Thursday, March 8, 2012

A simple Arduino based Temperature logger System

LM35 are cheap yet accurate temperature Sensor from National instruments whose output voltage is linearly proportional to the Fahrenheit temperature. Its outputs 10mV for each degree rise in temperature (in Fahrenheit scale). The Arduino will measure the voltage input from the LM35 (Connected to Analog Pin 0 of the Arduino) and convert it to temperature reading in Celsius from the voltage measured and output the result to the serial port.

The connection of the Arduino with the LM35 temperature sensor is as given below ...

My arrangement on a Breadboard ...

After completing the connection on a breadboard , I build the code and uploaded it into the arduino board's microcontroller's program memory , which would be continuously read the sensor value and send the recorded values to the serial port of the computer.

In order to calculate the Celsius reading from the analog value, we use the following formula to calculate the temperature in Celsius


Val = is the value send to the computer by the serial port
tempC= is the calculated temperature value (in Celsius)
5 is the reference we are using
1024 is the resolution of the 10 bit internal ADC of the Arduino Microcontroller (ATMEGA328)

The Arduino Code :

float tempC;
 int Sensor = 0;

 void setup() {
Serial.begin(9600); //opens serial port, sets data rate to 9600 bps
 void loop()
float val = analogRead(Sensor); //read the value from the sensor tempC = (5.0 * val * 100.0)/1024.0; //convert the analog data to temperature

Serial.print("Temperature = ");
 Serial.print((byte)tempC); //send the data to the computer
delay(1000); //wait one second before sending new data

The Output (Temperature Values of the Sensor) can be monitored by Clicking the Serial monitor icon on upper right corner of the console (where you write your Arduino code) ......

I touched the Head of the Temperature sensor LM35 with a cotton soaked in icy cold water to check the working of the sensor. If every thing goes right you will be able to see the temperature values in your PC in a Tab as shown ....

Sunday, February 12, 2012


Atomtronics refers to the process of creating analogues to electronic devices and circuits using atoms. When super-cooled to form Bose-Einstein condensates, atoms placed in an Optical_lattice may form states analogous to electrons in solid-state crystalline media such as semiconductors.An atomtronic battery can be created by maintaining two contacts at different chemical potentials.Analogues of diodes and transistors have also been theoretically demonstrated.

Although atomtronic devices have yet to be realized experimentally, the properties of condensed atoms offers a wide range of possible applications. The use of ultra-cold atoms allows for circuit elements that allow for the coherent flow of information can be used in the future in quantum computers. The use of atomtronics may allow quantum computers that work on macroscopic scales and do not require the technological precision of laser controlled few ion computing methods. Since the atoms are Bose condensed, they have the property of superfluidity and, therefore, have resistance-less current in which no energy is lost or heat dissipated which is similar to superconductivity in electronics.

My AT89S51 ( Microcontroller 8051 ) Development Board made in DesignSpark PCB

I recently wanted to own a 8051 development board to practice 8051 programming I am learning in college , But The rates are just too high :( . Therefore I decided to build my own. I chosen the PCB designing software "Designspark PCB" to built my board , Which could be easily built at home using the famous copper clad board etched in ferric chloride method to build PCBs at home .

The Board Consists of the following features

  • On Board seial programmer
  • seven segment delay
  • 16x2 LCD 
  • 4x4 Keypad
  • Analog to digital Converter 
  • Comparator
  • RTC DS12887
  • Stepper motor driver
  • 8 LEDS 
  • Prototyping area , For Extending the Circuit
The Serial programming is done by using the MAX232 IC which converts signals from an RS-232 serial port  to signals suitable for use in TTL compatible digital logic circuits. Hence the .HEX generated by the computer could be directly burned into the ROM of the Microcontroller , on Board.

The stepper motor driver consist of ULN2003 IC (buffer amplifier) and Diodes to prevent Back emf from the motor to flow to the Microcontroller (which could damage your controller).

The comparator and A/D convertor consists of IC LM324 and ADC0804 respectively.

The Prototyping area can be used for building circuits to be connected to the microcontroller like sensors , Relays , RTC1307 if you are replacing the microcontroller to AT89S52 which supports I2C protocol etc. And The 16 pin Female Header connected at the upper right hand side of the board is for connecting the 16x2 LCD HD44780.

3D View of the Development Board

Back View