Protection system for coal home heating , gsm alarm , temperature, pressure

Hello guys, i have an Arduino Uno board and i plan to make an alarm system for my home heating system , which is based on coal ..

I want to install on it a GSM Shield which will call a number in case the pressure or the temperature in the radiator system is too high , or if the carbon monoxide in the room is in a dangerous quantity.

**I looked for the parts on the DX website , maybe you guys can tell me if one of these GSM modules are ok : **

https://www.dx.com/p/sim900a-wireless-extension-module-gsm-gprs-shield-board-antenna-for-arduino-422159#.W-gtqtIzaUk

https://www.dx.com/p/sim900-module-wireless-quad-band-gsm-gprs-shield-expansion-board-for-arduino-red-389873#.W-gtq9IzaUk

https://www.dx.com/p/keyestudio-sim900-gsm-shield-wireless-module-expansion-board-yellow-433518#.W-gtstIzaUk

For the pressure of the water i`m looking at this sensor :

For the water temperature i`m looking at this sensor , will be connected on the outer part of the radioator pipe , and insulated for minimum losses :

https://www.dx.com/p/water-proof-ds18b20-temperature-probe-90cm-142889#.W-gukNIzaUk

For power supply i will use something like this :

A buzzer for local alarm :

Carbon monoxide sensor :

or
https://www.dx.com/p/produino-ccs811-carbon-monoxide-co-vocs-air-quality-numerical-gas-sensor-module-for-arduino-528636#.W-gyoNIzaUk

I will find a box to put all of these toghether .

So let`s recapitulate :
Arduino Uno - in stock
Wires for connections - in stock
GSM SHIELD -SIM900 or similar as per options above - to order
Water pressure sensor : 5V G1/4 0-1.2 MPa Pressure Sensor , Output Voltage: 0.5-4.5V DC -to order
Temperature sensor : DS18B20; Voltage: 3.05.5V; Temperature range:-55'C~+125'C - to order
Power supply : AC 100~240V to DC 9V 2A
Buzzer for local alarm - to order
Carbon monoxide sensor : mq-7 or produino-ccs811

Do i need some additional hardware ?
As this is my first project with Arduino ,any advice will be highly appreciated :smiley: