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Author Topic: Inverting a HIGH signal sent from an arduino  (Read 575 times)
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Hi,
I am building a project which uses a separate microcontroller to turn on some LEDs and make them flicker. The code for this is all working.

In order to turn the LED-running microcontroller on, I attached a transistor to it, and correctly wired it so that if I sent a 'LOW' from my arduino to the transistor, it would allow the current to pass through it.

I have just found that it is actually necessary for my sketch to send a HIGH in order to keep some delays running (im not sure why, but thats what I figured out).

So basically I need to make something that will invert the signal being sent:
IE
If 5v is recieved by new circuitry, 0v is sent AND
If 0v is recieved by new circuitry, 5v is sent.

That may sound a little confusing but im not sure how I could word it better.

Thanks in advance for the help smiley

John
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It would be good if you could post your schematic (just the transistor bit).

You would expect +V to turn an npn transistor on, so it may be that you are not quite wired up right.
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Quote
I have just found that it is actually necessary for my sketch to send a HIGH in order to keep some delays running (im not sure why, but thats what I figured out).

In addition to your hardware schematic, can you explain this comment a bit more?  What the IO pin outputs shouldn't matter.  So the "high" or "low" isn't the actual issue.

As a direct answer, you could simply use an inverter like a classic 7404.
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Thanks for the help both of you, I will Just use a 7404.

John
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