• Automotive
• Aftermarket
• 12V
• Car Alarm
• CAN
• KLINE
• J1850 VPW
• 1-Wire
• ADC
• GSM
• Telit GL868-Dual
• SMS
• SMS Menu
• Voice Menu
• DTMF
• RTC
• Requirements Engineering
• Hardware Development
• Schematics Design
• PCB Design
• Altium Designer
• Reverse Engineering
• Protocol Reverse Engineering
• Firmware Development
• STM32
• C
• C99
• ChibiOS
• USB
• SPI
• I2S
• UART
• Speex
• Serial Port Multiplexer
• 3GPP TS 27.010

Overview

This project is a GSM-based aftermarket car alarm system designed for vehicle security, remote control, and status monitoring.

A standout feature of this system is its integrated support for parking heater control and diagnostics (Webasto or Eberspächer), making it especially useful in cold climates where remote heater activation and scheduling add comfort and convenience. The system can even be configured to place a notification call to the owner once the cabin temperature reaches the desired level.

The system offers a versatile DTMF-based voice menu, SMS interface, and hardware support for standalone operation even when the original heater timer/control unit is absent.

Key Features

• CAN interface for integration with the vehicle
• Dual LIN/J1850 VPW interfaces to communicate with parking heater
  • Allows in-line installation between the heater and its stock timer/control unit, enhancing functionality without interfering with original operation
• External LED and button for standalone heater control (when stock timer/control unit is absent)
• 4x universal analog inputs
• 4x digital inputs
• 1x high-side power output (up to 3A)
• 3x low-side relay control outputs (up to 150mA each)
• 1-Wire interface for external temperature sensor
• External microphone input
• 12V vehicle power supply
• Fully operational in -40 … +85 °C ambient temperatures

My Contribution to the Project

• System architecture design
• Schematics and PCB design in Altium Designer
• Reverse engineering of parking heater communication protocols
• Device bring-up and validation
• Full firmware development in C99 using ChibiOS, including:
  • USB-enabled bootloader
  • 1-Wire temperature sensor driver
  • Telit GL868-Dual GSM modem driver
  • Serial port multiplexer (3GPP TS 27.010) driver
  • I2S bus driver implemented via generic SPI peripheral
  • Speex codec integration for compressed voice playback
  • DTMF voice menu system
  • SMS command interface
  • Parking heater control and diagnostic
  • Low-Power modes, including wake-up via CAN, LIN and

Product Images