Hi, I am planning to control multiple solenoids with the Arduino Mega board. I read the tutorial on controlling a single solenoid with an Arduino and reviewed the diagram posted in the playground. Attached is a diagram I worked up to help myself design/think about a system that would control multiple solenoids in a series. Each solenoid would cycle on for (at most) 10 minutes, and off for 120 minutes. The specs for the system are:
-Arduino Mega -Solenoids: 2-way direct acting, NC, 12VDC, drawing around 250mA -Resistors: 1k -Transistors: TIP102
I would appreciate any feedback on the following:
1) Will the system as designed work (with the correct programming of course) to switch each solenoid on/off one-by-one in a series? Am I missing any component or using the incorrect type of resistors/transistors? Is the wiring correct? Can it be simplified?
2) Is a heat sink necessary for the transistors?
2) What type of wire should I use? Is 20 AWG hookup wire sufficient?
3) Can I continue to add solenoids with this configuration up to the maximum number of output pins on the board?
I talked with an engineer at the solenoid manufacturer and he said I would not need to use flyback diodes with this model of solenoid.
This will be my first time working with a microcontroller and I do not have any formal training with electrical wiring or circuit design, so I apologize in advance for any glaring errors/omissions. Thank you for your assistance.