Sensor Programming

[justin105]

Hi there,

i m currently trying to come out with a project as below

i m trying to use a USB webcam to detect any movement

i plan to implement this into a parking system to detect wether the parking is available

is Java programming suitable for a system like that?

becuz i m running on a very low budget(how much can a student spend possible on his project) mayb sum1 can suggest me with a better h/w ?

i have considered using LED to show status of the availability but i m not sure what to use to sensor it..

any help will be appreciated a lot

[MosaicFuneral]

Create a unique signal, emit it, watch for it, based on signal strength/
delay/whatever display whether there's a lack of space available.

Couple experiments to try:
http://home.earthlink.net/~lenyr/modlitbm.htm
http://home.earthlink.net/~lenyr/modlaser.htm

[justin105]

hi there,

thx for the fast reply

but i notice is all very electronic engineering is it?

i m currently a networking student..

as for my idea which is USB webcam to detect movement with php programming is it possible?

[wildgoose]

So you have no electronics background so you're looking for off the shelf components so as to build your project. You want to do sensor monitoring but keep focusing on a camera, which you really don't need. You in essence need to detect existence of a vehicle. The camera will be good for detecting motion. Have you investigated various security equipment available? Get an Ultrasonic detector and hook it up to a GPIO board, which is linked to your PC. The GPIO board can monitor multiple sensors, not just one. The only electronics required then would be wiring the harnesses. Though you could build an electronic circuit using a PIC but you can find the embedded board. Try www.digikey.com or www.mouser.com or a company like that!

[Colin Mac]

An IR LED and IR phototransistor will do for the car detection.
http://home.cogeco.ca/~rpaisley4/ATDetLong.GIF

You can look on http://www.ftdichip.com/ for creating a parallel or serial to USB interface.

[justin105]

An IR LED and IR phototransistor will do for the car detection.
http://home.cogeco.ca/~rpaisley4/ATDetLong.GIF

You can look on http://www.ftdichip.com/ for creating a parallel or serial to USB interface.

Hi Colin,

thx for ur idea

but i m a bit confused

creating a parallel or serisl USB interface for?

[Colin Mac]

To send the data from the sensors to a PC. Isn't that what you want to do?

[justin105]

So you have no electronics background so you're looking for off the shelf components so as to build your project. You want to do sensor monitoring but keep focusing on a camera, which you really don't need. You in essence need to detect existence of a vehicle. The camera will be good for detecting motion. Have you investigated various security equipment available? Get an Ultrasonic detector and hook it up to a GPIO board, which is linked to your PC. The GPIO board can monitor multiple sensors, not just one. The only electronics required then would be wiring the harnesses. Though you could build an electronic circuit using a PIC but you can find the embedded board. Try www.digikey.com or www.mouser.com or a company like that!

Hi there, the reason i wanted to use a USB webcam is becuz i have got some source in sourceforge.net, i'll b able to reference it but is a php programming

here's the link http://sourceforge.net/projects/phpmotiondetect/

[Colin Mac]

Since that detects any sort of motion then takes pictures, you would need to look at the pictures to be sure if there was a car in the bay.
In a project like this, you would also need sensors that indicate for sure whether there is a car. A program can then scan the lot and report the number of free spaces etc.

[justin105]

To send the data from the sensors to a PC. Isn't that what you want to do?

thx a lot for ur suggestion

i'll try to do see what i can do and keep u updated incase i need any help

[justin105]

Since that detects any sort of motion then takes pictures, you would need to look at the pictures to be sure if there was a car in the bay.
In a project like this, you would also need sensors that indicate for sure whether there is a car. A program can then scan the lot and report the number of free spaces etc.

hi Colin

regarding the diagram on http://home.cogeco.ca/~rpaisley4/ATDetLong.GIF

tat's an example for setting the IR to send data out?

can i know wat's the basic h/w i need for it?

[Colin Mac]

That's all that's needed for the sensor. The IR LED is on constantly. The output is taken from the collector of the phototransistor, which acts as a switch. When an object blocks the IR light, the phototransistor is off and the output is HIGH. When there is nothing in between, it's on and the output is LOW.

[wildgoose]

Indoor or outdoor parking lot? Sunlight washes out infrared!

Feel like digging up a parking lot, then halleffect sensors. A single loop will detect motion of magnetic metal. A double loop acts as a metal detector.

Pressure sensors.

Infrared - washed out by sun.

Ultrasonic - Can detect distance to ground, if short then being blocked then highly likely a car parked there.

Camera - Will need pattern matching to not shading difference to detect motion, etc. (Think MPEG MacroBlocks). Are pixel blocks being disrupted into a parking stall without going out? And what about those overline parkers?

First problem is the sensor. Work on it first!

Hint: There's a reason automated parking lots use choke points with vehicle counters.

[Colin Mac]

If it's just a proof of concept project, and you're not going to be near a car park. Then IR is fine.

[justin105]

ya is just a proof of concept idea

so here's what i will do

a IR transitor and one receiver tat's constantly on, once a object block it, the receiver will send out the signal right?

here's the problem.. how should i capture the signal and send it to the pc? as far as i know the FTDI link and USB thingy given by Colin seems bit complicated is it?

my idea is to add in an IC with calculating the counter programmed in it and send it to the PC

i planed to use rs232 to send the signal to the PC, but the problem is wat type of signal is it? how do i determine the type of signal?

as far as i understand the signal will be determine by the programmed in IC is it?

[Colin Mac]

The phototransistor is just a switch, the output is either the positive supply or ground. You could program a microcontroller to read the outputs and send serial data to the PC's serial port.

The FTDI devices are just a simple way of creating a USB interface.

[justin105]

ya tat's what i m planning to do.. i haven figure out what should i do when the signal is transfer to the PC.. mayb VB or C++ to program a calculation and display

i m trying to get the h/w and try to get the signal to the pc now, tat's the stage i m now

[wildgoose]

RS-422 or RS-485 would be an appropriate serial connection. Handles distance. Since it sounds like you're putting a processor (may I recommend a PIC) directly attached to the sensor(s) you may consider putting an LED on an output driver as well. You can self test by toggling the LED on and off and monitoring the input sensor.

[MosaicFuneral]

i m trying to get the h/w and try to get the signal to the pc now, tat's the stage i m now

So you've experimented on a breadboard and observed a working design; first, before taking the leap of hooking it up to the PC?

[JameB]

Have you thought of using a photo cell(or a solar cell) and a laser(visible or invisible)? It can also be used to detect movements. If it suits your needs, then programming and other things can be so much easier!

Just a thought.

[justin105]

been bz do din update much abt my system

currently i have manage to come up wif the circuit to send data to pc thru serial port

but i have no idea how to start process the signal sent thru the serial port

i browsed sum website and i have no idea what is it abt

i wanted to come out wif a system that can read from a serial port

any ideas where i can start searching info from?

thx

[JameB]

Perhaps this thread will be helpful :

http://www.daniweb.com/forums/thread56329.html

Also, C++ is NOT the only language that allows serial port communications. MAY BE there is a language that allows and makes this process much easier.

Good Luck!!