Filling machine

I'm working on a school science project that makes a machine to weigh and fill pasta. I can build a scale using a load sensor but now i have to control an arm/ flap that will quickly close when the weight reaches a pre determined weight to stop the flow of dried pasta elbows I'm thinking have the pasta on a decline slide and once the arduino detects the preset weight, the flap quickly closes down. I'll have a button to press to allow it to flow again.

Question is, what kind of parts do i look for to open and close this flap quickly? It's going to weigh half a pound at a time most likely. Has to be fast because if it takes too long then too much time will lapse between the sensing of the right weight and closing of the flap so it will allow extra weight through

I think you have to design the mechanical parts and actions before you can consider how to make and Arduino do something with it.

Paul

Seems like a rather challenging mechanical problem.

What happens when pasta gets trapped by the flap and prevents it from closing?

Some stores in my area offer bulk nuts/pasta/grains and have what appear to be carefully engineered dispensers with sliding closures or even measuring paddle wheels, operated by hand.

They are available in several different designs, like this or this so you might look at some for ideas. Google "bulk nut grain dispenser" to see others.

Does it have to be a flap? Wouldn't the forceful closing smash some of the product? What about a conveyor belt which drops pasta off the end? When preset weight is reached just stop the conveyor. If you have speed control you could slow the conveyor at a certain point and trickle in the last few weight units.

I agree that a flap is going to be difficult because of the "lumpy" nature of pasta.

What about putting the pasta in a jar and rotating the whole jar (mounted approximately at its balance point) so that the pasta pours out and the flow can be stopped by bringing the jar back to the upright position.

Another option might be to have the pasta flow down a slide and have the ability to raise the slide to the horizontal position (or a little more) to stop the flow.

I suspect a servo would be very suitable for providing the motion.

...R

Welcome to the world of food engineering - a world much more challenging that manufacture of mechanical components.
“Diversion” is probably the simplest method of cutting off flow into a measuring hopper.
When the optimum weight is reached have a paddle divert the feed away from the measuring hopper. That way you aren’t trying to close a gate against a rigid but fragile product. Once you have diverted the flow you either recycle it back to the bulk feeder, or switch off the feed system.

Here is a video of what @dougp maybe thinking of. A pretty simple design.

https://www.youtube.com/watch?v=Ak31bujvL_M

justone: Here is a video of what @dougp maybe thinking of. A pretty simple design.

Yep. Good find!

justone: Here is a video of what @dougp maybe thinking of. A pretty simple design.

I can't see how the flow is being controlled

...R

Robin2: I can't see how the flow is being controlled

...R

The flow from the conveyor falls into the cup on the scale. Scale runs conveyor motor 'til setpoint is reached. The conveyor is fed by a bulk hopper, at the rear, which feeds product as the conveyor pulls it out from under the hopper.

You will notice that at the very end of the rotating cycle (look at the "teeth") there is a very small amount of

movement to get to the set point.

dougp: The flow from the conveyor falls into the cup on the scale. Scale runs conveyor motor 'til setpoint is reached. The conveyor is fed by a bulk hopper, at the rear, which feeds product as the conveyor pulls it out from under the hopper.

That was not obvious to me - it seemed that the operator was just holding the cup under the outlet.

...R