Schematic and Board layout
The schematic is broken into sections. The upper left side is things relating to power. The lower left side is power and control to the LED arrays. The middle is power and control to the water pumps. The upper right side is headers and pin assignments for the moisture sensors. The lower right side is the header for the microcontroller.
The Power comes in from the 24V source that is connected to the AC line. From there it is stepped down to 5V by using an LM7805 and stepped down to 12V using a Qunqi step down converter. There is two grounds one for heavy power lines and one for the data lines. This is to reduce noise and give the power lines a clear path to return on.
The LEDs are powered from the 24V input to a BuckPuck regulator that provides a constant 700mA to the LED arrays. They are switched on and off through the microcontroller sending signals to the FQP30N06L MOSFETs. Pull down resistors were added to the MOSFETs to mitigate them potentially switching on when we do not want them to.
The water pumps are run off the 12V supply and controlled by the FQP30N06L MOSFETs. There is again pull down resistors to prevent them turning on when we do not want them to. There is a diode placed in parallel with pumps themselves to protect the MOSFETs from current spikes when they are shut off.
The moisture sensor and microcontroller are powered off the 5V supply. The pin selection was based on the available analog to digital convertors on the microcontroller.
The layout was done in sections. The left is the pumps with their screw terminals and controls. The top is the screw terminal for the 24V in and the step down to 12V. The right is the LEDs with their constant current regulators. The middle is the 5V step down and the headers for the microcontroller and moisture sensors.