Please i need a schematic for a circuit that has a display, that could be used to monitor cars in a park, such that when there are no cars, it will display E(empty), if filled it will display F(filled or full), then if not filled that means there are spaces it will display S(space). I need an idea of devices to be employed and if possible a schematic to guide me thro, thanks.
You need a car detector and a simple up / down counter. The car detector can be made of two sensor. I will describe them below. The sequence of pulses from 2 sesors can tell whether a car is entering or leaving (maybe you have 2 gates for entry and exit in which case it would be even easier) the parking lot. A simple microcontroller can intrpret the pulses, drive a software counter and the display to show E F or number.
For sensors, you can use an inductive loop burried underground. You can also use a load cell to sense weight. You can also use an infra red beam, an ultrasonic ranger, a photocell, a mechanical switch under the road. THere can be many possibilites
there is an article in a german ELV journal for park electronic, which helps you to park the car right in front of a wall. You can also use that for detecting cars in car slot.
You would need to ensure that access/exits for the car park have barriers that prevent in/out unless they are operated.
Otherwise the counting goes all wrong.
If so, the a counter on the times the barrier is raised at in, another at out can be used to determine capacity.
There are many ways of detecting the actual number of cars passing specific points, as long as they only pass them.
Even simple ones such as the rubber strip on the road to a relay/counter input work.
thanks guy for your suggestions, i think i'll need firstly a schematic for sensing a car at the park but the park is opened spaced. After that i'll move to the control unit. So whatever materials or links you may come across kindlyget me thro. thanks