I am an avid airgun user and I am bored of shooting the average paper printed targets. So I was thinging of making some games. E.g. speed shoot metal targets that knock down and I could time them with a PIC etc.
But I would like to create the paperless target. So I had an idea of creating a bank or lasers from laser pens to some LDRs and then sense when one is broke by a pellet and then recording which one was broke etc. One set for vertical and one for horizontal. the problem is that a pellet is so small I am not sure I could have so many LDRs together to make sure I collect the 3mm pallet as it passes.
Anyway I am stuck and would like to see if you guys had any ideas?
Thanks for your time
Danny
That's gonna be a heckuva problem. It's a matter of sensor resolution. The only things I can think of that would work is a linear CCD that can be salvaged from a digital copy machine, but it won't be easy to use. It's not a trivial project, and you will do ALOT of reasearch before you have a working project.
Thanks for the reply. Yes I thought so too. Its not easy but I got married the other week and now I need a hobbie otherwise I will have to talk to the wife
Then how about a bank of small LDRs, one light shining on them in a box, the PIC takes a calibration reading. Then fire the pellet and see which of the LDRs resistance changes. It may not be accurate but I wonder how good it will be?
Thanks for the reply. Yes I thought so too. Its not easy but I got married the other week and now I need a hobbie otherwise I will have to talk to the wife
Then how about a bank of small LDRs, one light shining on them in a box, the PIC takes a calibration reading. Then fire the pellet and see which of the LDRs resistance changes. It may not be accurate but I wonder how good it will be?
resolution is a big problem... while you could use a simple camera, the volume of data far exceeds the capacity of ANY PIC.
an "inexpensive" HD sensor ($30), can capture full res (2592H x 1944V) at 14 frames/second for a 98MHz PIXEL rate.
what you are proposing would require an FPGA to read the target coordinates and relate just the coordinates to the PIC. at least you can probably arrange for it to be simple math as opposed the the project I am working on: **broken link removed**
Atually, there has been nothing of the sort proposed. I said a linear CCD, not a full 2-D array. After more thought, I realize the event just happens too fast to be capured. I see no solution for optical target sensing.
Atually, there has been nothing of the sort proposed. I said a linear CCD, not a full 2-D array. After more thought, I realize the event just happens too fast to be capured. I see no solution for optical target sensing.
that is impact based and my old RWS rifle would go right through it. at 950ft/s on a .22 i put 2" dia dings in 20ga garbage cans with target pellets and punch holes in them with steel pellets.
piezo sensors along the edges would do it. latch on to the first one to respond gives the strike location on a given edge. if you are really clever and have a lossy target material the first to respond would be the location and the peak output could register a distance.
I was thinking about a contact membrane. But it would need to be both flexible and tough. Don't know what material would work though. Perhaps some of the new "memory" materials????
How about the piezo idea with 4 or 5 metal rings around a bulls eye put together with say silicone (as a damper) holding them together. Each ring with its own piezo.
How about the piezo idea with 4 or 5 metal rings around a bulls eye put together with say silicone (as a damper) holding them together. Each ring with its own piezo.
silicone gap would have to be less than half the diameter of the pellet and would still take a beating. at that point you could however simply use a small piezo pickup and sense the impulse created from the hit.
The readout may not have to be that fast. There is a way to read out the CCD at a more normal rate (say 50-100 times/s or even slower depending upon the sensitivity you need).
A CCD detector well will store the image it has captured for some significant period of time until it is read out. Suppose you illuminate the bullet area from the same side as the CCD with a string of narrow angle LEDs so that it can detect the reflected light from a bullet passing through. So you would periodically read out the CCD to see if and where is has detected the reflection from the bullet (you don't really care exactly when). The peak detected signal would be the location of the bullet on the linear CCD.
The difficulty would be protecting the CCD from significant stray ambient light so it wouldn't saturate the CCD well while it is waiting to see the bullet.
It could be possible to detect the sound of a passing pellet. If you use three microphones (or just a simple stereo microphone) and some signal processing, you could be able to trilaterate (Trilateration - Wikipedia, the free encyclopedia) the point where the pellet passed the microphones.