Presence Detection System

Sensor detects the presence of an object and signals gateway to notify user by beep or email.

SENSOR
- An ultrasonic sensor detects an object within a range of 0.5 to 2m for 4s and then signals.
- The sensor will send the signal by bluetooth to a gateway up to 300m away.
- The sensor is battery powered for 1 month and can be charged by 5v solar panel or adapter.

GATEWAY
- A gateway powered by AC will beep, post, and email notifications.
- When power is applied to gateway it:
  - beeps ~1s.
  - fast blinks while trying to connect to wifi for 10s.
  - if it does not connect to wifi, it fast blinks and tries to connect WPS to wifi for 30s.
  - if it does not connect WPS, it goes into AP mode for 60s where a client can connect to it.
  - if it connects to wifi, it stays connected to the AP for 30s in which clients can connect.
  - when finished connecting to wifi it listens for sensor messages on bluetooth.
  - a client can connect to the IP address of the gateway to bring up the cofiguration screens.
  - the gateway will blink each time a sensor message is received to indicating all is working.

APP
- An Android app can be used to view the object distance from sensor.
- the Scan app can be setup to look for Presence sensor messages.
- the message will show the distance of the object from the sensor.
- when no object is present, it should say >600cm.