I have an idea for a safety coffin which is one of those graves with the bell on top in case someone is buried alive by mistake. I am thinking about how to make the bell ring. I know there are those with more electrical knowledge so I am looking for ideas. In general I came up with a couple of different ways. I could imagine putting a magnet on the bell and then using an electromagnet to move it. I know it is possible to even make an electromagnet but I am not sure it would have enough power to move the bell. I have also thought about a door lock actuator. My plan would be to use a simple PIR to activate it. I think a very short interval would be fine since I just want it to fire ring the bell and reset. If people set it off several times in a row it just seems like the person is more desperate. That means I had no plans for a controller. One question I had is if I can simply hook up the PIR to a 12V circuit and when it detects movement it closes the circuit. I must admit it seems almost too simple. I just wanted those with more knowledge to tell me if I am missing anything.