Oh yeah, absolutely, but given the number of those showing up on eBay, they're widely available.
Plus, the support expectations for "something we got cheap off eBay" and "something we got from the one and only Mad Max" are quite a bit different.
Heh, thank you, I think, Ed. Yes, the cheap off eBay means you are on your own. Getting it from me means I would rather throw myself off a bridge than have somebody go through life with something from me that didn't work.
All kidding aside...
Those modules you are looking at on eBay use the same sort of ASK messaging protocol I use (that's where I got the idea).
But...
Some things you really should think about before going with those... Trust me, I went through this same process, including
testing out modules like that.
1. Up/down buttons for speed? Really?? Ewwwww....
2. That coily wire thing for the antenna. Yeah... don't bet on that for very good range. If you only need to go about 10 feet, maybe.
But you'd be much better off with a true 1/4 wavelength dipole (yes, a simple 2-wire "rabbit ears" thing). Notice how
the transmitter comes with a telescoping pull-out old-school antenna. That's because a straight length of wire works
better than the coily coil. If you read their "fine print" in the eBay ad, you'll notice that they say their claim for distance
is only valid if you use a straight wire for the antenna. (In case your wondering, the "straight wire" has to be 17.3 cm long
for the 433 MHz type, and 23.7 cm for 315 MHz.) So you should mount the receivers high up in the room out of the path of
human bodies, and solder on a length of wire for a real antenna.
3. Interference:
All your hand-helds will be operating on one frequency (315 MHz in your case), or at best
two (you can buy these in 315 or 433 MHz). If you operate two or more at the same time, they will interfere with each other.
You won't accidentally control the wrong receiver with the wrong transmitter, but neither will get its commands through, and
your train will just keep happily doing whatever it was doing. That can be really annoying when 2 or 3 operators are holding
down the "speed down button" and the transmitter is streaming out successive "slow down" commands.
4. Direction? Since the direction is pushbutton, you have no indication of how your direction is set. At least a mini toggle
would make it intuitive to just flip the toggle to reverse your train. With those pushbuttons, people will be
pushing "one and then the other one" because who's going to remember which button was which way?
5. Current?
It doesn't say how much current those can handle, but looking at the tiny surface-mount regulator I see on
the receiver board, it can't be much. Maybe 2 engines' worth in N Scale?
6. Do the users of this thing operate DCC equipped engines? These modules you are looking at surely use
PWM for their motor control, so you may want to do some testing on a smattering of DCC-equipped engines to make sure
they don't freak out on the PWM.
7. A final note on this part, " of those showing up on eBay, they're widely available."
Don't bet on any of these being able to interoperate with each other. Many of them don't that I tested. If a hand-held fails,
you likely will have to just toss out your receivers and transmitters and buy a whole new set of them.
I'm not trying to throw a wet rag on your idea. Truly, I'm not. But like I said, I messed around with modules like that,
and these issues are much more of a pain than it might seem when you actually try to operate a train with them.
