Designing a Low cost GSM/GPS tracker – SMS Tracking Demo – Part 3

Cost of Assembling:

I had to pay Rs.1600 for getting two of the boards assembled. I could have done the assembling myself but most of the parts are in QFN and 0402 packages which are difficult to solder so i had to send them out for reflow soldering. Boards were assembled in 4 days time and sent back, because the assembling was done with manual process without stencil as i insisted on getting it done without stencil to save cost. Manual process without stencil makes it slow and takes time. 

Here is how the boards look : 

The boards were designed after lot of reviews so luckily no major design problems were present and software worked flawlessly. 

Boards ready for testing : 

Motion Detection alert : 

The first basic testing what i did is the testing of motion sensor, which is the major new addition in VALTRACK-V2 compared to VALTRACK-V1. What i did is, I configured the accelerometer to interrupt the processor whenever the motion in any axis crosses certain threshold value. So whenever there is an interrupt the sensor alerts the MCU and the MCU sends an SMS telling a motion was detected at this particular location. This can be used to prevent vehicle theft whenever there is a movement detected. 

SMS Tracking test : 

The next test done was testing if the device can respond with its location in a SMS if asked. So i programmed it to detect a certain command/password string (00000 in this case) and get the location information from GPS, and reply back to the asking number, which VALTRACK-V2 successfully did. 

One more thing what i did is, If there is no GPS signal available for 2 minutes, after the user asks for location information, then it sends the previous known location value which it had saved in its EEPROM memory when the signal was available earlier. 

There are some mechanical problems i need to fix in next iteration of the design which i have explained in the video below. Do have a look at it and stay tuned for more updates. 🙂

Also see : 

• Designing a Low cost GSM/GPS tracker – Update – PCB’s arrived – Part 2
• Designing a Low cost GSM/GPS tracker – Introduction – Part 1
• SIMCOM got acquired by UBLOX ! – Is it a GOOD news or BAD news
• Don’t use SIM900,SIM908,SIM800,SIM808 modules in USA (2G sunset)