Title: SIM908 gps coordinate reading Post by: Ichan on May 18, 2012, 10:42:52 22:42 Hi,
I have problem with Simcom SIM908 where it shows my home more than 20km missed on google maps. Anyone can show me the light? -ichan Title: Re: SIM908 gps coordinate reading Post by: Ichan on May 21, 2012, 06:54:22 18:54 The error is in me :-[, I miss interpret the coordinate output of the SIM908 - now the green arrow of google map pointing exactly on the place where I put the antenna, I can say it is in 1 - 2 meter range :P.
Sharing something about SIM908:
-ichan Title: Re: SIM908 gps coordinate reading Post by: falcon _bd on May 25, 2012, 07:40:15 19:40 Can you share a schematic of sim908 , PIC 3.3v mcu power supply and antenna`s.
Title: Re: SIM908 gps coordinate reading Post by: Ichan on May 26, 2012, 08:27:48 08:27 If there is no other voltage level on the system then the best way is to use mcu at 2.8V level. Mine has some device with 5V operating voltage, I choose mcu with 5V tolerant I/O operated at 3.3V and use resistor divider for output to the SIM908.
Attached is the mcu and SIM908 part stripped from the original schematic, antenna directly connected to RF connector at the top of the module. Edit: On the schematic VSAT is 5V and VGSM is 4.2V, while the VMCU is 3V3. -ichan |