Saturday, April 6, 2013

Home Alarm System using Raspberry Pi, Netduino Plus and ATtiny85 (HomeAlarmPlusPi project)

Latest update: Friday, November 8, 2013

This is an open source home alarm monitoring system using Raspberry PiNetduino Plus, ATtiny 85 and a typical home alarm system. This implementation could be used in conjunction with the PC5010 Digital Security Controls (DSC) PowerSeries Security System control panel and sensors.  Tested with Netduino Plus 1 running .NET Micro Framework 4.2 (QFE1 or QFE2) and Raspberry Pi Model A running Debian GNU/Linux 7.0 (wheezy).

Previous Implementation
When I first started HomeAlarmPlus on February 2012 my intent was to have a simple home alarm monitoring system and learn more about microcontrollers. As the knowledge kept growing, also the complexity of the circuitry, system and requirements. Then Raspberry Pi complemented the existing project by using full capability of Apache Web server. This involved massive code changes to the original project reflected in HomeAlarmPlusPi.

Use full capabilities of Raspberry Pi and Netduino Plus to monitor home alarm system and report any sensor/motion detector activities via email (using Simple Mail Transfer Protocol (SMTP)), local web server, notifications (using PushingBox) and Pachube (now Cosm).

Programming Languages and Web Development

On Netduino Plus

Netduino Plus 1
  • C# for Netduino Plus
  • HTML for Web Server with Cascading Style Sheets (CSS)
  • JavaScript for Web Server

On Raspberry Pi
Raspberry Pi with enclosure and cardboard on top with 12 VDC micro fan.
  • HTML5
  • PHP
  • Java Script
  • JSON
  • jQuery
  • Weather Underground API
  • Python (under development: use of GPIO)

On ATtiny85
Arduino “in-system programmer” (ISP) shield ATtiny programmer. 
This code contains information related to a typical home alarm systems.  Please, be aware that this procedure may void any warranty.  Any alarm system of any type may be compromised deliberately or may fail to operate as expected for a variety of reasons.

The author, Gilberto García, is not liable for any System Failures such as: inadequate installation,  criminal knowledge, access by intruders, power failure, failure of replaceable batteries, compromise of Radio Frequency (Wireless) devices, system users, smoke detectors, motion detectors, warning devices (sirens, bells, horns), telephone lines, insufficient time, component failure, inadequate testing, security and insurance (property or life insurance).

One last thing:

Required Hardware
  • Raspberry Pi Model A or B
  • Netduino Plus
  • ATtiny85 (ATTINY85-20PU).
  • SD Memory Card 4 GB or above (Class 10 preferred).
  • 5V 1A (1000mA) USB port power supply.
  • Micro SD Card 2 GB
  • WiFi(802.11b/g/n) USB Module [1], [2] or [3]
  • SD Card Adapter
  • 3mm green Light Emitting Diode(LED) per alarm zone and motion detector.
  • 330 ohm for each LED.
  • NPN Transistor
  • 10k ohm variable resistor
  • 1k ohm resistor for transistor's base.
  • 5600 ohm resistor per alarm zone and motion detector.
  • Schottky diode per alarm zone.  Schottky diode should have low forward voltage drop like the SBR10U40CT.
  • ScrewShield (Proto-Screwshield (Wingshield) kit from [1] or [2]).
  • WiFi connection using any WiFi Internet Adapter. Tested on Netgear WNCE3001 and IOGEAR GWU627.
  • Basic 16x2 Character LCD [1] or others [2].
  • DPDT switch [1] or others [2] for LCD voltage selection.
  • 74HC595 Shift Register

Optional Hardware
  • Panel Mount LED (Green LED with Holder)

  • Mini Buzzer (3VDC)

  • USB Ruggedized / Waterproof Panel Connector (RR-211300-30)
  • Debugging Alarm using external USB.  There is no need to open the alarm panel.

  • RF Receiver Toggle Type to arm/disarm [1].
  • USB 2.0 Cable, Type A Male to A Male (10 Feet or above). Used to access the Netduino Plusboard on the alarm panel.
  • 200 Watts / 350 VA UPS (APC BE350G UPS System or similar).
  • Push button for external reset.
  • Arduino Proto Shield R3. More space for additional components.[1] or others [2], [3].
  • Low-profile microSD card adapter for Raspberry Pi [1].
  • Raspberry Pi case [1] or others [2]
  • In-line power switch for 2.1mm barrel jack [1] or [2].
  • Raspberry Pi heat sink set [1].
  • 12 VDC Micro fan to cool down Raspberry Pi [1].

Modified Raspberry Pi case with fan

For HomeAlarmPlus and HomeAlarmPlus Pi the conditional symbol ALARM_DEBUG enables alarm debug on Visual Studio. To enable debugging on Visual Studio just right click AlarmByZones project, select properties, select Build tab and add ALARM_DEBUG under "Conditional compilation symbols".
Debug setup
More debugging capabilities will be implemented for Raspberry Pi and ATtiny85.

The following Fritzing diagram shows how the Netduino plus, LEDs and the alarm zones (or motion detector) are wired. Compared from previous implementation(HomeAlarmPlus) I added ATtiny85 in order to reduce threads in the Netduino Plus 1. By doing this I saved 2 KB of RAM and have more code space.

HomeAlarmPlus Pi connection diagram Rev I.

HomeAlarmPlus Pi circuitry
HomeAlarmPlus Pi circuitry details
Keep in mind that one or more zone consist of the following:
a) 1 Normally Open contact and 1 Normally closed contact with End Of Line (EOL) resistor.
b) Double EOL circuit, 1 Normally closed contact with 5.6kohm EOL resistor and Schottky diode.  This will bring the protection needed for the Netduino or Arduino.
c) Each ground zone should be connected to the  ProtoScrewShield GND.

