Hardware Reference
In-Depth Information
The resistors “ R p ” in Figure 4.9 have values of 3.3 kΩ. V DD1 and V DD2 values can be found in
the Arduino board. It should be noted that any N-Channel Enhancement Mode Vertical DMOS
FET can be used if it operates on the following ranges:
Gate threshold voltage min 0.1 V to max 2 V
On resistance max 100 Ω at I D of 3 mA and V GS of 2.5 V
Input capacitance max of 100 pF at V DS of 1 V and V GS of 0 V
Switching times of max 50 ns
Allowed drain current of 10 mA or higher.
The two power resistors are turned on and of by the Arduino that controls a relay to the
24 A power supply. Connect the power resistors as shown in Figure 4.10 . Be sure to connect
the relay to Arduino Digital Pin 48 and the power resistors to the Normally Opened pin on the
relay.
FIGURE 4.10 Wiring diagram for the power resistors.
Similar to the power resistors, the humidifier is connected to the Arduino through a relay
as shown in Figure 4.11 . The humidifier AC plug cable has two wires, and one must be split.
Connect one end of the split to the Normally Opened pin on the relay and the other to the com-
mon pin. Set the humidifier knob to medium and connect to a wall plug. Connect the relay to
Arduino Digital Pin 39 .
 
Search WWH ::




Custom Search