I need an arduino programmer- GAS ALARM

Hi All I work in a laboratory, we use a whole bunch of different gasses fed from control panels. The control panels came with NO/NC pressure switches (5V), unfortunately there was no budget for the accompanying alarms. We built some using just LED's and relays. I would like to use an arduino as the controller for the alarm systems with the following functions: - Control LED's: When the contact is closed (Normal State) a green LED is constantly on indicating normal status, when the contact is open the green LED turns off while a pair of RED LED's blink and a buzzer sounds indicating fault status - When contact open (fault status), an SMS is sent to programmed phone numbers stating "LOW LEVEL- GAS X". I would like to use the SIM800L EVB shield to perform this function. - I would like to interface the 1.5" RGB OLED module with the system. When all contacts are closed then the screen must indicate in green "normal status". When a contact is open then the screen must indicate "LOW LEVEL- GAS X" in red. If multiple contacts are open then the screen should cycle through the different gas [login to view URL] let me know if there is a better option for the screen. - The alarm must have a 'test' button which lights up all LED's (green solid, red blinking) and activates the buzzer. An SMS must be sent stating "TEST". This is to test all components. - The alarm must have a mute button which mutes the buzzer for a period of seconds The system must be able to handle up to 10 pressure switches all working through a single arduino mega, sim800L module and OLED screen. SEE PICTURES OF ALARM LAYOUT. Please feel free to recommend more suitable components. I require the code to be developed and physically tested, please provide a wiring diagram as well. Thank you