Automating a crystal cleaning procedure?

[excalibur313]

Hi Everyone,
I have a little experience with electronics, but I wanted to get your advice on a project I have. I want to make a circuit that would automate the following:

Apply a high signal (say +5V) to a pin on a pump to turn it off
Interface with an electronic power supply (RS232) or just output 0-3A current (with a corresponding 0-10V) for 20 min (to heat a sample)
Turn a knob X turns to a certain position on a valve (Ideally this would be double checked against a high trip line (say +5V) to reproducibly leak in the same amount of a gas, but that is optional)
Somehow apply a series of button pushes to a 2x2 array of 0.5"x0.5" buttons (has to be done mechanically unfortunately)

After waiting the 20 min everything would be reversed to turn it all off. This is done exactly the same way every time Do you think I could use a micro controller for something like this or what would be the best way to approach this project?
Thanks!

 

[crutschow]

It sounds like a job for a micro controller.

But generating the mechanical forces to turn a knob and push buttons, will require some interesting (read difficult) electro-mechanical interfaces. Can't you break into the system to use a servo valve and make the button switch contacts electronically?

 

[excalibur313]

Thanks for the quick reply! After thinking about it more, I might be able to break into the system to give high signals to override the buttons that need pushing, but it just makes me nervous since the electronics is pretty expensive (like $10K) and I don't want to screw it up. I wasn't sure if they just made mini solenoids something similar that could work here.
As far as turning the valve, it would have to be done mechanically. I am including a picture of what I am talking about:
**broken link removed**
You are turning the valve on the right while it is bolted onto a big vacuum chamber. Is my best bet to get a nerdkit and go through it that way (ATmega328P micro controller) or what is the best way to select a good microcontroller? (I used a 68008 a few years ago for an electronics class I took, but there might be better ones to use here.)

PS- Do you think that maybe a better method for outputting the 0-10V, 0-3A would be just to regulate what is allowed to go through the power supply I already have? ie if controlling the power supply itself is too hard, I could just have a regulator downstream that just would cut the power appropriately.

 

[ronv]

Hi Everyone,
I have a little experience with electronics, but I wanted to get your advice on a project I have. I want to make a circuit that would automate the following:

Apply a high signal (say +5V) to a pin on a pump to turn it off

What turned the pump on?

Interface with an electronic power supply (RS232) or just output 0-3A current (with a corresponding 0-10V) for 20 min (to heat a sample)

Is this a heater? How do you know what to output? Temperature or watts or???
Turn a knob X turns to a certain position on a valve (Ideally this would be double checked against a high trip line (say +5V) to reproducibly leak in the same amount of a gas, but that is optional)

It looks "big" could a stepper motor turn it? What do you mean by a high trip line?

Somehow apply a series of button pushes to a 2x2 array of 0.5"x0.5" buttons (has to be done mechanically unfortunately)

This is like a computer keypad?

After waiting the 20 min everything would be reversed to turn it all off. This is done exactly the same way every time Do you think I could use a micro controller for something like this or what would be the best way to approach this project?
Thanks!

You must be a mechanical engineer if you are worried about the electronics and not the mechanics. :=)

Good Luck and have fun!

 

[excalibur313]

Hi Ronv,
After looking into it, it appears that the pump requires a total of 4 pairs of pins that need to be shorted upon startup (only done once) and closing 2 additional pairs of pins actually will turn the pump on and off.

The power supply is for a heater so it is normally just attached to ground. I normally output a particular current while letting the voltage float between 0-10V. (Typical currents range from 0.5A to 2.5A) I have no idea what the temperature is (unfortunately) so we don't have to worry about anything there.

What I meant by a high trip line is that turning the valve open leaks a certain amount of gas into a chamber that is detected by a pressure reader. I want to leak a certain amount of gas in which almost always corresponds to a certain number of turns of the leak valve. I thought it could be cool to have a check in place so that I could trigger the pressure reader to trip when above a certain pressure. I believe they have a relay built right into the reader, but they also have a pin that outputs a voltage that corresponds to a particular pressure so alternatively I could probably build some sort of trip.

After thinking a bit more about triggering these buttons, I think I might be able to use a servo with two rods pointing toward the buttons. When rotating CW it would hit the top button and when rotating CCW it would hit the bottom. This doesn't seem so bad in theory, but since I am neither a mechanical or electrical engineer, but a physical chemist I clearly am shooting in the dark a bit here.

I was thinking about maybe getting one of the Arduino setups. Does anyone have experience with those?
Thanks again!