When the wearable technology trend took off a few years ago, brands promised smart glasses, smart clothes, smart everything. We were told that if we could strap it to our bodies and track it, we’d soon be all over it.

Now that the dust has settled and expectations have been tempered by reality, it’s clear that only a few products have really stood out from the rest: most notably Fitbit’s smart watches.

But that doesn’t mean that some of the other ideas...