Pages: [1] 2   Go Down
Author Topic: Control DPDT button with Relay  (Read 3329 times)
0 Members and 1 Guest are viewing this topic.
0
Offline Offline
Full Member
***
Karma: 0
Posts: 117
oh H4x!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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.
Logged

Left Coast, CA (USA)
Offline Offline
Brattain Member
*****
Karma: 331
Posts: 16518
Measurement changes behavior
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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
« Last Edit: September 17, 2012, 01:13:24 pm by retrolefty » Logged

0
Offline Offline
Full Member
***
Karma: 0
Posts: 117
oh H4x!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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?
Logged

Left Coast, CA (USA)
Offline Offline
Brattain Member
*****
Karma: 331
Posts: 16518
Measurement changes behavior
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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
Logged

0
Offline Offline
Full Member
***
Karma: 0
Posts: 117
oh H4x!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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

0
Offline Offline
Full Member
***
Karma: 0
Posts: 117
oh H4x!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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?
Logged

Left Coast, CA (USA)
Offline Offline
Brattain Member
*****
Karma: 331
Posts: 16518
Measurement changes behavior
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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.
Logged

Greenville, IL
Offline Offline
Edison Member
*
Karma: 11
Posts: 1309
Warning Novice on board! 0 to 1 chance of errors!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset


 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.
   
Logged


0
Offline Offline
Full Member
***
Karma: 0
Posts: 117
oh H4x!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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

Greenville, IL
Offline Offline
Edison Member
*
Karma: 11
Posts: 1309
Warning Novice on board! 0 to 1 chance of errors!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset


  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
Logged


0
Offline Offline
Full Member
***
Karma: 0
Posts: 117
oh H4x!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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?


Logged

Greenville, IL
Offline Offline
Edison Member
*
Karma: 11
Posts: 1309
Warning Novice on board! 0 to 1 chance of errors!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset


 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.
Logged


0
Offline Offline
Full Member
***
Karma: 0
Posts: 117
oh H4x!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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?
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 1
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

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


* arduino relay.jpg (62.73 KB, 1514x839 - viewed 21 times.)
Logged

0
Offline Offline
Full Member
***
Karma: 0
Posts: 117
oh H4x!
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I found that the switches are NC.
Logged

Pages: [1] 2   Go Up
Jump to: