SMS Controlled Switch using a raspberry pi

This code interacts with a SIM7600 4g module using AT commands over the serial port. It uses the module to send and receive text messages for the purpose of controlling one more more switches. I use this to turn a preheater on and off for my airplane, but it probably has other uses too :-) It started out for a SIM900 module which stopped working when TMobile shut down their 2g network. The AT commands are pretty much the same for both though.

Setup

On a raspian minimal image, install the following modules:

apt install python3
apt install python3-serial
apt install python3-rpi.gpio

If you want a 1-wire temp sensor to be detected, add the following lines to /etc/modules

w1-gpio
w1-therm

Commands

1. On Command

• Syntax:
  On <switchID> <time> <duration>
  Description: Schedules <switchID> to turn on in the future at <time> for <duration> minutes.

  Example:
  On 1 18:30 15
  (Turns switch 1 on at 18:30 for 15 minutes.)

• Syntax:
  On <switchID> <duration>
  Description: Turns <switchID> on immediately for <duration> minutes.

  Example:
  On 2 10
  (Turns switch 2 on now for 10 minutes.)

2. Off Command

• Syntax:
  Off <switchID>
  Description: Turns <switchID> off.

  Example:
  Off 1
  (Turns switch 1 off.)

• Syntax:
  Off
  Description: Turns off all switches.

  Example:
  Off
  (Turns all switches off.)

3. Temp Command

• Syntax:
  Temp
  Description: Returns the current temperature as measured by the external DS18B probe.

4. Status Command

• Syntax:
  Status
  Description: Returns the status of the switches, including whether they are on or scheduled to turn on.