This specific code runs for ultrasonic sensor and gives high alert if there is motion beyond 20cm. Additionally if we use RFID tag ultrasonic sensor stops functioning and gives authorized access to make motion.

Dependencies:   MFRC522

Revision:
0:c7eacabfa681
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+++ b/CONTRIBUTING.md	Mon Dec 16 17:44:49 2019 +0000
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+# Contributing to Mbed OS
+
+Mbed OS is an open-source, device software platform for the Internet of Things. Contributions are an important part of the platform, and our goal is to make it as simple as possible to become a contributor.
+
+To encourage productive collaboration, as well as robust, consistent and maintainable code, we have a set of guidelines for [contributing to Mbed OS](https://os.mbed.com/docs/mbed-os/latest/contributing/index.html).