Can the pro's out there look at this simple PCB to tell if there is a fatal flaw or potential flaw in the layout. The circuit is a 3V battery powered LED driver using an ATtiny85 to conserve power wherever possible and to compensate for declining battery voltage by increasing PWM duty cycle. The LEDs will run at very low current, typically < 1mA total. The PCB is designed to be 2- layer and drawn to scale (63mm x 25mm). The attached image shows an overlay of the two layers. Top layer is a ground plane within the gray shape. The bottom layer is traces only, 1mm thick. Black circles are vias to top ground layer, open circles are vias to the bottom trace layer. Power traces are red, signal traces are green, and gnd traces are black. I am worried about ground loops or signal interferences. PCB board is 1oz copper plate and traces will be hand drawn with sharpie. Any comments appreciated.

 

I am worried about ground loops or signal interferences

Don’t. This is far too simple and slow for any such effects to matter. When you start designing 10MHz+ digital boards then you can worry.

The ground plane is also totally unnecessary.

 

Don’t. This is far too simple and slow for any such effects to matter. When you start designing 10MHz+ digital boards then you can worry.

The ground plane is also totally unnecessary.

Thank you for taking a look and responding

 

The artwork looks OK, but I am confused about the circuit because I do not see an un-switched positive power connection to the ATTINY85 device.only the switched power connection.
Are you able to show us the actual circuit drawing?? So that we can compare it with the PCB layout?? The power positive feed does not look correct.

 

The artwork looks OK, but I am confused about the circuit because I do not see an un-switched positive power connection to the ATTINY85 device.only the switched power connection.
Are you able to show us the actual circuit drawing?? So that we can compare it with the PCB layout?? The power positive feed does not look correct.

There isn't a switch in the circuit. It is powered by connection to a battery supply. Attached is an attempt to use kicad to draw a schematic.

 

That is a quite good schematic A very good start!!

 

Have you ran it through the Electrical rules checker? What is with the conductors running through a component?, open conductors??
You should not need a power line indicator if you have a source identified, i.e. Battery.
A few areas that may not pass the checker.

 

The PCB in post #1 could easily be done with a single-sided PCB. The circuit in post #5 can be done with a double sided PCB .

 

The schematic layout needs a few improvements; also, run it through the electrical rules checker.