SIM808 interfacing SD Card to download files over 200kb using FTP

So, I’m using here SIM808 module with FTP to download files and store it to SD card as small chunks.
Any resources or documentation will be really appreciated.

Hello and welcome!

Which module are you using? Does it have a SD slot already or are you planning on adding one?

Hi Viedana!

Thank you for getting back.
So, right now I’m using this module:https://robokits.co.in/wireless-solutions/gsm-gprs/sim808-gsm-gprs-gps-modem?gclid=CjwKCAiAj-_xBRBjEiwAmRbqYmmg8_9EiGX5UggMi4_1_Q08nC7_5rJzWL7_5yMGwZcoXu_iPiYq-BoCOPcQAvD_BwE

But, In future I’m planning to use this module:
https://www.amazon.in/Elementz-Engineers-Guild-Pvt-Ltd/dp/B01N2U777W/ref=sr_1_4?keywords=sim808&qid=1580371947&sr=8-4

So, with the first one I want to interface one SD card using this Adapter:
https://robokits.co.in/arduino/arduino-accessories/microsd-card-adapter-module-for-arduino-with-spi-interface?gclid=CjwKCAiAj-_xBRBjEiwAmRbqYsRit8WmTytO1TguInHLsjqL9-jBZEOlJStkZU6Dmt0x_uqRhlMmJRoCJQoQAvD_BwE

Ok, according to the SIMCOM documentation for the SIM808, the SD functionality doesn’t come by default and you’ll have to talk to them for a custom firmware. And in any case, it seems that neither board has the SD cards pins exposed. The easiest and cheapest solution I would recommend you is to use an Arduino compatible micro-controller or board to interface between the SIM808 and the SD card.

Some considerations to make it easier for you:

  • Use a 3.3v Arduino, as both the boards and the SD card module you’ve linked are compatible with this voltage.
  • You might need to bypass the 3.3v voltage regulator present in the SD card module, because it requires a 5v power supply and this would just give unnecessary complications.

That was really helpful suggestion. I will tell whole scenario. I am planning to use SIM808 with STM32, both run at 3.3V level.
So, are you suggesting to transfer files over serial from 808 to Arduino and then store it to in SD card. Later I’m planning to use additional flash chip instead of SD card.
P.s.: Can you please tell me where can I request for Custom Firmware and how much time it might take, if you know.

Excellent, I have no personal experience with the STM32, but I think it would work flawlessly for this.

Yes, I believe it would be the easiest way to approach this.

I’d recommend this only if the main concern is to reduce cost, and maybe a little bit of size. Otherwise, by going with a flash chip you loose in maintainability and versatility while the durability might be the same.

Sorry, I’ve never contacted SIMCOM directly. If I have to guess, I’ll check on their website first for any contact info. As far as I know, they are really approachable and open to dialog.