Assignment 4: Burning Down the House

I have to admit, I kinda thought this particular solution was a little cliche at first, but then just this week, I accidentally left a burner on low, and walked away for an hour. Luckily nothing got too badly damaged, but I’ve gained a new respect for practical solutions to everyday problems.

Here’s the plan:

Attach a sensor to the knob to know when it’s not in the off position. This could even be a simple switch (today we’re using a potentiometer in case we someday want to know how high the burner is set).

From there we add a sensor to tell when the cook has walked away. We don’t really want a visual indicator that’s always on when the burner is on, or we’ll learn to ignore it. Today I’m using the HC-SR04 provided in class.

From there it’s just a matter of selecting a timeframe, and an indicator. For the purposes of the demo, we’ll use 5 seconds, but in real life something like 5 minutes is probably about right. For an indicator, I’ve gone with a red LED for the demo, but perhaps a text message or IFTTT notification on my watch would be more practical long term.

Below I’ve laid out the state diagram, wiring of the demo, and a picture of it in action. There’s a link to the zipped code at the bottom.

Let me know what you think!

Author: Matt Franklin

I'm a recovering engineer + sales guy... BSEE from UMD 2004, and then 15 years of working with signal processing, AV, control systems, networking, and other gadgetry (mostly B2B). Now I'm in the Master of Human-Computer Interaction program, graduating in August 2020. I have pretty solid experience with: - Linux - audio - video - rs232/422/485/midi/dmx protocols - sketchup and other cad tools - soldering - music (mostly guitar, but others too) - general troubleshooting - networking (wired + wireless) - signal processing - streaming video/audio - python I have some experience with or am mediocre at: - woodworking - welding - laser cutting - sewing - reverse engineering - ML (none really but I'm currently in a class) - some javascript - rusty with C++ and Java, but used to be decent - tube amplifiers - RF

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