Saturday, June 16, 2012

DRAM cell operation

What is DRAM?

   Dynamic random-access memory (DRAM) is a type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. Since capacitors leak charge, the information eventually fades unless the capacitor charge is refreshed periodically. Because of this refresh requirement, it is a dynamic memory as opposed to SRAM and other static memory.

Operation :

1. Drive bit line
2. Select row
1. Precharge bit line to Vdd/2
2. Select row
3. Cell and bit line share charges
»Minute voltage changes on the bit line
4. Sense (fancy sense amp)
»Can detect changes of ~1 million electrons
5. Write: restore the value

1. Just do a dummy read to every cell.

Hardwork can never ever fails...
Best Luck...

Sunday, June 10, 2012

Microcontroller and its application

What is microcontroller?

A highly integrated chip that contains all the components comprising a controller. Typically this includes a CPU, RAM, some form of ROM, I/O ports, and timers. Unlike a general-purpose computer, which also includes all of these components, a microcontroller is designed for a very specific task -- to control a particular system. As a result, the parts can be simplified and reduced, which cuts down on production costs.


BPS Stands for 'Bata Positioning System'. This system provides real-time information about the current position of each team's current runner in the Batavierenrace.

Last years system used a GSM module, a GPS receiver, a microcontroller and a lot of programming. They were all connected trough a lot of wires and soldering iron. Together with some batteries it was our BPS-box. This box was sending a SMS-message every minute with the latest position of the runner.

How does it works?

Using a GPS device, we will monitor the location of a team. This location data will be parsed by a microcontroller, which then creates an SMS containing all the necessary info (including Date, Time, Speed and course). Using a GSM, which is bundled with the GPS device, this SMS will be sent to a remote server. There, the SMS messages will interpreted, entering the information they carry into a database. With this information, the exact location of each team can be projected onto a map (together with additional info like speed, and estimated time of arrival).

Hardwork can never ever fails....
Best luck....

Thursday, June 07, 2012

Sensor and it types

        A sensor (also called detector) is a converter that measures a physical quantity and converts it into a signal which can be read by an observer or by an (today mostly electronic) instrument.
        It operates based on the vibration produced by viscometer.
Viscosity Sensor Animation


  • Defect detector, used on railroads to detect axle and signal problems in passing trains
  • Engine coolant temperature sensor, or ECT sensor, used to measure the engine temperature
  • Hall effect sensor, used to time the speed of wheels and shafts
  • MAP sensor, Manifold Absolute Pressure, used in regulating fuel metering.
  • Mass flow sensor, or mass airflow (MAF) sensor, used to tell the ECU the mass of air entering the engine
  • Oxygen sensor, used to monitor the amount of oxygen in the exhaust
  • Parking sensors, used to alert the driver of unseen obstacles during parking manoeuvres
  • Radar gun, used to detect the speed of other objects
  • Speedometer, used measure the instantaneous speed of a land vehicle
  • Speed sensor, used to detect the speed of an object
  • Throttle position sensor, used to monitor the position of the throttle in an internal combustion engine
  • Tire-pressure monitoring sensor, used to monitor the air pressure inside the tires
  • Torque sensor, or torque transducer or torquemeter measures torque (twisting force) on a rotating system.
  • Transmission fluid temperature sensor, used to measure the temperature of the transmission fluid
  • Turbine speed sensor (TSS), or input speed sensor (ISS), used to measure the rotational speed of the input shaft or torque converter
  • Variable reluctance sensor, used to measure position and speed of moving metal components
  • Vehicle speed sensor (VSS), used to measure the speed of the vehicle
  • Water sensor or water-in-fuel sensor, used to indicate the presence of water in fuel
  • Wheel speed sensor, used for reading the speed of a vehicle's wheel rotation

  • Hardwork can never ever fails...

    Best luck..