The Maduino Zero SIM808 GPS Tracker is an IOT (Internet of things) Solution based on the 32-bit Atmel’s SAMD21 MCU and GPRS/GSM GPS module SIM808. It intergrates a micro Controller ATSAMD21G18, GRRS/GSM module SIM808, which is the upgrade version of SIM900, power management and storage, to make the SIM808 GPS Tracker ready for IOT projects such as smart-home, outdoor monitoring, shared bicycle, etc. The Marduino Zero SIM808 GPS Tracker based on the Arduino, users can program it with Arduino IDE, which is very easy especially for the none-programmers.
This is the V3.4 version, Note that to ensure the module starts up right, a lipo battery is needed to power up the Maduino Zero SIM808 GPS tracker V3.4.
Quick Spec
AT Input Voltage: 3.4-4.2V
Microcontroller: ATSAMD21G18, 32-Bit ARM Cortex M0+
Clock Speed: 48 MHz
Micro SIM connector
Integrated Power Control System
AT command interface with “auto baud” detection Quad-band: 850/900/1800/1900Mz
Send and receive GPRS data (TCP/IP, HTTP, etc.)
GPS L1 C/A code
22 tracking /66 acquisition channels
Tracking: -165 dBm
Cold starts: -148 dBm
Time-To-First-Fix：Cold starts-32s (typ.), Hot starts-1s (typ.)，Warm starts-5s (typ.)
The Pro Mini has proven to be a suitable solution. The board is very small and has more than enough specs to control the GSM/GPRS module while also sending data to a remote server via TCP.
The Pro Mini requires an FTDI programmer since there is no USB port on the board.
FTDI programmers pin out relative to the Pro MiniPro Mini ( ATMEL MEGA328P MU1039 )
A quick solder up to test the circuit (had issues with power sharing between GSM module and ATTINY85)
My first attempt to build a small circuit which controls a relay to an alarm speaker was a failure. Contrary to popular belief failure in electronics projects is quite common and I would argue that it is of paramount need if you want to learn anything.
Surprisingly my failure was in using the ATTINY85 instead a Pro Mini, Uno or Mega. Some problems I had were:
Not enough RAM to hold all my variables (I had to scrounge 😢)
Very limited FLASH memory.
GSM module interferes with the ATTINY’s 5v power source when connected using the same source with no filtering.
In a later project I created a reliably working solution with the Pro Mini as the brains.
My goal was to create a small circuit which uses the ATTINY85 as the brains. It uses the A6-GSM-Module to receive SMS’s, phone calls and sends TCP data. Finally it has a 5v relay which will switch on/off an alarm speaker. The theory is that when I’m on the farm in the fields and not near the house, I have the option of remotely starting an audio alarm at will. This should be a deterrent to potential criminals.
I made an easier to debug testing circuit with exposed copper traces (Same issues)
After making an easier to debug circuit I tried to get the ATTINY85 to work happily with the GSM module. This was going to be a bit complicated and I suspect I would have to isolate power between the ATTINY85 and the GSM module. This would require more components and the board is already looking cramped. A much easier solution is to use the Pro Mini instead of the ATTINY85.
