A Simple Door Monitoring System with HANA XS and Raspberry Pi

Intro

I have built a simple door sensor with SAP HANA and Raspberry Pi to monitor the door-opening events. The wireless door sensor is a magnetic gap sensor that will send the RF 433 Mhz signal to the receiver when someone open the door. The Raspberry Pi with the receiver within the range listens for the incoming signal from the sensor. Once the signal is detected, the Raspberry Pi will send the ODATA http post request  to the HANA server. You can monitor the events status from the web app (backend).

If you never heard of Raspberry Pi, you may refer to its website at http://www.raspberrypi.org/ . Building the receiver will not be covered in this blog. Please refer to this blog to build it: Adding 433 to your Raspberry Pi | Ninja Blocks

HTTP POST Command: Curl

On the Raspberry Pi, there is a command line tool in Linux to post the http request: curl with the JSON data: body.json.

if (mySwitch.getReceivedValue() == 13981149 ) {

                system(“curl -H ‘Content-Type: application/json’ –data @/home/pi/433Utils/RPi_utils/body.json http://hana2.vm.cld.sr:8000/rpi/sensor/service/RPISensor.xsodata/RpiSensor

          }

The body.json contains the current timestamp, date and STATUS = Open. The timestamp and date will be auto-populated by the insert procedure on the HANA XS side.

{“STIMESTAMP”:”\/Date(0000000000000)\/”,”SDATE”:”\/Date(0000000000000)\/”,”STATUS”:”Open”}

To run the receiver, just type sudo ./RFSniffer on the Raspberry Pi command prompt. This command listens to the incoming signal from the sensor and sends the http post ODATA request to HANA XS. On the HANA XS side, the insert procedure will update the HANA table.

Project Structure: Key Components

The structure and explanation is pretty much the same as in my earlier blog here: http://scn.sap.com/community/developer-center/hana/blog/2014/07/07/real-time-gps-tracker-using-sap-hana-xs-sapui5-cordova-geolocation-plugin-and-odata

Let’s focus here on the key components:

• The RpiSensor table to store the status of the door events:

• The  XSODATA:
  

• The InsertRowRPISensor procedure:
  

• And also the web app backend SAPUI5 to view the information:
  

A complete source code can be found on GitHub: ferrygun/HANADoorSensor · GitHub

Summary

You could make an internet of things by combining the power of SAP HANA and the micro-computer/controller like the Raspberry Pi/Arduino with other sensors (e.g,. GPS, temperature/humidity, contact sensors, etc) and create a dashboard to present the status of the sensors.

Thanks for reading my blog. I hope you enjoy it.