GSM and Picaxe 18m2

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imcdiarmid

New Member
Hi everyone,

This is my first post so excuse me if its not in the right place!

I am trying to create a circuit that will text me using a gsm module data that is collected on a picaxe 18m2 chip. I have a adurino wireless GSM module, However if there is a better way of doing it i am quite happy to spend money and use a different gsm module. (Link to module)

I understand that i will need to use AT commands to comunicate with the GSM module how ever where I get stuck is how I connect the picaxe to the module. (The module being rs232)

I am quite proficient in BASIC and this must be about my 10th picaxe project.

Hope someone can help!!

imcdiarmid
 
hippy

hippy

Ex-Staff (retired)
The TC35I module being interfaced to is a 3V3 device and appears to have a 9-way RS232 connector / converter connected. First thing is to study the circuit and work out what needs to be done to use it with a PICAXE.

Actually, first thing would be to get it working with a PC serial connection to prove the board does work. Then I'd add a PICAXE X2 and get that receiving what the module sends back to the PC, then move to getting the PICAXE to send to the module rather than having the PC control it.
 
hippy

hippy

Ex-Staff (retired)
imcdiarmid said:
Any idea how they connected the two together?
Click to expand...
I'd guess 0V and +V to power the board, and from the program SEROUT C.1, T2400 to send to the board; sending seems to be done blind without checking any module response.

One could step frame at a time to see which of the board's pins are used, check what they are in the module's datasheet, look at the screen shot of code for additional clues, check that the reverse engineered circuit of what it could be makes sense.
 
I

imcdiarmid

New Member
I found this online (link)

Would i be right in assuming that i need to use pin 3 and 2 to communicate with the PICAXE Chip?

3 being the input and 2 being the out?
 
G

g6ejd

Senior Member
Looking at the data sheet, the main connector is RS232 so that's +/- 5V - 12V inverted input, converted by a MAx232 device, but the good thing is all data paths head towards TXD0 and RXD0.

What I would do is remove the jumpers on JP2 that link TXD1 and RXD1 to TXD0 and RXD0 respectively, then connect my PICAXE to J6 as follows (youtuber has done the same):

PICAXE
TXD to JP6 RXD0
RXD to JP6 TXD0
GND to JP6 GND
VCC to JP4 VCC (3.3V)

Start talking to the unit with AT commands..., like hippy suggests freeze frame the youtube to see what screen commands he's using to get you going, as they won't be in Danish :)

I'm ordering one :) just right for the winter months as a 'Everest' project (why climb Everest, because it's there :) )

For example, sending a simple SMS might look something like this:

AT ' Check if the modem is alive
AT+CREG? ' Returns 0,1 if the network is registered
AT+CSQ ' Check signal strength. 39 is the highest.
AT+CSMP=1,,0,0 ' Set the modem in to plain text message mode
AT+CMGF=1 ' Use ASCII encoded text messages
AT+CSCA="+64220227672" ' Set the "message center" address. Get this from your network provider.
AT+CMGS="+64xxxxxxxxx" # The destination number to send the SMS to
Your-message-text # Your message text, terminated with a Ctrl+Z or ASCII character 26
 
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