# Astable linear solenoid?

1. Sep 15, 2015

### udtsith

I enjoy doing kitchen engineering with my kids. We were looking to do a robotics experiment which would require a linear solenoid actuator to continuously pump. I thought it would be simple until I realized that I would likely need a 555 chip(?) and some skills with circuitry...which would be fine if that was the lesson for me and my kids. Basically...anybody know where I might purchase a linear solenoid that is in the astable position. They seem surprisingly hard to come by? Thank you! Sorry this isn't an academic question.

2. Sep 15, 2015

### udtsith

Thank you Nidum. I was the one that posted to the original thread you site. After taking what you said from that one I did online searching on building a simple circuit but it would take me some time to figure out and experiment as I am on level 2 with circuitry. My interest is in mechanical motion. I'd like to learn circuitry but time and our exercise we are doing is on robotic motion. I went to youtube and there are some basic set ups but I find myself straining to see how they wired the solenoid. And then the online look up seems that using a 555 chip is the way to go. If I can get by with out having to do circuitry that would be great.

3. Sep 15, 2015

### Nidum

There is an alternative solution using a motor and crank to push and pull a rod continuously and at an easily controlled rate .

Simple model boat motors will be ok .

If you are interested in robotics then look into simple stepper motor applications . Much of what you would need for experimentation can be bought ready made and there is an easy road to computer control .

4. Sep 15, 2015

### Nidum

5. Sep 18, 2015

### Baluncore

Time delay relays are old technology. You can make an astable solenoid by including a big lump of iron in the magnetic path. It takes so long to magnetise and demagnetise the core that the solenoid switches very slowly. A relay contact on the solenoid can be used to sense the state and power the coil when the solenoid gap opens.

A magnetic time delay relay can control the power to a larger solenoid. A flyback diode can be used to adjust the symmetry of operation.
What period of operation do you want for the On and for the Off states ?

6. Sep 19, 2015

### JBA

How you want to apply this solenoid- pump combination?
Is it to provide a continuous flow or more like a plunger to cycle something connected to the end of a liquid filled tube?
If you want something that will simply provide a liquid/gas flow; then, have you considered using a standard electric micro pump?
There are a variety of small diaphragm liquid and gas pumps available on line with a wide range of delivery rates and operating voltages.