Time and tech wait for none of us. Since this question was asked and answered 7 years ago, the smart trainer has become far more affordable and achieves your needs, at a cost.
These devices fit your bike in one of two ways:
- replace your rear wheel+cassette, and support your weight while riding.
- Hold the bike by the rear axle, and let your existing tyre turn a drum via friction.
In both styles the bike's front wheel remains on the floor but doesn't rotate.
Manufacturers include Tacx, Wahoo, Cycleops, and a bunch of other brands (no brand recommendations are given here).
The difference between these and the indoor trainers of before are that modern trainers will talk to a head unit or laptop or tablet via ANT+ or maybe bluetooth which is wireless.
Separately, indoor trainers like this can be used to complete "virtual rides" like zwift or trainerroad or a bunch of other services. These take your output powers and send them over the internet to servers, that progress you through a level as though you're out riding for real. Extra accessories can change the angle of your bike to simulate up and down hill grades.
Downside is the cost - all of this could cost more than your entire bike, and hundreds of times more than an 11 pound cateye bike computer with a bit of added bell-wire and some heatshrink.
Complete "pain cave" setup example - utter waste of aero-bike