Experiment with GPRS

This article documents attempts to connect a Raspberry Pi to an MQTT server through a GPRS Modem.

We have selected initially the Waveshare GPRS Hat... https://www.robotshop.com/en/gsm-gprsgnssbluetooth-hat-raspberry-pi.html

Potential problem - this card requires pressing a button to power up. This could be a big problem as we don't want to have to press any buttons to get it working after connecting power.

This is a low cost modem (around £25) that should be capable of functions required.

It is intended to combine this with a low cost SIM data card designed for MQTT purposes, from Thingstream... https://thingstream.io/products/thingstream-iot-sim/

Documents:

• Wiki
• Product Page
• Manual on Module

https://www.raspberrypi.org/forums/viewtopic.php?t=123659

Components

• 

  HIU with RS485 output

• 

  RPi Zero + Node-HIU SD Card + GSM Modem + IoT SIM Card (with aerials for GSM, GPRS & Bluetooh)

• 

  RPi Zero Mainboard

• 

  RS485 Interface

• 

  GSM Modem

• 

  24-5vdc Power Regulator

Thingstream

https://thingstream.io/product/thingstream-iot-sim/

First successful text messaging

• https://www.youtube.com/watch?v=1sLGkFlAvgk&list=PLXm_y6rrNVJcWnuuyelAG1HQx9w_Yepdr&index=2
• https://www.youtube.com/watch?v=CNFl8amKHPw&list=PLXm_y6rrNVJcWnuuyelAG1HQx9w_Yepdr&index=3 WORKED !

AT
OK

AT+COPS?
+COPS: 0,0,"T-Mobile"

OK
AT+CBC
+CBC: 0,78,4027

OK
AT+CMGF=1
OK
AT+CMGS="07557342430"
> hello
>
+CMGS: 212

OK

Ctrl + A then Ctrl + D quits screen.

GPRS

https://www.youtube.com/watch?v=iLRSoYWue2U&index=4&list=PLXm_y6rrNVJcWnuuyelAG1HQx9w_Yepdr

AT+CSTT="everywhere","eesecure","secure"
OK

AT+CIICR 
OK

AT+CIFSR 
ip_address

AT+CIPSTART="TCP","heatweb.co.uk",80
OK

PPP

https://www.waveshare.com/wiki/SIM868_PPP_Dail-up_Networking

This is how to create an internet connection.