Hello everyone, I hope I came to the right place for this type of question. Please assume that I am completely ignorant with regards to circuits/electronics (although if you can go into further detail, that would be very helpful in the long run). I am looking to build a simple miniaturized door detection system with the following properties: - System can detect when door is open and when door is closed. - System stores this information in its memory along with the time when the door was open and when it was closed. - One can extract this information and easily read it on a computer. It is critical to keep it as small as possible (roughly the size of a bottlecap). If that is not possible, at what size would it be possible? Also, it can not be connected directly to a computer. What is the best form of energy source? More than one way of accomplishing this would be encouraged. Thanks a lot guys. Looking forward to hearing from you.