Building a heater vent rover to investigate source of strange smell

This $4 webcam got snagged in the vent. After managing to yank the tape measure out, I still wanted to retrieve this flashlight.

Few days ago, I started smelling a strange odor emanating from heater vents. It got worse and worse without any promising suggestions from friends or family. Many years ago my parents encountered a similar situation but after paying $100 for a handy man to find nothing in the vents, nothing was done, and the smell slowly faded and was forgotten. I didn't want to call over someone without being able to give them useful information so I set out building a contraption to see down the smelliest vent.

As all good movies, things went bad very quickly:

And so begins the rescue operation and the birth of the Cuddleburrito Vent Rover. 

The Problem (Opportunity)

 

The Solution

Time was of the essence. Who knew how long the batteries in the flashlight would last. There was already one casualty, the webcam whose USB cable was forcibly yanked out while recovering the tape measure, but no more! This was my fault and ignorance wouldn't make things right. I really wanted my favorite flashlight back! I swore that no LEDs would be lost in vain today.

The barebones frame uses a thick cardboard roll as a big front wheel. 3D printed hubs were paired with scrap acrylic for smooth rolling. The rest was hot glued with craft sticks and zip-tied together.

The final contraption included a portable USB battery to power a servo + microcontroller. The "safety tether" was a 4 wire braided cable I used to connect the arcade buttons and control the arm from outside the vent.

Dry run to test grabber mechanism. I planned to use FaceTime between laptop and iPhone in the vent to see what was going on. Seemed to work ok on dry land.

The Rescue

There's a 31 minute video from the first attempt. It's a hair pulling endeavor where the grabber would graze the flashlight's lanyard and drop it. However, we had come too far to stop here!

Mechanical upgrades and a firmware flash in the field gave the rover added functionality to complete the task. First was bending and forming the plastic grabber into more of a hook shape. This allowed for an easier time threading loops with the grabber. Secondly, the grabber control firmware were modified so that button presses incrementally rotated the grabber instead of rotating the entire 90 degrees each time. Observation and small iterative changes.

Cue Mission Impossible music:

Flashlight grabbing begins at 1 minute mark

 Shortly after emerging from the vent, the victim is dim but in stable condition

Shortly after emerging from the vent, the victim is dim but in stable condition

Sequel?

Although the rescue was a great leap forward for America, my Mom remained focused on the mission: "In the meantime, did you learn something on the creature or source of the smell?"

"No, Mom, but I got a cool new rover now and had a really great Sunday."