Friday, July 30, 2010

MSP430 LaunchPad: Cheapest Microcontroller Development Tool from TI

Source :

What is LaunchPad?

LaunchPad is an easy-to-use development tool intended for beginners and experienced users alike for creating microcontroller-based applications. At $4.30, the LaunchPad offers everything you need to get started with your projects.

The LaunchPad development kit is a part of the MSP430 Value Line series. LaunchPad has an integrated DIP target socket that supports up to 20 pins, allowing MSP430 Value Line devices to be dropped into the LaunchPad board. Also, an on-board flash emulation tool allows direct interface to a PC for easy programming, debugging, and evaluation. Included are free and downloadable software development environments for writing and debugging software. LaunchPad can be used to create interactive solutions thanks to its on-board push buttons, LEDs, and extra input/output pins for easy integration of external devices.

Why LaunchPad?

The LaunchPad is an easy-to-use, affordable, and scalable introduction to the world of microcontrollers and the MSP430 family.
Easy-to-use – LaunchPad includes all of the hardware and software needed to get started. Open source projects and code examples help users get up and running quickly.
Affordable – For $4.30, the LaunchPad includes a development board, 2 programmable MSP430 microcontrollers, mini-USB cable, PCB connectors for expandability, external crystal for increased clock accuracy, and free & downloadable software integrated development environments (IDEs) – everything you need to get started today.
Scalable – The LaunchPad is a simple introduction to the MSP430 microcontroller family. As application requirements change, programs developed on the LaunchPad can be migrated to higher end MSP430 devices.

AT89C2051 based Line Follower ROBOT

A Line following robot is the most popular beginner's choice in the world of robotics. Here is one that is controlled by a AT89C2051 microcontroller. It uses two motors that control the two rear wheels and the front wheel is free. The four infrared sensors detects a black track on floor that helps the ROBOT to follow it. LM324 IC (H-bridge driver) is used to compare the voltages from the IR sensors and L293D is used to drive the motors.


Thursday, July 29, 2010

Analog Multimeter Clock using PIC16F628A

This analog clock is something I have never thought about. It consists of three analog multimeters (for Hour, Minutes, Seconds displays) that are all in 0.5mA DC mode. The -ve ends are grounded and the +ve terminals are connected to a PIC16F628A microcontroller that keeps track of time and outputs a calculated current to each meter to display the current time.


With the use of three switch buttons, a user can set the time. The controller uses PWM (pulse width modulation) to pulse the current to the 3 meters which allows for precise needle position. The firmware was written in PICBasic Pro and there is still about 20% of the 2K PIC code space still available.

Wednesday, July 28, 2010

ATtiny45 Based PC Oscilloscope

Oscilloscopes are expensive but you can make this one for less than $10. This USB scope is based on ATtiny45 (8-pin microcontroller from Atmel). It has 2 analog inputs. The firmware in the Tiny45 is written in C and is compiled with Winavr and usb source code from obdev. As you can see, there is no crystal, the software sync the internal 16.5Mhz pll clock with the USB clock.


Tuesday, July 27, 2010

Make an Oscilloscope out of your Old B/W TV

Oscilloscopes are very versatile pieces of electronic test equipment that are used in a wide variety of applications. But they are expensive and most of the time students or hobbyists could not afford them. Here is an oscilloscope that you can make yourself with a black and white television. This oscilloscope has 20KHz bandwidth.

This project relies on sampling a waveform and then reconstructing it. The Shannon sampling theorem, which states that samples must be taken at a rate greater than twice the maximum frequency of the original signal (or at the Nyquist rate), is used so that no aliasing occurs. Aliasing occurs when a signal gets undersampled; a waveform of lower frequency will get reconstructed instead of the correct higher frequency signal. A picture is shown below to illustrate the idea:


Therefore, in this project, the sampling rate is always set higher than 40 kHz (the oscilloscope functions correctly at a maximum frequency of 20 kHz). The A-to-D converter is responsible for sampling and has a maximum sampling rate of 2 megasamples/sec.

Read details of this project @ Digital Oscilloscope

Monday, July 26, 2010

A Temperature Data Logger using PIC12F683 and EEPROM

Data loggers are electronic devices that record data over time with a built in instrument and a sensor. They are generally small, battery powered, portable, and equipped with a microprocessor, internal memory for data storage, and sensors.The data logger we are talking about records temperature of a given place over time. This project uses a 8-pin PIC12F683 Microchip along with a serial EEPROM and a thermistor (temperature sensor).

The temperature is measured and stored at user programmable intervals; this can be from 1 second to 256 seconds. The time interval is set by programming it and the start time into the EEPROM. Since most of the time the PIC stays in sleeping mode, this consumes very less power. With a EEPROM of 32KB, it is possible to record 32,000 measurements. This could be one measurement every 1 minute for 22 days for example.

Sunday, July 25, 2010

A Robotic Arm Controlled by a PC Mouse

Look at this pretty neat robotic arm that can be controlled with a standard USB mouse. In this project, a Lynxmotion robotic arm is used with a wrist upgrade, an Arduino as the brain, a USB Host shield in order to interface a regular computer mouse, and a custom made servo motor controller.

