Guard Monitor

By Artie DuncansonArtie Duncanson, on 13 Feb 2013 08:16

The guard monitor was constructed as a means of making sure that the security guards do not sleep during their shift. At random intervals of 10-50 minutes the alarm will sound, and the guard must push a button to turn it off, thus confirming that he is awake and at his post.


The alarm housing will be placed within the guard desk, holding the device inside it. The monitor is powered by Power Over Ethernet (POE) inserted into the Arduino Ethernet board. Attached to the Ethernet board is a 65 mm blue LCD screen that will display the amount of time the device has been running for and either confirms or states a failure to push the button that determines if the guard is awake or not. Also joined to the Ethernet board is a 28 mm speaker that emits an alarm at 523 Hz at intervals of 0.50 seconds for the first 30 seconds, then at intervals of 0.25 seconds for the next 30 seconds, and finish with a loud screech for the final 5 seconds. At any point the alarm can be turned off with the push of a button.

The guards will not have to listen to the alarm in the first place if they push the button during the visual cue of a red LED that blinks for 15 seconds prior to the audio cue. A yellow standby LED will remain glowing to show that the program is on and running.

The guard monitors can connect to a web server that logs the activity of the guard monitor and stores it on a webpage developed for storing this data. The recorded activity includes when the device was powered on, if the guard pressed the button prior to the end of the alarm, or if the alarm elapsed without the guard confirming he was on duty by pushing the button. Should a guard fail to push the button before the alarm ends, an email will be notified to a superior notifying that individual that the guard did not confirm his presence at his post.

Project Status

Guard Monitor 1 (located in the main lobby) is installed and powered with a POE switch. This monitor now has the capability of providing status updates to a data log on a web server as well as send email warnings when the alarm button is not pushed within the 80 seconds that the alarm begins ringing.
Guard Monitor 2 (located in the booth in front of The White House) will be updated with the Ethernet capabilities of Guard Monitor 1 as soon as an internet connection is provided to the booth.


Qty Description
1 Arduino Ethernet
1 Push Button
1 I2C LCD Display
1 Red LED
1 Yellow LED
1 Buzzer
1 Housing Case
1 RJ-45 Socket


Guard Alarm Faceplate Cuts


The acrylic faceplate was cut in the above dimensions

Guard Alarm Housing


The Housing Case. Both sides of housing case and the buzzer are lined with aluminum foil. This became necessary because the guard walkie-talkies have been emitting RF signals that jam the electronics within the guard monitors. One side of the foil is taped over with electrical tape to prevent unwanted electrical connections.
Two dimensions of the housing case are given above. The depth of the box is 50mm.



Process Flow


Guard Monitor Process Flow without SD Back up.


Guard Monitor Process Flow with SD Back up.
This occurs when internet connection is not available: the device will store the data (up time and event) in the SD card.
Once internet connection is back, it will send all stored data to the web server.

Change History

Date Description
06/21/2013 v2.0 installed
05/13/2013 Replaced buttons with a more reliable package
03/15/2013 Lined Guard Monitors with aluminum foil
03/04/2013 v1.4: Changed to UNO board with watchdog timer
02/21/2013 v1.3: Added watchdog timer
02/18/2013 v1.2: Removed push button interrupt

Source Code

Name Modified Author
Guard Alarm v2.0-rc 06/21/2013 Kendro
Guard Alarm v1.4-stable 03/04/2013 Kendro
Guard Alarm v1.3-rc 02/21/2013 Kendro
Guard Alarm v1.2-rc 02/18/2013 Kendro
Guard Alarm v1.1-rc 02/18/2013 Kendro

(name files with proper versioning and note stable/unstable release)
File nameFile typeSize
Alum_Foil_Protection2.JPGJPEG image data69.44 kBInfo
Button_Idea.pngPNG image data3.3 kBInfo
Finished (FrontView).JPGJPEG image data107.07 kBInfo
Finished (SideView).JPGJPEG image data101.14 kBInfo
GuardAlarm_01.1-RC.zipZip archive data1.13 MBInfo
GuardAlarm_01.2-RC.zipZip archive data1.13 MBInfo
GuardAlarm_01.3-RC.zipZip archive data41.77 kBInfo
GuardAlarm_01.4Stable.zipZip archive data41.1 kBInfo
GuardAlarm_02.0_RC.zipZip archive data3.58 kBInfo
Guard Alarm Faceplate Cuts.pngPNG image data199.29 kBInfo
Guard Alarm Housing.pngPNG image data179.76 kBInfo
Guard Alarm Schematics.jpgJPEG image data117.91 kBInfo
GuardAlarm_Sideview.JPGJPEG image data247.39 kBInfo
GuardAlarm v2 ProcessFlow.jpgJPEG image data214.46 kBInfo
GuardAlarm w: Sync ProcessFlow.jpgJPEG image data301.52 kBInfo
Guard_Monitor_2_Schematic.pngPNG image data18.37 kBInfo