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Moving message display using LEDS

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learner71

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Dear Friends,
I want to make moving message on LEDs. But i am not able to make diagonal leds on. Can anyone tell me, how can i make diagonal leds on.

When i am doing this, it makes all the leds in on state.

I am totally confused, how others are doing this?

--------
Learner
 

KerimF

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Hi learner,

Let us assume we have 8x8 pixels connected as a matrix so that we have 8 terminals for rows and 8 terminals for columns.

Let us also assume that each row is a common cathode and each column is a common anode.

So, when a row terminal is connected to ground (by an NMOS transistor for example), every LED that has its PMOS transistor on (to Vcc), will light.
To produce a frame having diagonal on LEDs, it is necessary to drive the LEDs as the following steps:

Turn on row 1 and col 1
Turn on row 2 and col 2
....
Turn on row 8 and col 8
Then again
Turn on row 1 and col 1
... etc

The trick is, we need to make these steps quickly so that the eye will see a frozen frame. Therefore the period of each step should be made rather short.
For this 8x8 matrix, I am sure that a period of 2ms is adequate but you can always experiment the effect produced by longer periods than 2ms.

Kerim
 

babatundeawe

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checkout this site for tutorial thogh its in assembly language but u will get the basic talkingelectronics.com
 

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