This device is designed to count cars and people walking in and out of a farm gate entrance. It was designed for my parents farm, as there was a concern about strangers coming into the property at night. It does this by transmitting a pulsed infra-red beam across the entrance path. When it is broken (by a person or vehicle), the device will increment a counter and sound a horn. The count is displayed on it's LCD display.

The big box to the left is the main controller and receiver. The small box on the right is the quad LED transmitter. Each box is fitted to each side of an entrance. It is powered in series with a car horn which is located at the house via 100 metres of cable. Here is a top level schematic--

This system is heavily based on Terry Porters "Sheep detector" project, however, I have vastly improved the software design. The design uses fuzzy logic that measures signal and noise differences, and then adjusts beam strength/frequency based on that. The micro is continually measuring noise level and calculates a noise average. This noise average is compared with the pulses it receives. Therefore, it is able to intelligently discern what is and what is not a pulse over a noisy medium. It is less susceptible to false trigger or be saturated by a high emission source (like the sun or a cars head light).

The result of all this is that we have an adaptive device able to change beam strength/frequency based on it's ability to detect the beam. We want a high frequency beam... but, a strong reliable signal ; Therefore the micro will calculate the best beam strength based on the environmental conditions.

Unfortunately, the project became over budget. There were factors I didn't consider-- needing a good solid water proof chassis (my chassis was limited to the $$$$ I had at the time which was close to nothing), installing external power points to the house (to power the unit), and the cows eating the 100 metre fence cabling about a month after I laid it. In the end my parents decided that they didn't really want a horn going off every time somebody drove into the place, and so, the project was abandoned.

Note that Terry's "Sheep detector" circuits (which GATEC is based on) are private work. Therefore, GATEC will also remain private work.