How to use a photocell or a sensor to turn on and off switch

[atif7865]

Hi,

I am very new to this whole electronics thing but I think I can do my project with a little bit of guidance since its not a big one.

I need to have the motor for an arm gate to operate only if there is a car in front of it. for this project I thought I would use a light-sensor or a photocell and a source of light beaming straight into the sensor across the path of the driveway. if a car stops in front of the arm gate the beaming light would not reach the sensor anymore and that is when I want the switch for the arm gate motor to turn on.

I think I am on the right path, I just dont know what specific parts to use and how to design the circuit (I THINK THAT IS THE WHOLE PROJECT RIGHT THERE

I would appreciate any help to get this project ahead.

thank you so much guys..

if you need any other info please let me know, like the size of the motor, voltage, amps etc.

thanks again guys

 

[RCinFLA]

Probably going at it the wrong way. If you want any car to open the gate then put in a metal detection loop within the driveway. This is same as used for public traffic lights. These are available. My neighborhood uses one for gate opening to community.

Light sensor is going to give you a number of issues. Sunlight, reflections, etc.

If you only want selective vehicles to open gate then get an RF controller, similar to garage door opener.

 

[kinarfi]

I agree about the issues with light, but if you go that route, put the sensor at the end of a tube, the longer the better, that is painted black on the inside to absorb ambient light and use a focused light source, aiming will be importan so things need to be solid.

 

[kinarfi]

Here's a couple of schematics I have found, I plan to use one of them to turn on some lights that will be turned off by a timer.

 

[atif7865]

Thank you so much all you guys. I understand the problem with the light and I had in mind the idea of focused light. Thanks to kinarfi about the idea of putting the sensor in a long tube painted with black color.
I think the first schematic that you posted is what i probably need. I will go ahead and create something like that and let you guys know how it went. I still appreciate if there is any better idea on this topic.

Thanks a lot

 

[ronv]

I always like the ir transmitters and receivers used in tv remotes as they have good range and better immunity from ambient light because of the pulsed frequency and built in agc. The circuit is a little more difficult but......

Look at TSOP36136 or similar.