I am starting a new project using 2 air solenoids to control pneumatic air cylinders. The solenoids require more voltage than the Arduino can supply so I wll use an external power supply to power them, but the relays I currently have require 5V to activate and the Arduino pins only supply 3.3v.
I found the video Tutorial: How to design a transistor circuit that controls low-power devices - YouTube today that makes me wonder if I can simply use a transistor to switch the solenoids. In fact, the video shows several power switching options, but I’m just a starting hobbyist so not sure what the best option is for my project and I’m starting to get overwhelmed. I know the solenoid requires 12V, but the following other number are also printed on it:
- 12V DC
- 2.5 VA
Additionally, the online specs http://www.voguepc.com/upfiles/120513033202.pdf indicate it will operate with +/- 10% of rated voltage and that the power consumption is 3w.
- Am I better of using a relay, NPN transistor or something else, and why?
- If the answer is to use the NPN transistor, what size transistors do I require on the switching power and do I need a diode on the collector side to protect against voltage buildup?
- If the answer is a relay, do I need to purchase relays that will active from the 3.3v the Ardunio pins will supply, or is there another option to amplify the 3.3v to operate my existing relays?