Hi to everyone,
I’m trying to design a board with different sensors(humidity, pressure,
GPS) that send all the data using the SIM868 and we want to send all the information via GPRS.
I’m having a big problem. When I send the PIN with the command AT+CPIN the board turns off. I have tested a lot of things and I can’t find the source of this problem.
At the beginning I thought it could be a power supply problem, but after a few test I think that the problem is in other site, because I tested it using a power supply with 4V and 2A (the maximum that accept the SIM868) directly to the SIM and the problem was still there.
Now I’m using 5V and 2A to power the board, and I have a regulator that limite the voltage to 4V. I have all the capacitors that are said in the design document of SIM868.
Following some posts of this page I have upgrade the firmware (because I thought it could be the problem) but it wasn’t.
I thought I had a problem with the antenna because if I insert the sim’s PIN without the antenna the board don’t turn off as quickly as when I use the antenna. If I connect the antenna it turns off in less than 8 seconds. I’ve tried to use a SIM without PIN code security, but the board is restarting all the time. I think that the problem is not the pin code but the connectivity with the server. I have tried with 2 different antennas so now I think that the problem should be in other place.
Tell me if I’m wrong but it isn’t necessary to configure anything before introducing the PIN number is it? The SIM868 answer all of the AT commands that I have tried but only turns off with the AT+CPIN command.
I can’t do anything without this command so please, if anyone has any idea of what is happening help me
Any idea is welcomed, even if it sounds crazy.
Thank you in advance and I hope you can help me.