I want to build a car parked detector for my garage

Question

Hi,

Does anyone know how those car detectors work in shopping center carparks? You know the ones that show a green or red light depending on whether a car is parked in the space. I want to make one that will tell my phone if a car is parked in the garage or not. I was thinking of using an arduino connected to a"Ultrasonic Module HC-SR04 Distance Measuring Transducer Sensor for Arduino measurer" to measure the distance from the ceiling to the floor/top of the car, but someone said they thought they worked by using a magnetic field.

Gez

mcb1 · Accepted Answer

Gerry The ultrasonic would work. You can set the maximum distance to something less than the floor. It will return nothing if it doesn't detect an object within the range. If there is an object that reflects, then it will return a distance. You can use IR beam to send and return from a reflector fitted to the floor. Most use a modulated (38Khz) so that ambient light doesn't affect the ability to detect. mark

e14 Contributor · Answer

Hi I think its easier to make detector with a laser pointer and fotoresistor because you don't need to know the exact distance, and its cheaper, the coding is a lot easier. Tom

colecago · Answer

Alternatively, if you want something sent to your phone, IP Webcam. I have a few at my house and I can view my garage (and make sure the door is shut) and see what my dogs are doing. They were about $60 a piece.