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#1
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Remote Turn On - Low Voltage Trigger Problems
Bah. I just got off the phone with the guys at PAC and they had some bad news for me. Turns out on the new GM cars (I have an '03 Alero) have a voltage drop in the speaker wires when the volume reaches a certain point. This drop falls below the .8V that low voltage triggers pick up. So, unless I can find a relay that will boost a very very low (not sure how low the voltage drops to) voltage to above .8, I'm SOL. The whole thing with me wanting the trigger and the speaker wire was to keep RAP. Now, unless I can find a relay that will boost that voltage looks like I'm going to loose RAP. Anyone know of a relay that will do this? -- jiffy ------------------------------------------------------------------------ jiffy's Profile: http://www.caraudioforum.com/vbb3/me...p?userid=33416 View this thread: http://www.caraudioforum.com/vbb3/sh...d.php?t=216358 CarAudioForum.com - Usenet Gateway w/over one million posts online! |
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#2
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I have to ask: why are you using a special remote-lead adapter instead of just finding a +12V source? Is it a leased car or something? MAY I MAKE A BETTER SUGGESTION THAT MAY BE LESS COSTLY AND PAINFUL? Anyway, I used to just do the following to provide a turn on lead from a factory radio: 1. Remove factory radio and test for ACC (radio switched wire, 12V) and attach a remote wire, OR 2. Remove factory radio and test for power antenna wire and attach there OR 3. Find the switched wire at the power antenna and run to the amp OR 4. Just run a remote lead to the fusebox. If you want to be sloppy/lazy, you can just put the bare end of the (small gauge) wire around one of the 12V switched (radio, etc.) fuse legs and push it back in. OR 5. Get desperate for a +12V ignition wi search under the dash and start testing connector wires until you find 12V that goes off with the key. Oh, and use a voltmeter, not a test light! Guaranteed to be successful eventually, even in big rigs or boats (yes I have done it in both) Good luck.... Marty -- MartyMcLeod ------------------------------------------------------------------------ MartyMcLeod's Profile: http://www.caraudioforum.com/vbb3/me...p?userid=34271 View this thread: http://www.caraudioforum.com/vbb3/sh...d.php?t=216358 CarAudioForum.com - Usenet Gateway w/over one million posts online! |
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#3
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Marty has a few good points... I had an alpine deck for a while in a
Civic and I really just couldn't be bothered to figure out what the problem was, but for some reason the power antenna lead wouldn't turn on my amplifier. What I ended up doing was running the remote wire from the amp directly into the same switched power (ignition lead) that runs to the deck. So whenever I had the car on (or just the key turned) was when the amp came on. Later on, I installed a toggle switch on that same lead making it so that I could turn the amp off at will (the cool thing with that was that I could still run the rest of the speakers and just turn off my sub if I wanted/needed to). Mister.Lull |
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#4
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That's why I put in #3,4, & 5. Always works, as there is always some type of +12V switched wire in a 12V vehicle. It's only a matter of finding one and connecting the remote wire. -- MartyMcLeod ------------------------------------------------------------------------ MartyMcLeod's Profile: http://www.caraudioforum.com/vbb3/me...p?userid=34271 View this thread: http://www.caraudioforum.com/vbb3/sh...d.php?t=216358 CarAudioForum.com - Usenet Gateway w/over one million posts online! |
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#5
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You could probably just build a circuit using a comparator to do it. More
components, but it should work if your resistors are right and you can get a fairly precise measurement of your voltages. On Tue, 26 Apr 2005, jiffy wrote: Bah. I just got off the phone with the guys at PAC and they had some bad news for me. Turns out on the new GM cars (I have an '03 Alero) have a voltage drop in the speaker wires when the volume reaches a certain point. This drop falls below the .8V that low voltage triggers pick up. So, unless I can find a relay that will boost a very very low (not sure how low the voltage drops to) voltage to above .8, I'm SOL. The whole thing with me wanting the trigger and the speaker wire was to keep RAP. Now, unless I can find a relay that will boost that voltage looks like I'm going to loose RAP. Anyone know of a relay that will do this? -- jiffy ------------------------------------------------------------------------ jiffy's Profile: http://www.caraudioforum.com/vbb3/me...p?userid=33416 View this thread: http://www.caraudioforum.com/vbb3/sh...d.php?t=216358 CarAudioForum.com - Usenet Gateway w/over one million posts online! |
