Need a very simple light switch.

marshallf3

Joined Jul 26, 2010
2,358
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I work for a living, posting in here is just a hobby to try and help some people out as I can when I have spare time on my hands. If the Senior VP of the corporation I work for needs something done it obviously takes precidence, or if something breaks I have to handle it. I also have a lot of projects going on that are work related I have to tend to.

Sorry it took so long, just some discussion as to why I'm opposed to spending $84,000 with one firm on upgrading part of the warehouse lighting when my approach will produce the same results for less by going at it in a different manner.

In addition to being part of the upper management team I'm also responsible for many of the physical operations of this 1/4 million square foot building as well as some other property that we own. I've been working from home most of this week thus I can devote a bit more time to this forum.
 

marshallf3

Joined Jul 26, 2010
2,358
Hmm. If I do as you say, wont I then have a light activated device?

I want the device to do as followed:

When I push a "push and release" button a motor will start, because light is comming from a LED and hitting the phototransistor. When there is no light between the LED and transistor ect. a piece of carton, the motor will stop, as will the LED. If the LED doesnt stop, the motor will start up again as soon as I pull out the piece of carton, that I used to stop the light from passing to the transistor and that isnt what I want.

Ive made a new drawing. Will this work?
OK, so I see you also want this to latch in the "no run condition" once it has stopped, and not start up again until you manually push a button to tell it to? Simple enough to modify but please clarify this a bit more. Actual "real world" examples might help.
 

Wendy

Joined Mar 24, 2008
23,415
You're over complicating it quite a bit. A LDR is a variable resistor, which light it is around 100Ω, with dark 100MΩ.

The transistors and 555 are simply to make it into a switch. The LDR is a sensor, but it is not a switch.

Are you wanting to activate a relay according to light/dark?



Speed is not an issue. They are fast enough to leave humans behind.

Do not eliminate the diode on the relay. It is needed to keep the relay from blowing the other electronics.

Were you wanting an LED indicator? It wasn't clear to me.

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marshallf3

Joined Jul 26, 2010
2,358
I'm waiting for some real world examples, sounds like it may have something to do with a conveyor line.

It started out as when no light passed from Point A to Point B a motor stopped. Now I think the requirements include the motor staying stopped until an inspection can be made as to why it stopped. We're just still a bit short on info at the moment but, if properly explained with some sort of real world example(s), it should be easy enough to acomplish.
 

Thread Starter

Jacob J

Joined Jun 18, 2009
159
Thank you all for your help, I really appreciate it!

Okay first of all, let me tell you a bit more about the project. It is a powder dispenser for reloading ammunition. I saw this video and thought it would be very simple to build (I am naive, but still..). http://www.youtube.com/watch?v=oFuJqrNH9BQ

I need to control the light source that activates the phototransistor. I will place the phototrans. in a tube, lets say an inch of aluminium tube. The LED will be lined up with this tube and when a piece of paper is placed between the LED and phototrans, the phototrans inactivates, wich causes the motor and the LED to stop. I would then have to push a button to make the LED start again, because if I take the tray of the beem scale, the paper disapears, wich would cause the phototrans. to activate and the motor turns on and I have powder all over the place.

So the button and the controlling of the light source that activates the system is very important. I want to be able of controlling the motor speed with a potentiometer so I can finetune the dispensing speed.

I hope you can see what I mean and sorry if my english is a bit rusty. I am from Denmark, so it is school english I am trying to pull off here;D
 

marshallf3

Joined Jul 26, 2010
2,358
So now we need to control the motor speed as well?

Back to the drawing board as they say, but my next couple of days are full. due to work projects I've been putting off and I have to have something to show for what I've done all week.

This thread is kind of lost already with far too many different specs, designs and changes. You might want to start a new one called automatic powder dispensing device or something.
 
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