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Monitored home alarm

November 01, 2023 by Malcolm McGrath

An arduino uno runs an alarm monitor program that allows input from either a 4x3 touch panel or from the base/rover cell phone. The monitor program looks for a closed intruder circuit and raises an alarm to the base/rover cell phone.


Emerald wireless smoke detector

5v 9v 12v UPS


. The Arduino and the base cell phone are powered by a UPS, loss of mains power does not effect the alarm system.

. The Arduino alarm program is armed by either the 4x3 touch keypad or by the base or rover program.

. The alarm can be set on instantly or be set on with a delay of 2 minutes to enable egress without then having to enable the alarm after securing the perimeter.

. A triggered alarm can be disabled from the touch panel by entering a PIN or by entering the same PIN on either the base or rover cell phone.

. Arduino monitors multiple circuits and tells the base program by BT if a circuit is closed, the circuits are open when armed, and breach when the circuit is closed, the circuits are created with pairs from a cat5 cable and use micro switches with levers.

. Password can be changed on both base and rover independently, setting the password on the base will also reset the password on the Arduino.

. A breach occurs when either one of the monitored circuits is closed or a panic button is pressed.

. On breach the alarm program triggers a piezo buzzer and sends a text message by BT to the base cell, the base cell receives that text and in turn sends a text to the rover, the rover announces that a breach has occurred an opens the alarm program on the cell phone.

. On breach the base station continually plays a mp3 file . The rover plays a short breach mp3 file.

. The base and rover program is a MIT App Inventor app, the program can be configured to either base or rover.

. There are two outputs for LED indicators for alarm status, one is to the alarm panel with the 4x3 keypad the other is to a remote LED i.e. above the front door ( so that you know not to open it while the alarm is enabled)

On the rover phone Automate for Android is used to create a script to process incoming messages. Messages received by the rover initiated from the base cause an alarm on the phone and the rover app to be started. The rover app does not need to be running all the time on the rover.

Not yet implemented:

. Detect the triggering of smoke alarm and trigger a fire event on the base and rover

. Increase the potential monitored circuits to 24 ( 3 x PCF8574 on a separate circuit board )

. Multiple rovers

. Local group (i.e. neighbour notification )


Why use wired circuits? I did not want to have to worry about batteries or power to the remote switches, the base has a UPS and the system will work pretty much without maintenance.

Control panel for the alarm: 2x16 LED display an indicator light 3x4 touch panel the components are mounted on/in a panel cut from a nylon kitchen cutting board Indicator light: on the alarm is set, off the alarm is off flashing there is a breach


Malcolm McGrath

Been retired for 10 years but like to fiddle with my Arduino's.

Average programmer, terrible tech.


  • Avatar
    Malcolm McGrath

    Been retired for 10 years but like to fiddle with my Arduino's.<br/> <br/> Average programmer, terrible tech.

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