Demo video

Microcontroller-Based Water Level Indicator

This project is useful for those who have a big water storage tank on the rooftop and use a powered motor to fill it with ground water. This circuit will indicate you when the tank is about to full. It uses a PIC12F683 microcontroller as a controller and copper probes to sense the water level.

The circuit operates on 4.5V (3 AA batteries) and the PIC controller works in sleeping mode that extends the battery life.

Saturday, July 24, 2010

Interface a HD44780 Character LCD with a PIC Microcontroller

An HD44780 Character LCD is a liquid crystal display (LCD) display device designed for interfacing with embedded systems. These screens come in a variety of configurations including 8x1, which is one row of eight characters, 16x2, and 20x4. The most commonly manufactured configuration is 40x4 characters, which requires two individually addressable HD44780 controllers with expansion chips as the HD44780 can only address up to 80 characters.

These LCD screens are limited to text only and are often used in copiers, fax machines, laser printers, industrial test equipment, networking equipment such as routers and storage devices. Character LCDs can come with or without backlights, which may be LED, fluorescent, or electroluminescent. Character LCDs use a standard 14-pin interface and those with backlights have 16 pins. The pinouts are shown in figure below.

1-10 Minute Adjustable Timer using 555 IC

This project uses 555 timer  IC in monostable mode. The circuit starts timing when switched on. The green LED lights to show that timing is in progress. When the time period is over the green LED turns off, the red LED turns on and the bleeper sounds.

The time period is set by adjusting the variable resistor. It can be adjusted from 1 to 10 minutes (approximately) with the parts shown in the diagram. You can mark the times on a scale drawn on the box.


Online Resources for 555 Timer IC

The 555 timer IC was first introduced by the Signetics Corp. in 1971. It has been more 35 years and this IC is still very popular among hobbyists and is used in numerous projects. With just a few external resistors and capacitors, it can be used to build many circuits and you don't even need to understand the function of each pin in detail. It has 8-pins and it is frequently used in astable mode to generate a continuous series of pulses, and in monostable mode too when one shot or pulse of desired time period is required.

The internal block diagram of a 555 Timer IC is shown below.

Friday, July 23, 2010

LM386 Based Low Power Audio Amplifier

About LM386

LM386 is a low power audio amplifier IC designed for use in low voltage consumer applications. You can use this 8-pin IC to amplify the output signal from your mp3 player or computer audio output. The inputs are ground referenced while the output automatically biases to one-half the supply voltage. The quiescent power drain is only 24 milliwatts when operating from a 6 volt supply, making the LM386 ideal for battery operation.

Applications of LM386
  • AM-FM radio amplifiers
  • Portable cassette player amplifiers
  • Intercoms
  • TV sound systems
  • Line drivers
  • Ultrasonic drivers
  • Small servo drivers, etc.

The circuit below shows a simple audio amplifier using LM386 with a gain of 200. If the 10uF capacitor connected between pins 1 and 8 is taken off, the gain would be 20.  The gain can be adjusted between 20-200 by placing an appropriate resisor in series with this 10uF capacitor.


Operational Amplifiers (Op-Amps)

An operational amplifier (Op-Amp) is a differential amplifier that amplifies the difference of voltages applied to its two input terminals (differential input), and provides a single-ended output. The operational amplifier is an extremely efficient and versatile device. Its applications span the broad electronic industry filling requirements for signal conditioning, special transfer functions, analog instrumentation, analog computation, and special systems design.
Originally, the term, “Operational Amplifier,” was used in the computing field to describe amplifiers that performed various mathematical operations. It was found that the application of negative feedback around a high gain DC amplifier would produce a circuit with a precise gain characteristic that depended only on the feedback used. By the proper selection of feedback components, operational amplifier circuits could be used to add, subtract, average, integrate, and differentiate.
An ideal Op-Amp is basically a 3-terminal device that consists of two high impedance inputs, one an Inverting input marked with a negative sign, ("-") and the other a Non-inverting input marked with a positive plus sign ("+").

Learn more about Operational Amplifiers
I am going to provide some valuable resources available online on Op-Amp theory and applications. Check these out:

Thursday, July 22, 2010

Bipolar Junction Transistors (BJTs)

A bipolar junction transistor (BJT) is a three-terminal active electronic device that has a capability to amplify current. They are constructed of doped semiconductor materials. The three terminals are commonly known as Base, Emitter and Collector. The invention of BJT was a revolution in electronic industry. Before its invention, large size vacuum tubes were used for amplification which were less efficient, mechanically fragile and high power consuming. With the use of BJTs, the electronic design and circuits became light weight, inexpensive, and more reliable. It is called bipolar because the current flow is mainly due to two types of charge carriers: electrons and holes.
If you are a beginner student of electronics or a hobbyist, it is very important to get familiarized with the basic operating principles of BJTs, because it is the basic building block of all higher electronics technologies. I am going to provide the links below that will give you much deeper understanding of how BJT works.


I am going to start a new blog from today. My objective is to search quality electronics articles and DIY projects around the world and make them available at one platform, i.e. this blog "All Electronics". I will try to make one post everyday. I hope you will have fun browsing this blog.