Relay to Solenoid Challenge

[tmitchell]

I"m a student learning electrical and motor controls and created a challenge for myself but am stuck. Here is the challenge:


Challenge 1
A) Using a blower (compressed air) set to a min level so that it would keep the light bulb from turning on. No air or falls below the min level, and fail the light comes on.



Challenge 2)

B) Using a blower for 10 seconds followed by a vacuum for 10 sec then alternating back and forth to again keep the light bulb from coming on. Think check engine light dont want to see that light come on.


At any point if there is no air or suction the light would be set on a 5 second delay before coming on. Same would be applied if the air or suction is not strong enough. Not worried in this example about to strong just if it generates enough or hits the min. In other words it has to hit a min or the light would come on, but nothing would be setup for max.



Here is how I thought I could accomplish this.

1) Using plastic tubing connected to a shop vac that could provided compressed air or suction.
2) This would then enter a 3 way control valve / pneumatic solenoid. This is hooked up to a toggle switch that would move it from normally open to normally closed for challenge #2.
3) From there it would travel to a pressure switch that could set the min amount of pressure or suction to remain open.
4) If not any it closes then the delay relay would be activated, and after 5 seconds would turn the light bulb on.

Challenge 2 would move the toggle switch from only the blower to both blower and vacuum with the delay relay connected that would be set to alternate.



I know lots of things to change to make this work, so give me your thoughts as I learn more.

 

[betwixt]

I would approach it from a completely different angle. Use a pressure sensor with digital output, and an MCU to look at the timing requirement and to provide the signal to turn the light on.

Its a more flexible solution that answers both challenges with the same hardware and also lets you set the pressure thresholds it operates at.

Brian.

 

[BradtheRad]

Your solution appears workable. I guess you have the advantage by being familiar with industrial-grade equipment?
Reading the first challenge I pictured a simpler arrangement, say a ventilation fan. Attach a flap of paper to be lifted by the breeze, so it allows light to reach an optical sensor. Whenever the fan shuts down, the flap lowers, blocking light to the sensor. A simple amplifying circuit activates the relay which turns on the bulb.

To create a few seconds delay, the propeller slows down gradually, letting the flap drop slowly. Adjust things so you get the desired five seconds.