so i want to build a hoop that small pellets can fly through.
if a pellet does go through the hoop a light / buzzer goes off as well as maybe some other processing.
what does /g/ recommended? I know im going to need some kind of motion sensor but i had a look online and dont really know much about the subject
>>51927056
If you can make the pellets and the ring out of metal you can measure the induction current and not only determine if a pallet passed through the ring but the velocity as well.
>>51927056
I assume you can do this by just measuring if current changes.
>>51927081
they could be made out of metal. how would i go about that and would it be costly?
all the pellets are going to be fired at a constant speed so the velocity shouldnt matter. more accuracy than anything else
shameless bumpin
>>51927099
https://en.wikipedia.org/wiki/Electromagnetic_induction
If they move with constant speed it would better if the pallets were magnetic. It's pretty straight forward: Take the ring, cut a small part out of it, measure current between. The change of the magnetic field will induct a current in the ring. That's one of the Maxwell laws.
>>51927056
Is this for an air rifle / airsoft or pellet gun?
Try /diy/
>>51927147
if a pellet flew past the outside of the ring closely, would that not effect the state though?
>>51927056
what kind of pellet? does how big are they relative to the hole? are they a particular material?
if they're consistantly barely fit through the hole, you could use a simple switch like pictured, otherwise perhaps something like a photoresistor+led sensor
>>51927226
forgot picture
>>51927195
of sorts. very low powered though
>>51927226
this is still to be determined though i would say the ring is going to be much larger than the pellet
>>51927225
No, there shouldn't be an effect if the pallet flew close to the ring. But keep in mind that the inducted current depends on the pallets velocity, if it is too slow it might be difficult to measure due to noise (the ring acts like an antenna and depending on size and direction might pick up certain frequencies).
>>51927291
should have probably mentioned it is going to be mounted on a drone. i guess the movement would effect this setup?
>>51927312
It might but not very much, the relative velocity of the pallet to the ring is important. I assume the pallet is much faster then the drone at max speed, if so should be no problem.
>>51927312
if there's no strict requirement for it to be a hole, why not a panel made of cloth or something, attached by 3 points, with one point attached to a switch? (that is, pressing on the cloth pulls on the attached points)
>going to be mounted on a drone
really bad idea. pellet hitting the blades is gonna be a catastrophe and putting anything over the fans that won't allow a pellet to go through will also have a big effect on the air flow.
>>51927056
tachometer and micro controller - bit glitchey but who cares -done
>>51928986
Programmable
Logical
Controllers
>>51927056
Inductive proximity switch, perhaps. I use them all the time at work but I have no idea how capable they are of triggering at the speed of your projectile. You may need to mount several of them in the diameter of the hoop.
>>51927056
What about this: mount a photo transistor behind a light blocking film such as black construction paper.When the pellet tears through the paper, the light passes through and is detected by the transistor. You could probably flood the area of the hoop with strong IR light to overcome the variables of regular daylight.
the problem with a metal pellet + a coil, especially mounted on a drone, is that the induced current from the pellet would be very small. It'd have to be sensitive as fuck and I don't know if all the electronics on the drone itself would make it impossible to detect. Do your maths first to see what kind of current you'd expect from the interaction.
Most motion detectors work in a line. Your other option is something like a high speed camera that you can set up to detect bright yellow airsoft pellets or something like that.
>>51931589
The pallets would have to be magnetic, there is no way the magnetic field of moving charges that slow create strong enough magnetic field parallel to the ring normal to induct a current that is measurable.
