I have a problem where there is a pond next to my driveway. I come home at night and many times there are frogs on my driveway. Many times they are difficult to spot as some are tiny and there is also debris. My thought is it have a detector made of two lasers or ir led's flashing at a fast pace and at different rates. If they are placed next to each other and made to shine down the length of my driveway about 10 to 20 feet they will detect which direction the frog goes. In the program it can take this information and keep track of if there is a frog still on the driveway. The program can also be able to diagnose a problem by monitoring how long the sensor has been blocked so if something falls in the way of the beams it can alert of a problem. i wanted to post this as i am not sure if this is the best way to go about this or how to program it.
Do you want to get rid of the frogs, or do you want to keep them alive ?
I don't know how a laser or IR leds can be helpful. The frogs are cold-blooded, so a IR motion detector will also not work.
Is there a bio solution for this, with frog repellent or something like that ?
You could make air bubbles in the pond with a simple air pump. That reduces the flies and the frogs.
Or make a barrier with a small fence or salt. Just like dogs, frogs hate to walk over salt.
I assume from your post that you are not looking to get rid of the frogs, just trying to avoid killing them inadvertently.
My guess is that there is not an obvious way of easily detecting them on a driveway like that & if you could how would you know the difference between frogs & other stuff.
I would suggest that using a non-Arduino type approached may be better.
I did a quick search on google and found the following:
..some of it almost funny other parts alarming. Fortunately, we don't have issues like that where I live.
Best of luck on your quest & do post back if you find anything close to a solution.
You can map the drive way with ping sensors (depending of coarse on how long it was) ping it from above with a pan tilt setup then map the data kinda doubt the arduino can handle all of it. So it may have to be collected with arduinos and passed to a computer or something like a beagle board or raspberry Pi to do the thinking.
How about a leaf blower, and anything left is a frog.
wow these are great thoughts. My thought was to have two beams parallel to the driveway between the pond and the driveway. Two two beams depending on which one was crossed first and then what one was crossed second would tell if a frog went from the pond to the driveway and if they came back. If the count of frogs that went from the pond to the driveway increased then there would be frogs on the driveway. If the count of frogs went back to 0 as in all frogs that migrated to the driveway went back to the pond it would be safe. If the frog count was still positive and no frogs were on the driveway as in they didn't return the same way they left or went onto the lawn the other side of the pond it would still be a cautionary scenario. If the beams were blocked for an extensive amount of time then i could be alerted of a possible problem with the system. I feel it would be easy to add a wifi adapter so i can have a web interface and also a few led's set up for my family that do not want or have the knowledge of the web interface to also know if there weren't any frogs on the driveway or to use caution.
I don't think a laser sensor or code for it would know difference between a leaping frog or a wind driven leaf/debris.
Even if it were a false positive it would still be a caution. I know that it would be harder to actually track the definitive fact of frogs being on the driveway. My thought is only a device to warn the possibility of frogs and to use caution when traveling on the driveway.
Have you thought of releasing frog eating snakes in your driveway ? XD
Then why not just be always careful about it. Seems easier and more efficient.
Or just put some kind of detector on both sides of the driveway and if the line has been broken means something is/has been on the driveway. Doesn't seem better than the first option to me, but if that if what you want, it may work for you.
Seriously though a light curtain should work. What are the dimensions of the driveway ?
20 to 30 feet.
In Australia, cane toads are encroaching steadily southward from Queensland down through New South Wales. 
When driving, it is considered substantially more satisfying to hit them squarely with your tyres, mouth-end first in order to maximise the "pop".
Your idea is feasible. Whether it would actually be useful information or not you could only guess, or build it and see. It seems to be a pretty good starter project.
I think you might be adding complexity with the flashing thing. Usually when they do these things for people counters in stores and such, they just have two beams and two detectors, don't they?
These light beam based detectors work really well for short distances. If you're going longer distances, the light scatter from frogs closer to the light source and farther away from the detector will fuzzy up the shadow some. You might have to use laser beams or focus the light somehow. Which isn't a big problem except it might make your light sources more expensive. You also might have to make a black tunnel around the detector so you don't get ambient light messing up the signals. Less of an issue if you're only going to need to detect the frogs at night, but you might miss any that hop over there before sundown, and stay there. Or you might get interference from your headlights when you drive up, which could be a problem if lots of frogs start to hop away when you drive up.
Hook up a garage door opener to run a sweeper across the driveway to sweep the frogs out of the way.
Turn on a high pressure water hose sweep it back and forth over the road surface for a period of time.
Put up a 1 foot high mesh fence on either side of the road . May be electric.
Peter_n:
Do you want to get rid of the frogs,......
you thinking that one might want to up that lazer to a good 200 watts ?
it would seem that instead or range finding for movement, it would be more on the targeting side.
on a more serous note......
a simple targeting device and a water cannon. just a pops of a pint of water should move one off the driveway.
the ultimate solution is to elevate the driveway so the toads can freely move under.
or use a de-frogger, and automate it. might have to scale it up for larger frogs.
All you need is a 3" hollow elevated ramp .(with snakes inside XD)
is there an Arduino Trebuchet ?