I am looking to build a simple proximity circuit but i am not sure where to start or what methods would work best.
General Idea/goal:
circuit 1 is carried by the user and sends (wireless) signal to circuit 2 (in pulses approximately 10 seconds apart to save battery life) circuit 2 is in the object that the user does not want to loose receives signal and (pings) response to circuit 1 in a similar manner (but preferably without need of a power source) If (ping) is not received by circuit 1 it will give a signal to the user. *signal does not need to go farther than 4 ft*
I am pretty sure this is the basic principal behind RFID but i am asking if this can be simplified to something i could make at home without buying or finding a RFID tag or tag reader
*It does not have to work off radio, i do not know but maybe some form of electromagnetism could be used. Any ideas are welcome. If you have one Please contribute*
General Idea/goal:
circuit 1 is carried by the user and sends (wireless) signal to circuit 2 (in pulses approximately 10 seconds apart to save battery life) circuit 2 is in the object that the user does not want to loose receives signal and (pings) response to circuit 1 in a similar manner (but preferably without need of a power source) If (ping) is not received by circuit 1 it will give a signal to the user. *signal does not need to go farther than 4 ft*
I am pretty sure this is the basic principal behind RFID but i am asking if this can be simplified to something i could make at home without buying or finding a RFID tag or tag reader
*It does not have to work off radio, i do not know but maybe some form of electromagnetism could be used. Any ideas are welcome. If you have one Please contribute*