Garage door – Part 2

Just to be clear. I don’t have ADD, I just like to keep moving forward…..

While waiting for inspiration on the dog door dilemma (One of the guys at work has a great idea and I am tinkering around with testing it) I turned my short attention span to the detecting the Smart Car in the garage problem.

Just as with the dog door, we thought about microswitches in this case as well, but having them attached to something seemed a bit old fashion.
The fact that the Smart is red did not escape my attention either, you can buy color detecting sensors these days pretty cheap. So I could detect the red door and know the car is there.
Video camera object detection was also considered (and was/is more than a passing thought for the dog doors as well).
Lasers are always fun (Got a blog in mind for that topic as well), so thought about that option.
Ultrasonic range detection. Terry was in the robotics club at high school and they used one on their bot, so we are looking for an excuse reason to use one of them around the house….

In the end, we settled for a loop of wire on the ground. Just like they have for traffic lights. Have always wanted to play with that sort of thing, so it was a good excuse for me to tick it off my list.

There are lots of circuit diagrams for making one out of bits on the web, and I thought about going that way, I really miss playing with electronics, but in the end, a lack of time won over.
So, we brought a unit off eBay.

First up, they don’t come with a coil, so I went to the local electronic shop (can you believe that there is one, just one in Temecula, and its within walking distance of Opto?) and got a spool of wire.

The wire has to be made into a loop that will sit on the floor under the Smart Car, so I wound it around the rubbish (trash) bin (can). As you do.


It was pretty much the perfect size, and being a cone, meant that the coil just slipped off. (Freddy freaked out when she saw me wrapping wire around the thing. Really? We have been married for some 24.3 years and she still worries when I start wrapping stuff with wire??)

Added some tape to keep it together. (Look at me go BA and keep it all neat).


The unit itself is very straight forward, you add power, connect the coil and it has a switch (relay) output. 50 bucks. Hate to say it, but why muck about with soldering and chips and stuff when you can just buy the box and get on with life?


Here it is on the floor, ready and waiting……


Relax Sue, I am going to throw a nice rug over it and hide it, but wanted the geeks to see it first…..
There is some coax cable going from the coil to the box, you need to shield the signal so it does not pick up any stray interference.
I wish there was a join the floor to put the cable in, but there aint, so I will probably get a little rubber to put either side of it so the cable does not get squashed under the terrific weight of the Smart Cars front wheel.

I hooked the switch into the Opto controller and we are done.
The system now knows when the car is in the garage and so it knows when its time to shut the garage door.

Now, I need to interface the Opto controller with the garage door itself… Wonder what I will get distracted with while I get that set… oooo shiny….