Help on schematic - Right or Wrong

Hello, just would like to know if my schematic is right ?


Seems fine.

Thank You

That is not a schematic diagram. It is a "Fritzing diagram", which is usually not very useful, and they are often misleading or wrong.

You should be aware that on some breadboards the power/ground tracks along the top and bottom are disconnected across the middle. If yours is like that, the buttons may not work as you expect. Add a jumper if you are not sure, or check continuity with a multimeter.

1 Like

Are those pulldown resistors really 220 Ohms? That is very low resistance for a pulldown. Usually 10K or so.

A better way to wire switches is to wire the switch to ground and an input set to pinMode INPUT_PULLUP to use the internal (built in) pullup resistors. Then there is no need for an external resistors nor is there extra wires with 5V running to the switches. The input will read HIGH when the switch is not pressed and LOW when the switch is pressed. Adjust your code accordingly.

It is recommended that one wire to diagonal terminals of those kind of switches to avoid the possibility of a short.


You are right I should use 10K

Supplying power is usually needed....
As the design has no output from eventual calculations out of inputs it looks like a "do nothing"....

It appears to be functionally correct.

Comment on the connections:

It doesn't matter here as there are not higher current devices, but in general it is good to physically keep all the grounds close to each other, as well as the power.

Comment on the design:
It doesn't really matter, however you could have connected the pushbuttons between the Arduino pin and ground, enabled the internal pullup function on those pins. This would eliminate the resistor.
The resistor you show should be in the order of 5k to 20k ohms.

Your diagram will work IF the buttons are inserted correctly. If the buttons are rotated 90 degrees, they will not work, but you cannot tell that on a child's Fritzing or TinkerCad picture.