Summary

Ok. Here is something no one else will ever make, but for edification I must publish it. To make the story short, my daughter’s bedroom did not have proper cooling/heat supply through the ducts. There is no crawlspace under the house, but all the supply ducts located under the floor. AC contractors told me they’ll have to tear up all the floors in her room plus 2 more rooms to figure out the problem. I’ve designed this crawler to get it into the 7” supply pipe, and provide a live feed via a HD Microsoft webcam, so I can inspect the ducts and figure out where the bottleneck is.
The tracks and motor/gearbox are from a Tamiya 70100 track and wheel set. The camera is a Microsoft HD webcam. The lights are from a $1 harbor freight over the counter pocket light
http://www.harborfreight.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/i/m/image_14142.jpg.
I used only the reflectors and PCB, and replaced two LED’s with high intensity ones. The crawler can move forward and backward which is pretty much enough considering it’s inside of a duct. There is a cable attached to it, which provides the lights and motor with power. As an addition the webcam has a 3ft USB cable, and I added a 12ft USB extension, so I can send the beast into the duct for 15 ft. I tried to add another 12ft extension but the webcam did not work anymore. So 15 ft is pretty much the limitation of the current USB technology.
Found an old remote control for some kind of a toy, which had a battery pack, and I used it for the project.
For reference I include the tamiya track and wheel set stl file, should someone like to use it to design something new. The whole assembly stl file is included too.