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Assistance with Folding Mirror Project

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TunerMax

New Member
I found some very helpful threads that were similar. I do apologize in advance, like many posters, my electrical knowledge pales in comparison to most of yours. Which is why I'm here looking for help

here's one thread that is the most similar to my circumstances:

http://forum.allaboutcircuits.com/showthread.php?t=7703


With my situation being different, I was unable to get my answers from the other threads.

This is a long Post, I didn't want to leave anything out, so bear with me to get this started



Here's what I have going on:


I have 2 folding mirrors, the DO have built in limit switches (current switches I think actually but it's not important).

This was good news to find out because it simplifies my wiring.



(I will be uploading the diagrams I've roughly drawn up as soon as I'm home, I cannot upload from this computer)


I have an OEM folding mirror SWITCH too, but no diagram for it so I had to test it out. It seems the following is true for it:



Terminal 1 = Output to Mirror Motor (+/-)

Terminal 2 = Output to Mirror Motor (+/-)

Terminal 3 = Ignition Power +

Terminal 4 = Constant -



There are 3 switch positions with no spring return to neutral. One is FOLD OUT, one is FOLD IN, and then NEUTRAL

Obviously FOLD IN and FOLD OUT alternate consistant power/ground out to the Mirror Motor terminals. And Neutral seems to be isolated completely, this was good news also.



So now you know what I have for a SWITCH and for an OUTPUT already. Here's what I want to acheive:



When I press the LOCK button on my Key Fab, the mirrors fold in.

When I turn the IGNITION to "ON" the mirrors fold out.



I plan to keep the Folding Mirror Switch in the NEUTRAL position at all times during the uses listed above. If it's left in either FOLD OUT or FOLD IN positions on the Folding Mirror Switch, then obviously I could have a Short due to reversing polarities. I plan to fuse/circuit breaker both outputs to the Motor as added protection of course.



What I've considered so far:



LOCK FUNCTION (FOLD IN):

Using a N.O. Latching Relay for the LOCK function. This would allow me to press the LOCK button only once (pulse) but have the mirrors fold in all the way. The issue with this is I don't know how to RETURN the Relay to the N.O. position, I'd assume that I need to run another trigger from the IGN "ON" relay to trip it back to N.O. state BEFORE it sends power the other way. I also though about using a NOTO Relay with a timer around 10 seconds for this function. Unsure if this is best?





IGN ON FUNCTION (FOLD OUT):

This one I'm kind of lost on. At first it seemed simple, a standard SPST relay should work, but this poses an issue with the normal "manual" function of the switch. If the key is in the "ON" position, then the Folding Mirror Switch is powered also. This is an issue I'm not sure how to overcome, because the Folding Mirror Switch is a fairly sealed unit.



Before I suggest ideas on overcoming this, I will rather humble myself, and put it to your suggestions. You likely have a much better and simpler Idea for this issue than I.



To sum up, my issues/questions:



LOCK (FOLD IN) FUNCTION: Need to determine the proper/ideal "latching relay" or "timed/holding" relay, or other suggestion to control pulse signal. Is a NOTO SPST relay with about a 10 second time best?



KEY "ON" (FOLD OUT) FUNCTION: Running a standard SPST relay for this AUX function poses an issue with the normal "manual" function of the switch. If the key is in the "ON" position, then the Folding Mirror Switch is powered also.



I found 1 unit that seems it may work for both functions, but I'm unfamiliar with it:

http://www.smarthome.com/7279/Delay-Timer-Relay-ELK-960/p.aspx



And also a bunch of wiring options here, but I'm kind of unsure which suits my application best, if any:

http://www.the12volt.com/relays/page5.asp#ctm



Of course, your help is very much appreciated. I was hoping to finish this project this weekend, but this electrical hurdle has me scratching my head.



Thanks in Advance guys!
 
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alec_t

Well-Known Member
Most Helpful Member
If you have limit switches you probably don't need timers or latching relays. Time-control of mirror movement is difficult because the duration depends on whether the mirror moves freely or sluggishly (e.g. may be weather-dependent).
 

TunerMax

New Member
Good call about the timer duration, 10 seconds should be plenty regardless of the weather though. that's a LOT of time for a pair of mirrors to fold in.
5 seconds could be too little.
Once the mirror is done moving the power will still be supplied still, that's cool because the mirror's limit switch will just cut the circuit. Then when the timer stops, the power delivery stops.

And if the motors need more time they'll have the power there still to move until the stop (limit)

The reason for the latching relay is because the LOCK function only sends a pulse signal. And the reason for the timer is because if it doesn't disconnect again before the Manual switch is operated, or the Key is turned to "ON" then the polarities will reverse, causing a short.
 
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