Netduino/ProtoScrewShield Pin
A0 Zone #1
A1 Zone #2
A2 Zone #3
A3 Zone #4
A4 Sensor #1 [Motion Detector]
D0 xBee RX
D2 LED Zone #1
D3 LED Zone #2
D4 LED Zone #3
D5 LED Zone #4
D6 LED Sensor #1 [Motion Detector]
D7 RF Toggle Pin (RF Receiver)
D8 Power ATtiny85
D9 Burglar Alarm or Mini Buzzer
D10, D11 and D13 Shift register LCD

Web server options on Netduino Plus
/Root page desktop format.
/openOpen last file on SD card.
/sdcardList files on SD card.
/suSuper user. Shows additional options.
/pachubeShows Pachube activity per zone/Datastream.
/aboutApplication credits and version.[Desktop version]
/about-mobileApplication credits and version.[Mobile version]
/delete-confirmDelete last file on SD card [confirm window].
/delete-lastDelete last file on SD card [no confirm window].
/diagDisplays available memory on Netduino and forces to clear the garbage collector.[Desktop version]
/diag-mobileDisplays available memory on Netduino and forces to clear the garbage collector.[Mobile version]
/dateGets date time from Raspberry Pi.
/mobileRoot page mobile format.

HomeAlarmPlus [Desktop version]
HomeAlarmPlus [Mobile version]

Web server options on Raspberry Pi
/Root page desktop format.
/index.phpRoot page desktop format.
/weather.htmlWeather data from Wunderground.[Desktop version]
/mobileRoot page mobile format.
/mobile/index.phpRoot page mobile format.
/references.htmProject link references.
/aboutApplication credits and version.
/NetduinoPlus/setNetduinoTimer.phpSetup/Update Netduino Plus time/date.

HomeAlarmPlus Pi web server [Desktop version]
HomeAlarmPlus Pi webserver [Mobile version]

HomeAlarmPlus Pi [Apple mobile screenshot]

Software Architecture

HomeAlarmPlus Pi Software Architecture

Detailed Software Architecture

Final Product
Final Product showing mobile access, Raspberry Pi, Netduino Plus 1, custom shield for Netduino and Home Alarm Panel

Under Development
  • Web interface for tablet based devices. [Testing, not released]
  • Cameras with integrated motion sensor and night vision. Camera should be integrated with Raspberry Pi GPIO.
  • More debugging capabilities for Raspberry Pi and ATtiny85.
  • Explore additional notification options like IFTTT. [Done. Released July 17, 2013]

Code Repository and Documentation

HomeAlarmPlus Pi just initializing

HomeAlarmPlus Pi Initializing and Running


  1. Great work.... thanks for share.... i will like to see whith the ITTT....

    1. Thank you for you comments Eduardo. I have been updating code in repository.

    2. Eduardo, as promised, I added Pushover notification on the Raspberry Pi side. It is on PHP (index.php). You can create recipes on IFTTT and add Pushover.

  2. Security is the primary factor for everyone to safe guard their family and business. This blog will be helpful for those who needs to know about Home security System and its advantages.

  3. Hi, great work.
    Do you connect the PIR sensors to the old system as well as your new circuit? If yes, how do you do this?

    1. Maknet, thank you for your interest in HomeAlarmPlus Pi. I used the following link as a reference for the old circuit ( I have not implemented PIR yet for the new circuit. Thank you again.

  4. Hi Gilberto,
    I am not sure why used the 2 micro-controllers though the RB-Pi already has a processor in it ?


    1. Baba, for this project I use the Raspberry Pi as web server and Netduino Plus for the alarm/sensors. Raspberry Pi does not have ADC so you need to use MCP3008 or MCP3424. I could consolidate in one platform but in security systems it is better to have redundant monitoring. Thanks.

  5. If you change your event listeners from "onClick" to "touchstart", the button down-state will appear ~300ms earlier. 'onClick' waits 300ms for a double click.

  6. Hello,

    I've created a similar project using Arduino.

    A PC is used for external control (WebUi)

    More info here :
    I’ve created an alarm system based on Arduino.

    I’m also communicating with a PC using USB (serial over usb)

    More info :

  7. Hello there! I must tell you the blog post is really good. It is very informative. Yes off course security is must in house.I really appreciate and keep writing..
    Thank you..

  8. Hi, Gilberto... Thanks for sharing this; I've bookmarked it (meaning I hope it stays up for a while) and intend to give it a whirl in a month or so. Meanwhile, I just have to tell you that I got a kick out of your robo-spammers. (I get them, too...)

    - Jim

  9. Hallo, can you explain me why you used Netduino Plus and not Arduino?

    Kr Guido

    1. Thanks for your question. There are many reasons but the main one is that I use C# daily. You will find out that concurrency and multithreading on Arduino is not as easy as in Netduino boards. Another reason is that I do not need to buy an Ethernet shield since it is integrated in Netduino Plus.

  10. I really appreciate yOu posting this very imformative blog. I just hate to see your blog comments becoming an advertising column. Maybe you can use your c# programming skills to filter them out? Excellent alarm though, the best I've seen on the web so far

  11. Very nice information .....thanks for sharing....

  12. This comment has been removed by a blog administrator.

  13. Nice it seems to be good post... It will get readers engagement on the article since readres engagement plays an vital role in every blog.. i am expecting more updated posts from your hands.
    Home Automation in Chennai
    smart home in Chennai
    Home security in Chennai
    Burglar alarm in Chennai
    Door sensors Chennai

  14. I got great information from this blog.It is very informative..
    commercial security cameras