Smart parking system

A 6-slot car park with an entry barrier, an exit barrier, and a display that always shows the real number of free spaces. It's the kind of system a municipality, hospital or shopping centre in Kathmandu could use, and it scales up by adding sensors.

Why sensors in every slot

A lot of parking counters just count cars in and out. That drifts during the day: a motorbike squeezes past, someone reverses out the entrance, a sensor misses one. Here every slot has its own IR sensor, so the free count is the actual state of the car park, every second.

What it does

• The LCD shows Free 3/6 and a slot map like 1X2-3X4-5-6X (X = taken). A FULL lamp lights when there's no space.
• The entry barrier opens only if a slot is free. When the car park is full, the driver gets a beep and "PARKING FULL", and the barrier stays down.
• The exit barrier always opens for a car leaving.
• A barrier never closes on a car. It waits until the car has fully passed, plus 2 s. If a car appears under a barrier that's coming down, it goes back up, even when the car park is full. Safety comes before the slot count.
• If a car sits at an open barrier for 20 s, the buzzer calls the attendant.
• Slot sensors are filtered for 1.5 s, so people walking past and reflections don't flicker the count.
• Barriers move slowly and smoothly (about 1 s for 90°) instead of slamming.
• Every event is logged over USB as CSV: EVENT,seconds,event,free_slots.

Files

Building it in Proteus

1. Add ARDUINO UNO, LM016L, 2 × MOTOR-SERVO, BUZZER, LED-RED, and 8 × SW-SPST or LOGICSTATE for the 6 slots plus the entry and exit sensors.
2. Wire it as in images/wiring.png. Each sensor input reads LOW when a car is there.
3. Set the Arduino's Program File to firmware/build/smart_parking.hex and run it. Close the entry switch to bring a car in, then close a slot switch to park it.

Save it as proteus/smart-parking.pdsprj and commit it.

Scaling up

For more than 6 slots, use 74HC165 shift registers (8 slots each, 3 pins total) or one ESP32 per row reporting over Wi-Fi to a display at the gate. The barrier logic stays the same.

Testing

The test covers both barriers down at start, the first car with the 2 s close delay, the slot sensor filter, filling all 6 slots, the FULL lamp and a refused car, a car leaving, the tailgater safety re-open when the car park has just become full, and the attendant warning.