So, to sum up, I will need:
-A construction box to house my project
-6 female 3.5mm audio ports
-3 line-in cables
-3 DPTD relays
-Some way to draw power from USB (I cut an extension cord for this purpose)
-A switch
-Lots of wires
By the way, should I go with a solid state relay? Is there anything more I need to ask for the relay at the store (example: voltage), or asking for "3 DPTD relays" is enough?
Thanks
EDIT: I was reading this:
quote:
Originally posted by http://www.geofex.com/Article_Folders/relays/relays_for_switching_audio_signa.htm
There are some other things you need to know. Those coils in the electromagnets - they act like (and are!) inductors. When you set up current in them to make the relay switch positions, you are loading up an inductor with current. When you try to turn it off, the inductor responds by reversing its voltage to try to keep the current flowing. This happens as fast as you can cut the current off, so inductors can make very fast, sharp voltage spikes. Since inductance varies as the square of the number of turns on a coil, it usually happens that many turns of very thin wire on a higher-voltage (and hence, lower current) version of a relay will have much larger inductance than the same-physical-size relay in a lower voltage (hence, fewer turns of larger copper wire) version. The coil inductance directly slows down the build up and ramp down of current in the coil when you apply a voltage, so in general, higher voltage relays take longer to operate.
The fast, sharp voltage spike that comes from the relay coil reversing its voltage to try to keep the current flowing can kill your driver transistor. You have to protect the device from the voltage spike. This is usually done by placing a diode in parallel with the relay coil, but in a direction where the diode does not conduct when the relay coil is turned on. The diode only conducts when the relay coil reverses the voltage across it at turn-off. This clamps the voltage spike to only one diode drop more than the power supply voltage.
Should I worry?
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