Tom is an engineer who has applied Soft-I/O to a number of industrial processes, so when he bought a new second home in the Sierra Nevada Mountains in California, he saw a new application for Soft-I/O. Tom's problem was that his heat is provided from propane that comes from a tank on his property. Tom lives three hours from his mountain home, so he needed a way to determine if the propane was going to run out and leave the home cold and frozen. Then too, he rents out the home as a ski cabin, so he needs to know how much propane is in the tank after each guest. He does not want to run out!

So Tom replaced the manual gauge on the propane tank with a transmitter that produces a voltage proportional to level. He then simply hooked up Soft-I/O and configured three pins to supply power and measure a voltage. Done. He then hooked it up to his Internet service and now could remotely monitor his tank level. (At the same time, he hooked up a few temperature sensors to monitor indoor and outdoor temperature, but that's not what we are here to talk about today.)

Now we can tell the story! Tom was on a business trip and had just landed in Chicago and was waiting for his next flight. He pulled out his smart phone and went to his Soft-I/O module on the Internet. He could instantly tell that the propane delivery person had been there since the previously near-empty propane tank was three quarters full. Why, he wondered, didn't the driver top off the tank?

Tom flew on to Cleveland. When he landed, he again pulled out his smart phone. To his surprise, the tank was now barely half full! Where was the propane going? Tom frantically called his neighbor in the Sierras. After a few minutes, his neighbor reported--in somewhat of a panic--that there was a strong smell of propane, and a loud hissing noise coming out of the tank. There was a big leak!

Tom got right on the phone to the propane company. "Let me check," said the clerk, "I don't know if the delivery person has been there yet."

"Oh, yes," said Tom. "He's been there and left the tank leaking!" Sure enough, the clerk reported that the propane driver had been to Tom's house and was now heading back. The driver sheepishly reported that he had not secured the tank connection, and the leak had ensued.

Tom felt lucky. It's not uncommon for propane tanks in the snow country to leak. Because propane is heavier than air, it can follow snow tunnels around the pipe and fill basements wiith propane. Only a small spark is needed to lose the whole building.

Tom wrote us to say, "Thank you!" We had nothing to do with this case study, but we are thrilled to hear that Soft-I/O saved the day and perhaps even a home.

A light tower is a deceptively simple device.  It has maybe four lights in a stack that sit above a tool on the production floor.  In semiconductor fabs where wafers are processed into chips, light towers can help operators and technicians identify tools that need attention.  So what's so difficult about this problem?