Which type of actuator fits the job

[Guilty Spark]

Ok, maybe not actuator.. I need to decide between two types of solenoids? Not 100% on what they are called but i'll try to get the gist of it across.

I want to be able to be able to build a system where a piston strikes a mechanism in a linear motion, and I am not sure if air or electric ones are more suitable.

Conditions:
-The piston must be able to hold up after striking for long amounts of time
(electric can overheat I have heard?)
-Must be able to "rapid fire" as well, not sure which is better for this
-Noise and clicking minimized
-Longevity of the actuators
(air more reliable?)

-Velocity control is a bonus, but open for debate if anyone has any experience

The pressure required is maybe a hard tap on a surface by your finger, not talking tons here.
Throw distance not more than 1", so a quick return may be possible without springs which satisfies the noise requirement I am thinking..


Any help is appreciated, I am looking to get advice before just blindly wasting more money here. :)

 

[Guilty Spark]

Ok, a more direct question to get us started... does electric have a faster response time.

Taking into account that I am going to be using micro pneumatic cylinders with a very small throw distance, is there going to be a problem with delay compared to electric?

 

[Guilty Spark]

You have:
A) A coil that is charged electrically propelling a mass of iron (the piston) using magnetic repulsion to move it.

or

B) A pressure differential (negative or positive- not sure if it matters) on one side of the piston, held back by an electric valve, with a small airline attached to make it move.


Assuming the the electrical signal and an air valve are opened at the same time, does the air piston strike the mechanism at the same time or slightly later?

 

[Jobrag]

For you "rapid fire" requirement could you use several solenoids set to fire slightly after each other to give a roll effect?

 

[Guilty Spark]

Cost would be a huge problem with that, the project is for a piano that is computer controlled.

So.. yeah. 88 keys, 88 solenoids already. Multiply that by two + the required hardware to drive them all. Owch. :D

Check this out, its probly the most taxing load id ever be able to put on it. What with the repetition etc etc. As long as it can handle that i'd be aces!

http://www.youtube.com/watch?v=nHBuKmyhbtQ&feature=related

 

[Jobrag]

How are you going to control the force on the keys?

 

[Guilty Spark]

Vary the voltage or vary the amount of air through the valve I think..

Im still weighing the choice of air/electric though, those challenges come later on.

 

[Jobrag]

Either of those would add a huge level of complexity needing analogue as well as digital outputs, have you considered piano lessons?

 

[Guilty Spark]

I have no musical talent lol, part of the reason for this project. Ill come up with something eventually.. just want to know which path to take so I don't waste time on the wrong one.