Saturday, March 17, 2012

800KHz 3 Channel PWM Meter "Duty Cycle Meter"

Introduction

  After working with some motor control application i found that a multi channel PWM or Duty Cycle Meter is a quite help full to debug those PWM based motor control circuits and RGB LED control PWM using PWM which has at least 3 PWM line ,so i decided to build one for my self. 

   This is Meter has total 3 channels with all can accept frequency up 800Khz. the accuracy of the meter is quite good.

The SCHEMATIC 

Thursday, March 1, 2012

PIC MCU LCD Driver 4 commmon 7 Segmented LCD & PIC16F917

  Now a days almost all the mcu projects use a normal 16x2 char LCD or the LED  to display the data, but the problem with those 16x2 LCD and LED is , they consumes a lot of power , they are very thick  , bulky and the font size is really very small , and if you go for a big font size then they are really very expensive  and some times we just don't want that may lines and character , what we want is just a 3 - 4 digit numbers and a big display font size.
 so  here is a quick tutorial on how to use a microchip pic mcu to drive an 4 common 7 segment lcd .
Prototype


TYPES OF SEGMENTED(controller les "RAW")  LCD
     These type of LCD have no controllers built in all they are is just a liquid crystals sandwiched between to pieces of glass and sometimes a reflective plate at the back. The LCD who have that plate on the back (like my LCD has) called reflective and the LCD who don't have those plate looks quite a transparent called Transreflective.

There is another criteria for classification of the raw lcd glasses

Non Multiplexed (single Common) ( STATIC )