Need an idea for car presence

[abicash]

Ok i found this solution from Honeywell

what say guys?

 

[colin55]

They cost between $20.00 to 27.00 each - an absurd price. Even a microcontroller costs only $2.00

 

[abicash]

i agree ..but honeywell does the same thing with any of its devices

 

[colin55]

For your situation, a simple 2mH - 10mH inductor in the ground, and fed with 20kHz is all you need to detect a car. The spacing of the inductors will detect length and this will determine size. If you have 3 inductors in alignment, you can also determine length as you know the speed of the vehicle.

 

[Boncuk]

I'm not sure if you need to measure each parking place or only at the entrance. If it is a drive thru it seems like 2 ir sensors like what are used in tv remotes and tv's would work. Spacing is such that if both are blocked it is a big car. If only one at a time is a small car.

Do you know about habits when parking a car?

I've seen many parked cars the same way a cow releases her digestional leftovers.

 

[Boncuk]

For your situation, a simple 2mH - 10mH inductor in the ground, and fed with 20kHz is all you need to detect a car. The spacing of the inductors will detect length and this will determine size. If you have 3 inductors in alignment, you can also determine length as you know the speed of the vehicle.

Please note:

Seems these schemes will require infrastructural changes,which may not be feasible in my current scenario.

 

[ronv]

park o meter

The ir is simple. Just an ir source at 40KHZ and the off the shelf TV detector. Detect the absence of pulses. The whole thing is less than $10. But, your problem is more complex. You don't know how far into the space the car is. Is it correct to assume that length is the factor you want to check? If so what is the tolerance?

 

[Boncuk]

Hi abicash,

here is a cheap and reliable solution for your problem.

You require three IR-barriers for each parking lot.

A small car will only interrupt two beams, regardless of how the car is parked.

A large car will always interrupt three beams.

(If you can't afford a Mercedes 600 just park a rusty old truck there. )

Regards

Boncuk

 

[abicash]

The ir is simple. Just an ir source at 40KHZ and the off the shelf TV detector. Detect the absence of pulses. The whole thing is less than $10. But, your problem is more complex. You don't know how far into the space the car is. Is it correct to assume that length is the factor you want to check? If so what is the tolerance?

Yes the car can be considered available in a fixed parking spot of maybe 10ftx10ft so any ir detector should work IMO

here is a cheap and reliable solution for your problem.

Good enough Although throwing in another beam wont hurt.

 

[Boncuk]

Yes the car can be considered available in a fixed parking spot of maybe 10ftx10ft so any ir detector should work IMO



Good enough Although throwing in another beam wont hurt.

... but waste.

 

[abicash]

Hi Boncuk

I was doubting the 3 beam theory since a small car may only hit 1 beam and what if a big car just neatly lined up with 2 beams instead of 3.
This i think has to be found out empirically.
What do you think?

 

[Boncuk]

Hi abicash,

you won't have to find out the distance between barriers by experiment.

The size (length) of the parking lot must be known to place the barriers at distances taking care of any car size (being allowed to park there, since an 18-wheeler will certainly not fit.)

Even if it's a matchbox car only hitting one beam it must be something being parked on the lot (which calls for payment)

From my graph there is only one way for a big size car to break two barriers - if it is parked (partly) outside the parking lot.

I guess a three barrier solution covers all cases.

Regards

Boncuk