# Solenoid Operation

I’m looking at using a solenoid in an upcoming project, in particular the small 5v one. The trick is I want to initially have the solenoid depressed physically by an object until that object is pulled upwards, then I’m hoping the solenoid will pop out and remain under the object which will now be under spring tension. On command the solenoid will withdrawn and the object will pull inwards and do its job. Does this at all sound possible using a solenoid setup?

Hi Jake,

From what you have outlined in your post a solenoid sounds like a very good choice.
With the small 5 V variant the strength of the pull will depend on the current being passed into the actuator (the datasheet specifies a maximum of 1 A). The strength of the push is dependent on the spring and also relies on the pull strength.
If the object is super light this shouldn’t be a concern, although if you are looking to move a heavier object I would do a free body calculation to determine the forces that you require.

If you find that a solenoid is not able to provide the forces you need I would have a look at linear actuators.

Cheers,
Liam.

Hey Liam

I’m more concerned with downwards pressure on the solenoid post, initially the post would depressed because of the presence of the object and once the object is pulled upwards the solenoid post will extend simply because of the spring tension. From here the object will provide downwards force because it’ll now be under spring tension and the solenoid will stop the object from snapping back down. I’m worried the solenoid post under this downwards pressure from the object will struggle to still operate.

Cheers

Jake

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Hi Jake,

The force that a spring provides is roughly based on how far it’s stretched. Once the gravity force of the object and the spring are in equilibrium the solenoid will be able to disturb that, hopefully moving the object down.

From my understanding the solenoid you are looking to purchase is something like this.

I’m sure other users would be happy to do some calculations if you provide the info.

Cheers,
Liam.

Ah so I might need to clarify that the solenoid will be facing in a horizontal direction, so the downward force is side to side force.

Cheers

Jake

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Ahh ok, Yea this might complicate a couple things, I guess the main factor is still how much your object weighs, the frictional force caused by its weight will determine the amount of force required to make sure that it moves, is it possible to get some additional information so that I can help you further?

If there is a way to lubricate the plunger-object contact point that may allow for this one to work.

Cheers,
Liam.

The design is to have a blade that releases to cut a wire. The object wouldn’t weigh much but I’m assuming the force applied from the spring tension is more of the concern. I’m not stuck to a solenoid for the design I just thought it was more practical given the package size (small). It might be a case of getting a solenoid and seeing how it goes. Plan is to run it all off the trinket with the solenoid power wired separately.

Cheers

Jake

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I would definitely jump in and give it a test!
I’m keen to see how your project goes!

Cheers,
Liam