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#6
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"jiffy" wrote in message news:1114549116.c4d58388c28583a8cbc16ca6796b5b09@t eranews... Bah. I just got off the phone with the guys at PAC and they had some bad news for me. Turns out on the new GM cars (I have an '03 Alero) have a voltage drop in the speaker wires when the volume reaches a certain point. This drop falls below the .8V that low voltage triggers pick up. So, unless I can find a relay that will boost a very very low (not sure how low the voltage drops to) voltage to above .8, I'm SOL. The whole thing with me wanting the trigger and the speaker wire was to keep RAP. Now, unless I can find a relay that will boost that voltage looks like I'm going to loose RAP. Anyone know of a relay that will do this? If you are handy you could build a curcuit with a high gain transistor that triggers the relay, you will need to know how low the voltage falls to design the circuit without false triggering. The 'ol trusty TIP101/102 dual darlingtons do this well, just make sure they are saturated at the lowest turn on voltage, you may have to add a small signal transistor in front if the beta of the darlington is not high enough. 2N2222 is a decent choice. Chad |
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#7
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"MartyMcLeod" wrote in message news:1114550319.28ba41bb282ef17c794975dedb803aec@t eranews... I have to ask: why are you using a special remote-lead adapter instead of just finding a +12V source? Is it a leased car or something? MAY I MAKE A BETTER SUGGESTION THAT MAY BE LESS COSTLY AND PAINFUL? Anyway, I used to just do the following to provide a turn on lead from a factory radio: 1. Remove factory radio and test for ACC (radio switched wire, 12V) and attach a remote wire, OR 2. Remove factory radio and test for power antenna wire and attach there OR 3. Find the switched wire at the power antenna and run to the amp OR 4. Just run a remote lead to the fusebox. If you want to be sloppy/lazy, you can just put the bare end of the (small gauge) wire around one of the 12V switched (radio, etc.) fuse legs and push it back in. OR 5. Get desperate for a +12V ignition wi search under the dash and start testing connector wires until you find 12V that goes off with the key. Oh, and use a voltmeter, not a test light! Guaranteed to be successful eventually, even in big rigs or boats (yes I have done it in both) Good luck.... Marty Without knowing what the radio does with it's outputs when powered down could prove surprising if the radio is shut off without the car off. IE if it floats up there could be oscillation, or nasty thumps on power up/down. Chad |
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#8
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"MartyMcLeod" wrote in message news:1114612102.749ddf0fa717e844ebe7f1d7e3f0f9a3@t eranews... That's why I put in #3,4, & 5. Always works, as there is always some type of +12V switched wire in a 12V vehicle. It's only a matter of finding one and connecting the remote wire. But if it's still possible to turn off the radio without turning off the key bad things could happen although unlikely. Worst one I saw was one that the remote turn on broke and the person did this. The outputs had no muting FETs allowing them to float whenever the radio was off and he passed a semi with a big power splatterbox linear amp on the CB. Needless to say that person got quite a suprise and a nice reason to upgrade tweets as the RF interference immediately destroyed them. Chad |
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#9
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Yes, it's pretty easy to find out which leg of the fuse to use. Pull the fuse out and turn the switch/ignition on and check for the one with voltage with your test meter. Then use that leg. *DISCLAIMER SO I DON'T GET FLAMED* Don't get me wrong, I would prefer that you locate/use a wire under the dash and make a permanent connection somewere in a more professional manner, but when you're in fix....well we all no how that is. Best of luck to you.!  -- MartyMcLeod ------------------------------------------------------------------------ MartyMcLeod's Profile: http://www.caraudioforum.com/vbb3/me...p?userid=34271 View this thread: http://www.caraudioforum.com/vbb3/sh...d.php?t=216358 CarAudioForum.com - Usenet Gateway w/over one million posts online! |
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#10
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Whoops! That should read "use the opposite of that leg." That way it feeds from the protection of the fuse you're using. Sorry! -- MartyMcLeod ------------------------------------------------------------------------ MartyMcLeod's Profile: http://www.caraudioforum.com/vbb3/me...p?userid=34271 View this thread: http://www.caraudioforum.com/vbb3/sh...d.php?t=216358 CarAudioForum.com - Usenet Gateway w/over one million posts online! |
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