Curcit schematics

Other Hardware General Electronics
1

Could somebody please give me electrical schematics of this curcit

2

Its a bad circuit.

3

MarkT:
Its a bad circuit.

Thank you, but why bad circuit.

4

Because with no button pressed the input will float and give you random values. So basically it is useless for detecting a button press.

5

Grumpy_Mike:
Because with no button pressed the input will float and give you random values. So basically it is useless for detecting a button press.

But I have connected 5 buttons on this way and when none of the buttons is pressed, it is detecting 1024 plus/minus 2 with analogRead(pin).

6

But I have connected 5 buttons on this way and when none of the buttons is pressed, it is detecting 1024 plus/minus 2 with analogRead(pin).

I don't care what you have seen that is not a reliable way to do anything. It might work for now but it is a very unstable situation.

7

The code activates the on-chip pull-up, so its not floating, the problem is
that the on-chip pullup value could be anything from 20k to 50k, so its
useless for reliably identifying the button, an external pull-up resistor is called for.

Of course if you know about CMOS design you'll realise the on-chip
pull-ups are probably not resistors at all, but FETs with long thin channels,
so they will not be stable with supply voltage nor temperature, nor be
linear. The datasheet says minimum 20k, maximum 50k, that's all you
can assume.

8

The code activates the on-chip pull-up,

What code, non was mentioned or posted?

9

detecting 1024 plus/minus 2

1026?

10

Who knows with the invisible code. You shoudn't even see 1024 from the analogue read.

11

There's code in the link where the pic is

12

Not on my iPad ther wasn't.
Don't you just hate having to guess on inadiquite information.

Anyway using the internal pull up is a crap soloution.

13

JimboZA:

detecting 1024 plus/minus 2

1026?

Sorry. Meant 1021 plus/minus 2.

14

logitech:
Could somebody please give me electrical schematics of this

If you have the Fritzing open btw, and click "Schematic" you do get it there. Not quite as nicely laid out as MarkT's, but electrically the same.