Pull up and pull down confusion

[cobragra]

Hi, I'm fairly inexperienced so please forgive the simple question but I've searched Google and these forums and can't find a definitive answer to this.

I have a FreeNove starter kit and running through the tutorials. On the attached image it shows the difference in a pull up and pull down circuit.

What I am confused about, is that on the two schematics shown, both appear to me to be schematically identical when the switches are closed, and yet one claims to read high and the other low.

Please can someone explain this?

Thanks
Graham

[srnet]

What do the pins read when each switch is open ?

[jim-p]

You are not confused, the second one makes no sense.

The first schematic is the correct way to detect button presses

[JohnLincoln]

The second schematic is wrong.

I've edited that second picture to show you what it should be like:

[Delta_G]

And take note that the Arduino has built in pull-up resistors. If you use pinMode INPUT_PULLUP then you don't need any external resistors to use a switch.

[JohnLincoln]

cobragra,

There is a link to download the documentation for that starter kit at https://freenove.com/tutorial.

If you download it from:
https://github.com/Freenove/Freenove_Starter_Kit/archive/master.zip
it looks as though the error has now been corrected.

(good job I checked before sending them an email).

[GolamMostafa]

Examples:
1. External Pull-down

Figure-1:

2. Internal Pull-up

Figure-2:

3. External Pull-up

Figure-3:

[cobragra]

Thanks. My kit is actually this one, which looks like it still has the documentation error: GitHub - Freenove/Freenove_Ultimate_Starter_Kit: Apply to FNK0017, FNK0018