I'm trying to build a 3D printer. Unfortunately, I only have a basic understanding of electronics. I have encountered some problems and it would be nice if I could verify that my design is sound before doing any more troubleshooting. I'm mainly worried about signals or power going to the wrong connections, so I have omitted the resistance and capacitance values from my diagram. I haven't had any problems getting the components to work individually (although I haven't been thorough in testing them).
I have included the schematic as an attachment. The wires are colour-coded. Red lines are connected directly to +5V, orange lines to +12V and black lines to a common ground. The rest of the wires are blue. It should be noted that the actual wiring is not represented by this schematic. For example: I have wired the components as if the 5 and 12 volt rails have separate grounds, but the power supply I'm currently using only has one set of ground wires, so they are connected.
Edit: I just noticed that for the 2 channel relay, ground is connected to GND, COM1 and NC2. It should be GND, COM1 and COM2. Please disregard this; it's only a mistake in the schematic.