Go Down

Topic: Led Matrix 24x10 (Read 577 times) previous topic - next topic

samjack

Hello,

I want to make a led matrix of 10 lines and 24 columns.
But i have a question about powering the leds.

I created a 5x5 matrix, but when 1 line of 5leds is on, the leds are dimmed

The lines are powered with a 74hc595 and the columns with another 74hc595 with on each output pin a resistor and NPN for the ground.

I don't want this problem in my 10x24 matrix.
what must i be used for powering up the matrix?

each led must have the full brightness (20mA)
i want to switch 480mA, but the 74HC595 connat and tpic6B595 is only sink.

who can help me?

my local parts shop say to use a 74LS595, but see no difference

What about a 4017 decade counter for sinking?

CrossRoads

74HC595 controlling PNP transistors to source current into anodes, 74HC595 controlling ULN2803 to sink current from cathode columns.
200mA to sink per column.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Grumpy_Mike

Depending on the way you wire it up will depend on the software you need to multiplex it.
http://www.thebox.myzen.co.uk/Workshop/LED_Matrix.html


Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy