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How to get a linear actuator to open & close a door & switch a relay at the end of the stroke so it reverses direction Answered

 It would be simple with a manual relay switch but  I don't want to have to be there to throw the switch. I want a timer to do it each morn and eve so the door opens at one time then next time timer comes on it closes. The Linear actuator has limit switches to stop the motion at the end of the stroke.
I need the next time it powers up to reverse motor direction. 

Also will need to get power from 110v timer switch to 12v power supply to the LA   

Also if it is powered from the timer I use now to power the lights, they will stay on for 2 hours then off. So the relay must not send power back right away but delay until the power goes off and the next time it powers up then send it to the LA.
Or I need a separate battery power source and timer that will just give power long enough for one stoke then off. Not sure how to do that.
Any electrical wiz kids out there can help me with this?

Discussions

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steveastrouk

Best Answer 7 years ago

Start with a circuit like this - three relays. When the lower left relay is OFF the door opens, when its ON the door closes. Or possibly theother way round.

Hen door relays.jpg
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nowrydellsteveastrouk

Answer 7 years ago

Question for you. I have one actuator to move door. How would I use 2 switches to both control open and closing? Would I need relays? And what kind of switches. The problem im having and someone suggested I get a dual latching coil relay and 2 dpdt rocker switches. But I think its gotta be wrong. I want to simply open or close the door from either side of it. One switch is easiy, but 2 seems to have people stumped. Please help

http://youtu.be/MTFbkoSJGtY

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Wellthmakersteveastrouk

Answer 7 years ago

Thank you for your help. Would you mind helping me with a brief explanation of why 3 relays?
What does that accomplish and what operates the relays?
Thanks.

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steveastroukWellthmaker

Answer 7 years ago

The limit switches in the actuator are not usually designed to handle the current that the motor in the actuator needs. Two of the relays handle the motor current and direction changing, the other decides which is required - open or closed.

Steve

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Wellthmakersteveastrouk

Answer 7 years ago

That is what I thought. I just did not understand how it would work,. I don't have any electronics understanding.
Thanks I will see if I can get parts and give it a try.

Thanks

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steveastrouk

7 years ago

@NowryDell

Easy.

Use my circuit, and switch the lower relay with a 2-way switching circuit - the way you run the lights on your stairs, or down a hall. You need an SPDT switch on each side of the door.

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nowrydellsteveastrouk

Answer 7 years ago

Can I salvage the dpdt's by using just one side? Or do I need to eat those til later use? Do I still use the relays? and just remove the timer and relay from the schematic? If you could draw something up it would be appreciated greatly

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steveastrouknowrydell

Answer 7 years ago

Sure, the switches are still fine !
You need the relays.
Just remove the timer, andtreat the lower left relay like its a lamp.

I'll try and show you the circuit later.

Steve

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henwaysteveastrouk

Answer 7 years ago

Hi there, I have a slightly different project where I am using a plug-in digital timer. I have torn apart the timer and found the relay in it.
http://www.amazon.com/Stanley-31200-TimerMax-Indoor-Digital/dp/B0020ML744/ref=sr_1_14?ie=UTF8&qid=1326940132&sr=8-14

http://www.shori.com.tw/product_detail.asp
S3-12-A
Since it is only SPST (SPNO) all I think I can use is the "open" and "closed" circuit.
However, I need to have it actuate a DC one direction for "closed" when the timer turns on, and then I need it to actuate the DC motor the OTHER way when it turns off. I will of course put in limit switches.
I am only closing a window and will use a 2.4V cordless screwdriver attached to a screw drive.
I am really bad with relays! But I did at least figure out which pins were NOT connected to the AC!

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steveastroukhenway

Answer 7 years ago

If you use the circuit I've shown, your SPNO relay will work just fine.

Steve

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henwaysteveastrouk

Answer 7 years ago

I appreciate your input, but these SPNO relays are by design with only 4 contacts. Looking at the above diagram I don't understand how to work that.
I "should" have 12VDC in there to operate the single relay and hopefully I can use that power for the other 2 relays.
Sorry to ask you to spoon-feed me the information, but I don't know how to square your diagram with what I will have!

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steveastroukhenway

Answer 7 years ago

Your timer replaces mine. Its that easy, ;-) Connect the contacts of your timer between the bottom left contact of the bottom left relay and ground !!

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nowrydellsteveastrouk

Answer 7 years ago

Ok, can't seem to match the relay number with Radio Shack. So, when you have a free moment to go into more detail let me know

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steveastrouknowrydell

Answer 7 years ago

Take a look at these
http://www.radioshack.com/product/index.jsp?productId=2049722&numProdsPerPage=60

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lemonie

7 years ago

I've got some switches that you might use. But I'm only paying UK postage.
See picture.

L

t.JPG