What board (w/ Arduino) should I use to control 5VDC to smoke unit?

Hi George -

Since the motors and heaters take a lot of current, the Arduino can't control them directly. You can use the Arduino to turn on a transistor, that in turn controls the motor or heater.

You could use discrete transistors, or a chip like the ULN2003A or ULN2803A that packages 7 or 8 Darlington transistors into a single IC, along with base resistors and flyback diodes. You should figure out how much current the motors and heaters will draw, to be sure the transistors can handle the load. One transistor would be needed to control each motor or each heater.

Any Arduino will work fine for this application, since the Arduino only needs to supply enough current to turn on the transistors.  You need one Arduino digital output for each transistor, but nearly every Arduino has at least 8 output pins that you could use.

For small projects like this I like to use the Pololu A-Star 328PB Micro. To program this Arduino you need a USB-TTL adapter;  the more expensive 32U4 Micro has USB built-in. Comparable products are the Sparkfun Pro Mini and Pro Micro. There are plenty of cheaper clones around, but I'd start with products that offer full support from the supplier.

From your description it sounds like you will have a source of 5V DC power, which can be used to power these Arduino boards through their VCC pins. They can also be powered with a DC source up to 12V or so, via their on-board regulators.

Let me know what questions you have!

George:

A relay module would work too. Although if the currents are low, and isolation is not required, then a simple transistor seems like a more elegant solution.

The ULN2803A is good to about 0.5A per output, with 2.5A total at any one time. A discrete transistor like the TIP120 should be good to about 5A.