These sensors operate by using a gyroscope, and an accelerometer to calculate the sudden shift in the G-Force, that you experience when falling. When it detects a fall, a call for help is activated from your medical alert system. (source Wikipedia)
This is not an alert device you purchase all by its self. You can add this to your medical alert system tray, and you can choose between an activated feature on your phone, or a pedant you can wear around your wrist or neck.
This fall detector is one of the best: GreatCall Mobile Lively It provides you with what you need, having a price that is really low, and a performance that is off the grid.
Good sides: Very cheap and an emergency response that is faster than most devices like this on the market
Bad sides: The light on the devices is very bright and draws too much attention
Final assessment: The performance of this device is great and the Lively Mobile is more affordable than almost every device in this category on the market
Price: The pricing of these devices come in three tiers of service options and every one of them is cheap and affordable for everyone that is in dire need of something like this.
Response: The affordability of this system is one of the main things that make it one of the best medical alert systems, but the response performance really puts everything in perspective and makes this an all-around great buy.
System: It has the best speaker, the quality is really high, and while not being so loud, the volume is not needed so greatly because you are never far from the person speaking.