Need expert advice on Microcontroller & GSM for specific project

[tajiknomi]

Hi everyone,
I'm making a security system which will have a GSM module in it. I need an advice on MCU to which i can connect both GSM module and i can use some its I/O pins to external circuit also. So i have searched for it and i find Arduino with its GSM shield but there are two problems with it.

1) Arduino GSM shield is expensive.
2) When its GSM shield is connected to Arduino , it leaves no I/O pins for me to drive external circuit.

Can i use PIC MCU for this purpose ? it will be cheap. Using GSM features (like sending/receiving msgs) using PIC maynot be as simple as in Arduino (i don't know yet, i just guess it)
Is their any other platform (Inexpensive & efficient) for my purpose ? Is there any better way to do this ?

Any advice/suggestions will be helpful.
thanks

 

[Nigel Goodwin]

PIC's work fine with GSM modules, as does any processor - essentially you're just sending and receiving serial ASCII data.

Some of the big advantages of PIC's is their low cost, huge number of built-in peripherals, and very low external component count.

As for your 2) - the GSM shield only uses a small number of pins, you can still use the rest as you wish.

 

[Diver300]

I use PICs with GSM modules. It is certainly easiest to use the UART in the PIC. The process of sending data through a GSM module has several stages in it. You will need the datasheet for the protocol of the GSM module. For debugging, it can be very helpful to monitor the communication between the GSM module and the PIC with a terminal emulator on a PC.

GSM modules need a really good power supply, as the current that they take is in short pulses when transmitting. If your aerial is anywhere near the rest of your circuit, the radio frequency interference from the aerial can affect your circuit.

 

[tajiknomi]

Thanks for your kind replies.

1) I have worked on PIC18F a year ago for a small project. But its my first time to use GSM module, therefor i will need to study (for the GSM-PIC interfacing) before i get my hands on the project. Material can be links/books which you people can kindly suggest (any) will be helpful.

2) Which PIC family/model should i choose for my task, I just have to use GSM and External alarm circuit to drive. How many pins will be reserved by the GSM module ?

3)

You will need the datasheet for the protocol of the GSM module

Which GSM module is best suited for PIC ?

 

[Nigel Goodwin]

Thanks for your kind replies.

1) I have worked on PIC18F a year ago for a small project. But its my first time to use GSM module, therefor i will need to study (for the GSM-PIC interfacing) before i get my hands on the project. Material can be links/books which you people can kindly suggest (any) will be helpful.

2) Which PIC family/model should i choose for my task, I just have to use GSM and External alarm circuit to drive. How many pins will be reserved by the GSM module ?

You only need two, the RXD and TXD serial port pins.

Personally I used the 16F1827, which is an enhanced 14 bit core - a specifically useful function of these devices is that you can access GPR's sequentially (I used it as a buffer to store a complete received text message in).

3)
Which GSM module is best suited for PIC ?

It should make little difference - I used a couple of different ones during development, with the final one just a chip on the same PCB as the PIC.

 

[Wp100]

Although Arduino based think you will find this site a wealth of starter information .


There also this project with C++ code based on Tronixstuffs tutorial.
https://www.eevblog.com/forum/oshw/arduino-sms-temperature-alarm-controller-for-fish-tanks-etc/

Been looking to covert that SMS code to add to my existing Pic18 project, but like Nigel am still an Assembly coder rather than C.

What do you code in ?

 

[NorthGuy]

I would also suggest PIC16F1* series (PIC12F1* if you need less pins). They're really good for a small application like yours. There's a huge variety of them. You can select them by the number of pins, the memory you need, and by the form factor - you can get DIP packages for prototyping, or you can get tiny QFN packages - you would probably need few dozens of them to cover a penny. Any PIC with hardware UART module will be fine.

 

[tajiknomi]

Thanks for your suggestions.
I'm now thinking about PIC16F. I will need a suitable and less costly GSM module now.

 

[Wp100]

Be aware of / don't make the mistake I did and buy one of the cheaper Ebay Sim900A modules instead of the Ardunio style Sim900 shields.

The Sim900A is programmed to work only on certain far east networks.
It can be made to run in the rest of the world, but it has to be reprogrammed with the Sim900 firmware; did it myself from the PC with a serial link, but perhaps not a job you want to do while still learning or a board / program to prove the download worked ok.

Lots of other gsm module out there to choose from, though they do cost a bit more.

 

[tajiknomi]

Lots of other gsm module out there to choose from, though they do cost a bit more.

Can you suggest me a GSM module which has reasonable price (with no overheads of firmware etc) and its also available in Proteus platform ?

 

[Wp100]

Can you suggest me a GSM module which has reasonable price (with no overheads of firmware etc) and its also available in Proteus platform ?

I cannot, have only used that Sim 900 module, but sure others will be able to suggest some.
Might be helpful if you put your country , as supplies may vary from area to area.

 

[be80be]

I have the sim900 and in the US it's not as easy to get sim's for it now I know why they sold it so cheap. I've used 3 sim's and none will let me send text. Got to find a sim card that is 2G and text and data only I thought I could use a data only card but it blocks the text. These things don't use much mine is for a arduino but it's only using 3 pins RX TX and one to turn it on.

 

[tajiknomi]

I found SIM900 MINI, i kinda like its structure and price https://digipak.org/zencart/index.php?main_page=product_info&cPath=5&products_id=197