First of all, the layout, the board is not big, the area of 45mm*75mm, because the back side is the battery box, so the elements are basically in the TOP layer.
At first, due to the influence of previous remote control, the board was made narrow and long, DB9 and power source were placed at the top (front) end, and 4 buttons were placed at the bottom.
Lights and codes are placed above the KEY.
This interface is all on the left side, and the volume of the device is usually placed on the narrow side (the left and right sides of the above layout), so as to make the board weld better and balance it out.
The button is down on the right, and people usually use their right hand, so it's here.
The dial is on the left side of the button and the lamp is above the button.
All the other interfaces are at the top.
Some of the unit circuits can be grouped together in the layout, which can reduce the amount of wire running and make the board cleaner.
For example, the LED button and the corresponding up - pull resistance, do not scatter open.
And when it comes to wiring.
First, the signal line, then the power line.
The board is relatively simple, press this to come to be no problem commonly.
Walk a class of signal lines side by side.
The control line of better LED lights should be four parallel lines.
2. The line coming out of MCU (with more feet) should not punch holes near the pin pad.
That's not good for the line behind it.
But this time I made this mistake.
3. The 0603 pin can be wired between the package pin, but generally do not. If it is the signal of 9V on DB9, please avoid or reverse it.
This layout was violated this time, but it has been corrected.
4. Walk the line in parallel and next to each other, which will leave more space for the line.