Inverting a HIGH signal sent from an arduino

Using Arduino General Electronics
1

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 :slight_smile:

John

2

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.

3

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.

4

Thanks for the help both of you, I will Just use a 7404.

John