Is it possible to run a line from my gas water heater (up stairs) to the garage to connect to a gas dryer?
Avoid anything made in China, as difficult as that may seem. Metallic plumbing is always subject to corrosion, and the fact your house's plumbing has survived almost 80 years without leaking is remarkable. If you are building an addition look into a product called PEX (Shark Bite). This urethane composite tubing will never corrode, split, crack, expands if it freezes, very easy to install and will last relatively forever. It's UPC approved and once it's installed you'll never have to worry about it.
Some types of sensors we use are: (1) rate-of rise (detects the rate of temperature rise in a closed space) (2) fusible link (link melts at certain temperature) (3) bi-metal sensor, or thermostat (closes a contact at a certain temperature) (4) fire-eye (detects light in a certain spectrum range) (5) smoke detectors, or ionization units, that detect smoke particulate in the air. (6) infrared detectors, similar to fire-eyes Sensor output is usually just a change of status (normally open to closed circuit, or normally closed to open circuit), or a low-voltage, low-amperage output to the processor (ex. 12V 4-20mA) Most of our processing units are PLC (Programmable Logic Controller), which takes the output signal from the sensor and triggers a response in a control unit and/or sends an alarm to a remote console.