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Topic: Control DPDT button with Relay (Read 4055 times) previous topic - next topic

rickburgen

How do I wire up a relay to control a DPDT button, I'm trying to bypass the actual button press and control it via software.

Thanks.

retrolefty

#1
Sep 17, 2012, 08:11 pm Last Edit: Sep 17, 2012, 08:13 pm by retrolefty Reason: 1

How do I wire up a relay to control a DPDT button, I'm trying to bypass the actual button press and control it via software.

Thanks.


You can't easily. As a DPDT button will have two of the contacts in a normally closed state you can't just wire a DPDT relay contacts in parallel with the button's contacts and get the same reaction as the button pushes as your relay contacts won't force open the button's normally closed contacts. You can totally replace a DPDT button with a DPDT relay, but you can't have them work properly in parallel where either can control the circuit.

That make sense?

Lefty

rickburgen

Thanks for your reply. It makes sense, and thats what I had thought. Is there a way I can bypass the button with out a relay?, maybe just two output pins that are both high?

retrolefty


Thanks for your reply. It makes sense, and thats what I had thought. Is there a way I can bypass the button with out a relay?, maybe just two output pins that are both high?


How about a servo to mechanically operate the button?

Lefty

rickburgen

Nah, I am overriding the climate buttons on my car. So having all those servos would be a pain. Any other work arounds?

rickburgen

I just reread our dialogue, I think there might be some confusion. The relay isn't DPDT; just the button is. Does this change anything?

retrolefty


I just reread our dialogue, I think there might be some confusion. The relay isn't DPDT; just the button is. Does this change anything?


No.

cyclegadget


Was the button checked to see if it is normally open, or normally closed on both poles? The come either way or even one pole NO and the other NC. It just depends what it is used for.
 
Good links: Eagle tutorial= http://www.youtube.com/playlist?list=PLDE1858BD83D19C70
General Arduion tutorials = http://tronixstuff.wordpress.com
http://www.gammon.com.au/forum/bbshowpost.php?bbtopic_id=123

rickburgen

How do I check a dpdt switch? My multimeter doesn't have the continuity test.

cyclegadget


  It requires a the rest of the circuit to be complete with load and power but....

In the right conditions, a open switch will have voltage across it, and a closed switch will have nearly 0 volts across it. That only works with the rest of the circuit complete.


Here is a step by step example: http://www.wisc-online.com/objects/ViewObject.aspx?ID=DCE1102
Good links: Eagle tutorial= http://www.youtube.com/playlist?list=PLDE1858BD83D19C70
General Arduion tutorials = http://tronixstuff.wordpress.com
http://www.gammon.com.au/forum/bbshowpost.php?bbtopic_id=123

rickburgen

This is the board I am dealing with. Red are the dpdt buttons.




I am using the following image as a guide. Does this show a NC circuit? But either way, would I have to connect my multimeter to the terminals in the middle?



cyclegadget


It looks like all three switches are connected a little differently. At least to of the switches seem to be linked to each other. The only way I would go further, would be with an Ohm meter and some thorough testing. I hate to tell you something and have it go wrong, there is a lot of ways to make a mistake trying to connect to those switches.
Good links: Eagle tutorial= http://www.youtube.com/playlist?list=PLDE1858BD83D19C70
General Arduion tutorials = http://tronixstuff.wordpress.com
http://www.gammon.com.au/forum/bbshowpost.php?bbtopic_id=123

rickburgen

I did eventually test it today. And came to the conclusion that they are NC switches, with help from the netduino community and cyclegadget, I have removed the buttons from the board.Now I need to figure out how to connect them to my n+/arduino(I havent deceived which I'll use) via a reed relay. Any suggestions?

kizzap

If I am understanding your question correctly, then what you are trying to do is possible. The only caveat I will add to that is that it is dependant on the type of switch and how it works internally.

Check the picture I attached for a Schematic.

Kieran

rickburgen

I found that the switches are NC.

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