Searching https://home.howstuffworks.com/question238.htm
Knowing that "some grocery stores have automatic door openers that use a very simple form of radar to detect when someone passes near the door. The box above the door sends out a burst of microwave radio energy and waits for the reflected energy to bounce back. When a person moves into the field of microwave energy, it changes the amount of reflected energy or the time it takes for the reflection to arrive, and the box opens the door."
I would like to build such simple radar, for intruder alarm.
I know there is other method like IR, PIR, ultasonic, but I like to try this radar technology for learning/fun.
Anybody can give me some hint on the TX/RX radio circuit?
What freq range is using?
Thank you.
Knowing that "some grocery stores have automatic door openers that use a very simple form of radar to detect when someone passes near the door. The box above the door sends out a burst of microwave radio energy and waits for the reflected energy to bounce back. When a person moves into the field of microwave energy, it changes the amount of reflected energy or the time it takes for the reflection to arrive, and the box opens the door."
I would like to build such simple radar, for intruder alarm.
I know there is other method like IR, PIR, ultasonic, but I like to try this radar technology for learning/fun.
Anybody can give me some hint on the TX/RX radio circuit?
What freq range is using?
Thank you.