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Buy DefendLine Kit

DefendLine Kit

DefendLine Kit

DefendLine Kit is a fully assembled and ready to use PCB, it is an excellent solution for anyone from beginners to experienced hobbists, the device can be considered as an inexpensive GSM alarm with potential of sending pictures of a guarded site (the latter option is available for certain mobile phones only). The board works in tandem with a mobile phone or a GSM modem. Apart from GSM guarding function this kit might be used for automation of many different tasks or to serve as a module for more complex systems. For more information please refer to the project’s description: DefendLine project

PLEASE NOTE: The firmware contains user specific settings such as master phone number(s) for sending alerts to and for controlling the device remotely, sensor descriptions, mobile phone commands to interact with its embedded camera etc so you will need an AVR ISP programmer (for instance, USBTinyISP) in order to flash your device. Alternatively, you can provide us with your setting and we can flash it before shipment. In any case the controller is flashed with default settings and tested to make sure it works.


  • Includes Atmel ATmega32 chip with 32k internal flash program memory clocked by 3.6864 MHz crystal;
  • Power supply: 5 Vdc;
  • Four independent input lines for alarm sensors (PIR sensors, etc);
  • Two output lines to relay board;
  • Serial interface for communication with mobile phone/GSM modem/RS232 converter;
  • RTC (32768 kHz) crystal;
  • Standard AVR ISP 10-pin connector for in-circuit flashing;
  • Extension connector with 10 I/O lines;
  • Backup power supply and software driven main power failure detection;
  • Two buttons for toggling modes;
  • Two LEDs (red and green) to indicate states;
  • Open source firmware unlocks literally unlimited potential of this kit;

It includes:

  • 1 x fully assembled and tested PCB;
  • 1 x power jack;
  • 1 x modem connector;
  • 1 x alarm sensors connector;
  • 1 x CD with firmware source code and documentation;

$32 USD for item plus $8 USD for flat shipping