[review] PCB board of arduino experiment board

[mixedoutput]

Hello!
I'm fairly new to PCB design and im looking to improve my skills so I'm hoping to get some useful comments and feedback on this PCB board i've designed.

The board is of a custom made experiment/sensor board that I came up with when I got tired of having to rewire new circuits for every prototype I wanted to do with an Arduino. The idea here is that with this board I will have access to push buttons, LEDs, BT, a buzzer, transistors, displays etc etc without having to rewire these components for each project I want to do.

What i'm looking for is any good tips in what I can change to make an overall better PCB design. I have no formal education in PCB design and therefor i'm self thought through what I've read online and videos I've seen (like pcb design with Dave J).

Also for those wondering... I have purposely chosen against SMD component as I want to use it for educational purpose as well (easier to see big components) and that all things I needed could fit on the board.

The software used was EasyEDA

Here is a link to my project

[rooppoorali]

Hi, have you made a prototype? If so, is that working? If you wish, you can also post your design to  https://www.pcbway.com/project/
for more expert opinions. 

[mariush]

At a brief look over the design ....
Doesn't seem necessary to move the traces on the bottom to flip them as they go to the buttons ... as you can simply number them differently or change order in software.
Both there and with the leds you could use resistor networks to reduce the space used.

10k seems a bit high value on the base of the 2n2222 for me... rather always have that in saturation, so I'd probably half that to 4.7k or even 3.3k
Maybe consider also adding a 10k resistor from base to ground so the transistor won't stay open due to internal capacitance or other reasons.

But may want to consider pre-biased transistors, for example this one has a 4.7k on base, and a 10k from base to ground :
DDTC143ZCA-7-F  : https://www.digikey.com/en/products/detail/diodes-incorporated/DDTC143ZCA-7-F/815239
or
PDTC143ZT,235 : https://www.digikey.com/en/products/detail/nexperia-usa-inc/PDTC143ZT-235/893267

same part, same resistors, 100mA max current, around 80-100 hFe

[mixedoutput]

Hi, have you made a prototype? If so, is that working? If you wish, you can also post your design to  https://www.pcbway.com/project/
for more expert opinions.

Yes I had some made and they worked with some minor fault with a trace I had to cut off. But I updated the pcs design so it should be ok now.
Thanks for the tip I will try that too

[mixedoutput]

Not sure I follow the

Doesn't seem necessary to move the traces on the bottom to flip them as they go to the buttons

For the buttons I think I connected them to certain pins to avoid limiting some functionality from the NANO when buttons are used.

ok thanks for the transistor tips will swap it for 4.7k and the 10k grounding.