Almost - don't connect Aref to +5, just a cap to Gnd. It has internal connection to +5, or +3.3, under software control.
Connect pin 7 to 20.
This where a view of the schematic comes in handy.
If you can do a ground pour, or ground fill, or whatever the program you are using calls it, then you can delete the all over the place ground traces and just connect those pins to the ground plane instead. That will make for quieter signals too.
You have room on the board - I would add a diode in parallel with the reset resistor - anode to the reset pin, cathode to +5. This will keep any spikes that occur from making the chip think its going into High Voltage programming mode (and look liket its just hung up to you). 1N4158 type of diode is sufficient.
Looks like you have 2 regulators? Would recommend caps on the 2nd regulator also. 1uF on input, 0.1uF on the output.
Do you have any plans to add pin names (D0, D1, etc) or part names (C1, C2, etc)? That really helps to make the boards look sharp.
Looks pretty good. Trace for pin 20 is kinda thin compared to the rest. Maybe indicates it has not been routed yet?
Schematic turned out pretty good.
Still recommend a diode across R4 for reasons described before. At least put pads in for it if you don't want to install it to start.
I was kinda afraid of modifying the schematics because first i suck at understanding them... but i think i can understand them by now.
About the thin wire, yes i didnt double click so it was a rastnest line instead of being a wire (corrected now)
diode just like that?
None that I see.
I still recommend a ground pour - that will save on etching material also as you only etch enough to isolate the pads & traces, and not clear out whole big sections of the board.
Is this what you are saying ?
i've choose GND as a ground seed and then did Ground Fill
i cant understand how it works and how i'm gonna etch my pcb like this
That's the idea, but it seems to have the ground on one side of the board and the traces on the other, hence the 2 different colors (yellow-ish gnd, and reddish traces); from the jumpers you showed earlier I figured you were making a single sided board. Try it again with the ground pour on the same side as the traces. What you want is to just have the copper removed from next to the traces and around the pins, you can see where that took place arond the pads already.
Yes the board is single-sided... i really cant do that ground pour with fritzing.
i'm trying moving the wires to the other side of board and doing copper fill to see if this is what you mean.
Ok, copper fill then. Have that and the traces on the same side of the board.
Then you end up like this, where the white is the copper that is removed and the red is the copper that is left.
This is for a surface mount board. You probably want everything on the bottom layer for easier soldering of pins to pads.
That's exactly what I mean! That looks pretty good.
Last thing I would recommend is making the 90 degree corners on traces into a couple of 45 degree corners.
This is important in home etching because often the inside corner can be over-etched leaving the resulting corner trace on the thin side.
Some nice attempts. Tinning makes a massive difference to the solderbility.
A little while ago, I came across an article, but can't find it right now. It used a CD printer to print the etch resist and the silk screen layers directly onto the board, pretty nifty. I think they used a simple two-edged jig to ensure registration. They were using a non-FeCl etch too (which is a pain to recycle and stains everything around).
Use good quality PCB drill bits and a drill post (dremel et al make them). If you allow the drill to self-centre, drilling is quite easy and can look good. Self centring requires the pad hole to be quite small). The technique is to visually align the drill/work, then as the drill nears the work, allow the work to move, and the hole in the pad will align with the drill, hold firmly and press through. Obviously works with smaller boards. Use of backing board leaves a good finish.