Circuit to detect a pipe wall
Circuit to detect a pipe wall
(OP)
We need suggestions on how to detect the outlet of a 1-inch pipe. A unit will travel in the pipe and detect the wall and we need to detect the pipe end in less than 4 millisecond. The sensor must be electronic and we are thinking of an IR-sensor. The sensor must be insensitive to daylight. Do anybody have a proposal.





RE: Circuit to detect a pipe wall
Any other info you may be able to tell?
<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032
RE: Circuit to detect a pipe wall
RE: Circuit to detect a pipe wall
<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032
RE: Circuit to detect a pipe wall
The trouble with IR is that the surface will affect the reflectivity. Is it old or new pipe? Old dirty pipe may absorb most of the light and make the item think it is in open air. Unless you can guarantee the nature of the surfaces, you would have to do extensive testing to ensure the IR would work. Make sure you modulate the IR at some rate (say 50kHz on/off rate) as this will make amplification and detection easier.
If the surfaces are clean then IR is a good bet. If the surfaces are a bit arbitrary then I would consider ultra sound up at 40kHz.
Micro-switches should not be ruled out. The easiest answer is a magnet on a plunger mechanism. If the magnet is allowed to move away from the case then a reed relay inside can be de-activated. This is by far the easiest sealed system as the magnetic field passes through the sealed interface into your object. You "just" need a spring loaded magnet holder assembly which lets the magnet move away when the pipe wall disappears.
RE: Circuit to detect a pipe wall
I'm really curious as to the application... igniting pellet? Sounds like a potential weapon.
RE: Circuit to detect a pipe wall
The sensor could be activated only after an accelerometer see X g's for Y amount of time.
RE: Circuit to detect a pipe wall
RE: Circuit to detect a pipe wall
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If we learn from our mistakes,
I'm getting a great education!
RE: Circuit to detect a pipe wall
RE: Circuit to detect a pipe wall
----------------------------------
If we learn from our mistakes,
I'm getting a great education!
RE: Circuit to detect a pipe wall
"Venditori de oleum-vipera non vigere excordis populi"
RE: Circuit to detect a pipe wall
When you place it in the tube you could sense the oscillation by external equipment to verify you're in a safe mode.
I agree two modes of safety should be used, or three. A simple timer to not allow the event until it has travelled X seconds from turn on would be good too.
kch
RE: Circuit to detect a pipe wall
<nbucska@pcperipherals DOT com> subj: eng-tips
read FAQ240-1032
RE: Circuit to detect a pipe wall
RE: Circuit to detect a pipe wall
If you mounted a coil around the the end of the pipe outlet you could create a magnetic field that the object passes thru.
Inside the projectile you could use a set of contacts either opened or closed by the field as it passes through it. This would allow you to carry only enough power required to set off the charge.
This way the pipe material and inside surface finish are not an issue (or less of one).
RE: Circuit to detect a pipe wall
Jeff
RE: Circuit to detect a pipe wall
RE: Circuit to detect a pipe wall
----------------------------------
If we learn from our mistakes,
I'm getting a great education!
RE: Circuit to detect a pipe wall
Absolutely, but also a lot more fun, reminiscent of dropping an M-80 firecracker into your neighbor's garbage can!
"Venditori de oleum-vipera non vigere excordis populi"
RE: Circuit to detect a pipe wall
pipe, you could use a Hall effect sensor to detect the
pipe end. I am not sure how the ring magnet would be affected by the high temperatures, though.
RE: Circuit to detect a pipe wall
I would suggest, from a redundancy standpoint as mentioned earlier by others, that you use 3 or 4 "wisker" type switches, somewhat trailing the plug at angles and held closed by the pipe walls. Then set up a voting method of detection by requiring 2/3 or 3/4 switches to be open for ignition, helping to eliminate false ignition from movement of the plug inside the pipe.
"Venditori de oleum-vipera non vigere excordis populi"
RE: Circuit to detect a pipe wall
wrapped in a layer of asbestos.
RE: Circuit to detect a pipe wall
RE: Circuit to detect a pipe wall