I was curious about gathering information about my surroundings, my weight, fat mass, and all the other indicators which makes me tick without going to get it measured outside of my home. About a year ago I snapped a picture at Best Buy about this scale which transmits your data to an app on the IPhone. I recently purchased one. There are three different companies who offer such device. I opted for Withings, it gives you a reading for weight, fat mass, heart rate, and air quality in your home. This scale is able to recognize up to 8 users. Everyone can have their own user profile and access it independently.
Don't get too excited if the scale tells you that you weigh less then you anticipate, it might be off. Try it several times during the morning hours, the last reading might be the accurate one.