Pi to Human Communication

If you have a Pi set up to monitor sensors then you will want to notify someone when things go (potentially) wrong. Assuming your Pi has Internet access (DSL, cable, cellular 3G/4G hotspot modem) you can program it to send out alerts from the Linux Shell, like so:

E-mail:

echo "Warning: Temp below 35F" | mail -s Temp person@some-mail.com

SMS (text message):
echo "Warning: Temp below 35F" | mail cell-phone-number@gateway-name.com

To get the text message to work you have to know what carrier serves the phone number. There's a list at--

  http://www.sweetnam.eu/index.php/List_of_Internet_to_SMS_gateways

Note: In terms of speed, both the e-mail and the text got to me in under 60 seconds. But people are probably more alert to texts.