One of the advantages of having a gym partner is that he/she can help you check your form while working out to minimize the risk of injury and maximize the effectiveness of the exercise.
Many people choose or are forced to train alone though, so they have to rely on mirrors to check their own form. This is not always possible though as some exercises might require you to be turned away from the mirror and even if you can see the mirror, it's easy to miss bad posture while training.
The idea is to create a smart mirror that can check on your form for you, warn you when you are doing a movement incorrectly and even potentially tape your workout for revision later.
I found a paper that has suggested developing a similar product but it never went past the planning stage. Smart mirrors like Care OS Poseidon Mirror exist already with other features like games, magnifying, facial recognition and virtual try on for clothes but nothing has been created for the fitness industry yet.
Tru Posture's Smart Shirt also has the technology to monitor your posture, but focuses only on your spine and shoulders and needs to be accessed via their app.
The idea is to have a mirror that knows movements, so that it can check if you are performing the exercises correctly. By configuring the mirror to yourself, it should be able to compare your movements to a database of good, clean performances and notify you of any deviations. If it is able to do this, it would be able to count your reps as an added feature as well.
Mirror Home Gym is simply a large screen that displays workouts for you to follow and it does not track your movement at all. Tempo seems to be the only product that checks your posture by using infrared scans, but it also does not act as a mirror. My idea resembles a normal mirror much closer than a television screen and would be simpler to program.