Is this applicable/correct - Automatic 3.5mm Jack Input Switch
09-09-2010, 11:32 AM
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Is this applicable/correct - Automatic 3.5mm Jack Input Switch My buddy just got a new XM radio receiver for his Subi and is attempting to install it along with an input for his iPod or iPhone.
Setup: On the back of the XM Unit, there is an FM transmitter with a male 3.5mm jack and the satellite uses a 3.5mm female jack. He has already fabricated a panel for the XM unit below the regular radio replacing the 6 disc CD changer. There are no pre-fabricated audio input adapters for iPod's or iPhone's for his factory Subaru radio.
Background: At first, I designed a simple DPDT on-on switch schematic with dual input, one for the satellite and one for the iPod or iPhone, and a singular output for the FM Transmitter. This would involve a female Aux jack on the panel he fabricated along with the physical switch. There is probably 1.5" clearance all the way around the satellite unit for whatever needs to be externally accessible.
Idea: He had an idea to remove the switch altogether and design something that would automatically switch to the iPod or iPhone when a jack was connected. Essentially what I designed leaves the ground for the satellite input jack always grounded to the output FM Transmitter jack. I am attempting to use the ground from the iPod or iPhone input to trigger the relay. The output of the relay would go to the FM Transmitter Left and Right respectively and the input for the relay would be each satellite and iPod/iPhone Left and Right. The ground from the relay would tie into the ground from the satellite and the FM Transmitter.
I have included a diagram below. Let me know if this would work, if only theoretically. Also, I don't feel like joining an electronics forum for this simple post, so I am hoping that LS1Tech's electronics gurus are going to find this and be able to help me.
Another thought, would the ground being split when the iPod/iPhone is connected cause interference or grounding issues? If so, couldn't I add a SPST relay with the signal side between the iPod and the DPDT relay and the switch side between the satellite and the FM Transmitter ground. Also tie in the signal side of the DPDT relay to the FM Transmitter, similar to what is below.
Setup: On the back of the XM Unit, there is an FM transmitter with a male 3.5mm jack and the satellite uses a 3.5mm female jack. He has already fabricated a panel for the XM unit below the regular radio replacing the 6 disc CD changer. There are no pre-fabricated audio input adapters for iPod's or iPhone's for his factory Subaru radio.
Background: At first, I designed a simple DPDT on-on switch schematic with dual input, one for the satellite and one for the iPod or iPhone, and a singular output for the FM Transmitter. This would involve a female Aux jack on the panel he fabricated along with the physical switch. There is probably 1.5" clearance all the way around the satellite unit for whatever needs to be externally accessible.
Idea: He had an idea to remove the switch altogether and design something that would automatically switch to the iPod or iPhone when a jack was connected. Essentially what I designed leaves the ground for the satellite input jack always grounded to the output FM Transmitter jack. I am attempting to use the ground from the iPod or iPhone input to trigger the relay. The output of the relay would go to the FM Transmitter Left and Right respectively and the input for the relay would be each satellite and iPod/iPhone Left and Right. The ground from the relay would tie into the ground from the satellite and the FM Transmitter.
I have included a diagram below. Let me know if this would work, if only theoretically. Also, I don't feel like joining an electronics forum for this simple post, so I am hoping that LS1Tech's electronics gurus are going to find this and be able to help me.
Another thought, would the ground being split when the iPod/iPhone is connected cause interference or grounding issues? If so, couldn't I add a SPST relay with the signal side between the iPod and the DPDT relay and the switch side between the satellite and the FM Transmitter ground. Also tie in the signal side of the DPDT relay to the FM Transmitter, similar to what is below.
