GrayBOX - Accident Detection and Theft Protection System




About: HI, I am a Mechatronics engineer, currently doing Masters in Robotics engineering...But most of all I am a MAKER.

GrayBOX is a device which protects you and your vehicle*.

This device will be mounted on your vehicle* and will perform some tasks automatically to save you and your vehicle*.

GrayBOX contains a SIM card so you can communicate with it via text message(SMS only, no watsapp ;-)).

Tasks performed by this device are :

  1. Accident detection : If you are in a road accident while driving your vehicle* then GrayBOX will automatically send help message to predefined numbers(as many numbers you store in the GrayBOX) with your GPS location.
  2. Theft protection : When you are going to a place where rate of vehicle theft is high, then at such location you can keep GrayBOX in alert mode by sending it "ALERT" command** via text message. In alert mode, if your vehicle* is moved then GrayBOX will send you help message. To cancel the alert mode, just send "RELAX" command**.
  3. Stopping theft execution : If by any chance thief stole your vehicle* then also you can stop him/her. To do so, send a command** "STOP" and GrayBOX will disconnect the power supplied to the spark plug of the engine and vehicle* will stop. To again engage the spark plug send "RUN" command**.
  4. Location acquisition : you can also track your vehicle* by sending "?" (question mark) command** to the GrayBOX and in return it will reply you with its GPS location.
  5. Communication with user : GrayBOX also communicate with owner of the vehicle*.

*This project is made keeping two wheelers in mind, but with little changes in code it can also be applied to four wheelers.

**Commands should be in the form of *command#.

Ex. - *ALERT#, *STOP# etc.

NOTE - This project is completely working but not yet tested in the field.

.....More videos coming soon.....

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Step 1: Tools and Materials


  1. Microcontroller board (Arduino compatible) or Arduino UNO.
  2. GSM module
  3. GPS module
  4. Accelerometer sensor
  5. SIM card (Activated and with some balance)
  6. Relay switch
  7. LCD
  8. Fasteners
  9. connecting wires
  10. Battery (12v)


  1. Soldering iron (If making custom microcontroller board and relay switch module)
  2. FTDI board (If making custom microcontroller board)
  3. Screw driver
  4. wire stripper
  5. Multimeter
  6. Glue gun
  7. Power supply
  8. A computer

Link from where I bought my components -

Step 2: Making Custom Microcontroller Board

Note - If you are using Arduino board or any other Arduino compatible board then jump to step 4.

  1. Components required
    • Atmega328 with Arduino bootloader
    • 28 pin IC base for Atmega328
    • IN4007 diode
    • 470uf capacitor
    • 10uf capacitor
    • 7805 voltage regulator
    • 22pf paper capacitor (Quantity - 2)
    • 16 MHz Crystal oscillator
    • 100nf capacitor
    • 1k resistor (Quantity - 2)
    • 10k resistor
    • LED
    • Berg strip
    • Jumper wires
  2. Download the schematic and PCB file and make PCB.
  3. Drill with 1 mm drill bit for soldering components at their respective places.
  4. Solder each component carefully.

If everything goes as planned then your microcontroller board is ready.

NOTE - Use expressPCB to open .pcb file

Step 3: Connect GSM, GPS Module, Accelerometer Sensor and LCD to Microcontroller Board

Connect GSM, GPS module and Accelerometer sensor as shown in images. If you are using Arduino board then connect as following.

Accelerometer sensor:

  • x-pin to A5
  • y-pin to A4
  • z-pin to A3
  • vcc to +5v/3v3
  • GND to GND

GPS Module :

I connected GPS module's serial pins (Tx and Rx) to software serial pins of the microcontroller board. So you can change it in the code according to your need.

  • Tx-pin to 5
  • Rx-pin to 6
  • vcc to +5v/3v3
  • GND to GND

GSM Module :

  • Rx-pin to Tx
  • Tx-pin to Rx
  • Vinterface-pin to +5v
  • Vin-pin to +5v
  • GND to GND


LCD is only for our convenience, otherwise not needed.

  • rs-pin to 2
  • rw-pin to 3
  • enable-pin to 4
  • D4-pin to 10
  • D5-pin to 11
  • D6-pin to 12
  • D7-pin to 13

Step 4: Final Assembly and Programming

  • Assemble the different modules as I did for making GrayBOX compact.
  • Insert SIM card in GSM module.
  • Connect FTDI to the microcontroller board (only if using custom microcontroller board, otherwise directly upload the code to arduino board) and upload the given code.

In case of suggestion or doubt feel free to contact. You are always welcome :-)

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    50 Discussions


    Question 1 year ago on Step 1

    I am using GSM 800C and GPS NEO,. code will change? If change what kind of change.

    1 answer

    Answer 8 months ago

    I don't think that code will change.


    2 years ago

    Hi.. Nice concept... i am working on Adxl345 and had some doubts so was searching about it and thus landed on your proj page. I would like to know which accelerometer have you used here? Adxl335 or Adxl345 or Adxl377 or ...?


    Reply 2 years ago

    It's already uploaded. Download Greybox_final.ino, that's the code you need.


    Reply 2 years ago

    can u send the program of this project to my mail. my mail is


    2 years ago

    Can you please send me the relay circuit for this progm?


    2 years ago

    Can you show me the relay circuit?

    Winston 8

    3 years ago

    Hello,will you ever upgrade the project for example adding a lcd screen?

    Abhijith giridhar

    3 years ago

    Do you have any working video that explains how GRAYBOX works.the included video just specifies the different parts required to assemble it.

    1 reply
    sw4pAbhijith giridhar

    Reply 3 years ago

    Yes I do...I have a video which completely explains the working of GrayBOX. I am going to post it soon.


    3 years ago

    I have an idea for this. Instead of cutting the power instantly after the "Stop" command, you could have it wait for the vehicle to stop and have it (somehow, if it's an automatic) put it into park, cut the engine, and put the hazards on to warn others. :)

    3 replies

    Reply 3 years ago

    if I wait for thief to stop the vehicle then it will be hard to catch him...


    Reply 3 years ago

    But if there's some kind of error/glitch/mishap the owner could be the victim. =T


    Reply 3 years ago

    What kind of glitch??

    the only thing its doing is cutting the power supply to the spark plug of the engine, which happens to most of the vehicle when carbon is accumulated in the spark plug.