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Topic: Hooking up 12v LEDs to an arduino uno (Read 1 time) previous topic - next topic

nedprz

I am hoping to use an arduino uno to drive 2 12 volt  seven segment  common anode LED displays. The displays will be used as a counter. How can I get these LEDs to work with the arduino board? The most I seem to be able to output from the board is around 5 volts.

johnwasser

Put an NPN transistor between Cathode and Ground.  Use the Arduino to turn the transistor ON and OFF.

Google: Arduino Transistor

If you need to multiplex the two digits you can use a small NPN transistor to switch a PNP transistor between +12 and the common Anode.  Use a resistor to bias the PNP base to +12 (off) and use an NPN between the PNP base and Ground to switch the PNP on.
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CrossRoads

Use two TPIC6B595 shift registers to sink the current from the segments.
Daisy chain them so 3 pins can be used to control the 14 segments.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

johnwasser


Use two TPIC6B595 shift registers to sink the current from the segments.
Daisy chain them so 3 pins can be used to control the 14 segments.


Well... yeh.  If you want to do it the EASY way.  :)
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CrossRoads

Well, there's easy, and there's masochism 8)
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

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