Crossbeam

 

Crossbeam Sensor.
As you can see form the images below, the frame is made from plastic water pipe, I tried electrical conduit but found it to be too flexible. Using pipe for frames is of course  not new, so I will not take any credit for the idea, also the crossbeam was also made by someone else as well, but where mine differs is I have used lasers instead of infra red, because the lasers will work over larger distances, and are easier to align. also the original idea had the wire affixed to the exterior of the frame, held in place with tape. Though my idea takes a little longer to construct, I believe it to be much neater and more efficient.
Size of the frame doesn't matter to much, it can be as small as two inches or large enough to catch larger animals walking through it. Though a larger size I would think, would need a bigger diameter pipe.
Start by cutting four equal lengths of pipe, mark the centre's and drill holes in two of them to suit the laser modules you are using, in the other two drill hole to suit which ever detector you plan on using, I chose Photo resisters (LDR"s) simply because I had them on hand, but phototransistor's will work as well, maybe better. Directly behind these holes I made a cut out  with a dremel type tool so as to be able to get at the circuitry, not that there is much involved in mine, it depends on the voltage requirements  of the laser modules to be used.
Wire up the circuitry and thread it though the pipe and corners, measure the distance from the centre to the bends making sure they are all equal, once it is all in place line up the lasers and detectors, by twisting the pipes, and tweaking the components, adding power to the laser's will be a great help, once aligned put a little super glue against them, and some hot glue to hold the pipes in place. Attach inline 3.5 sockets to the leads and where done.
I wonder if we could parallel more lasers and LDR's, I might give it a try.
I had tried a crossbeam before, using a none microcontroller unit, and found that to trigger it you had to break both beams at the same moment, but with this one it doesn't matter which beam you break it will fire, I thought at first that this was because the Camera Axe was  turning off the lasers, but on testing this with my Arduino Prototyping setup, i t performed in the same way, and it is not set to turn off the laser's.
I took a couple of pics with it, I just threw the model through the beam, I know it is not very well focused, but it proved it worked. I set a 70ms delay. this would depend on how fast the subject was moving, I haven't tried it, but should imagine that dropping a heavier object through the beam  would increase the speed, thus the delay. My object at 70ms only travelled about 4-5 inches.
On reflection, as this stands it would be very hit and miss for insects, there is too much space around the beams, But if you were to make one on a much smaller scale say 2 inches square, and set it close to a flower then maybe it would be ok.
I think my next project would be much better.
 
 
 

 

 

I haven't as yet tried it in real life situation, it would  more than likely take much
more trial and error in setting up, to allow for shutter lag etc..
Link to Lasers below.
https://sslrelay.com/odicforce.com/shop/article_OFL85/New-Micro-Red-Laser-Module---5-Pack.html?sessid=C9hMotrTiiwudszXISr2qYXzizv2Cb4Tv5wjeRvhzYQqUKIGLGOmpt4NK4fyjM8I&shop_param=cid%3D13%26aid%3DOFL85%26
Hope someone will find this useful.   Ernie