I'm building a small morse code chip as a fun project, and I have a question about sending pulses over a wire. I was planning on using some speaker wire to connect a few of these PCBs over a somewhat long distance. I can buy packs of speaker wire that are either 16 or 24 gauge, and either 100 or 50 feet or even longer (longer is preferable). One wire is for data, the other is ground. The load at the other end is another microcontroller (I might have multiple branches with more than one of an identical microcontroller circuit).
The power source I was going to use for this circuit is a CR2032 coin cell battery. It can provide more than enough current to power all of the components in my circuit.
Before I go about buying a bunch of components, I want to get some advice on a few things. Firstly, I want to have the option of sending square wave pulses from a microcontroller. Would it be better to use a transistor to switch the connection to the wire on and off, or would it be adequate to simply send pulses directly from the microcontroller pin? I'm also unsure about my power source. I know that the CR2032 coin cell battery can deliver only very small amounts of current, so would it be best to upgrade to something like a LiPoly? Or would the coin cell be sufficient to send pulses across the wire? Additionally, are these power sources even adequate for such a large wire? I would ideally like to avoid having to worry about voltages over 5V and alternating current, which I know propagates down a wire more efficiently.
My last question is simply about range. What kind of theoretical maximum wire length could I send data across given the batteries I described? If I remember correctly larger diameter wires have less resistance, but since the 24 gauge wire is cheaper I would like to purchase that if it won't affect the range by too large of an amount.
Thanks for your help!