue, and green.

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While these bars are very simple devices, they do have a few quirks when it comes to using them. Like the fact that their nominal operating voltage is 12V. In this tutorial we’ll go over some of the important specifications of these LED Light Bars. Then we’ll dive into some example circuits that can help you get the most of these nifty little LED assemblies.

Hardware Overview

A glance at the LED Bars will reveal that there’s not a whole lot required to interface with them. There are two pairs of wire pigtails coming off the sides, labeled ‘+’ and ‘-’. The darker-gray wire connects to the ‘+’ pin, and the white wire connects to ‘-’ on both sides.

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