A true novice needs help, electronic game trail alert

[jab]

Hi,
    I need electronic help!!!  I am a retired Industrial Arts teacher so I know about soldering, basic electric wiring, and mechanical stuff but my formal education came too late to learn any electronics. Electronics and gadgets fascinate me and I am eager to learn.  A friend of mine keeps showing me how cheap components are, he has a computer background but nothing in electrons so I decided to see if I can get help and get started.  This maybe the wrong place and if so please guide me to a site that might be willing to help.
   The project I would like to build is a portable game trail alert system.  I am hunter but even more I love to photograph wildlife.  The problem is they usually come up on me before I can get my video camcorder ready so I have resorted to using driveway alert systems from Harbor Freight.  I put the sensor out some distance on the trail and then use the receiver to tell me when something breaks the beam.  I took apart the receiver and in place of the beeper I soldered one of their cheap led flashlight heads in its place.  Instead of getting the beep I get a flashing light.  The units are different channels which works good so I know what direction to watch.  Unfortunately that means I have to have a completely different receiver for each of the four directions.  The transmitters are not really  small, about  2”x3”x4” and uses a 9v battery.  The receiver is the really big and heavy one about, 1.5”x4”x5” and uses 3 batteries c size!  I would have to use four of these, which translates to big and heavy.
   What I would like to build is four separate transmitters as small as possible with decent range, about 100’-150’ or more, on different channels and one receiver with four different lights, one for each channel. 
   I don’t have enough knowledge to know if this is possible.  I think this would be a great project and I am willing to learn!
   Thanks ahead of time, jab.

[jeroen79]

How about using a 4 channel 433 MHz transmitter/receiver combo?
(http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=330734446785&category=168248&pm=1&ds=0&t=1447663833974)

The transmitter has 4 buttons and the receiver has 4 corresponding outputs.
Get 4 sets and make the sensors 'press' a different button.
Keep one of the receivers and add lights to it's outputs.

[jab]

That sounds like a great Idea!  Now how would I get a ir sensor to "press" the button and what kind of sensor would I be able to use?  Thanks for the reply.

[jeroen79]

That would depend on the sensor.
Some will have an internal relay or transistors that will open or close when the sensor detects something.
If you remove the switches from the transmitter then you can wire the relay/transistor in place of them.
Others may output an analog signal that must be processed.

If you know the brand/type of the sensor you can lookup a datasheet for it.

If you already have these driveway sensors/transmitters and they work satisfactory then you could use them.
Just disassemble them and use the sensor.
Otherwise you can use passive infrared (PIR) or a beam sensor.