Hi, I'm new here. I posted this in a couple of car forums, but I didn't get any real answers. I kind of stumbled onto this forum, and you guys really know your stuff, so here it goes: I need to replace a SPDT relay with something that is silent. here's the background: I have a Streetglow Music Interface and a lot of blue and turquoise neons. The Music Interface has an on/off switch and a music/light switch. When the switch is on "light," all the lights are on, constantly. When switched to "music," it gives off a constant positive(+) signal to the neons and the negative(-) signal switches on and off...on when there's a beat, and off when it's silent. If you add a SPDT relay to the negative output of the MI, you can have the neons flash alternately. The problem is that the relay clicks loudly. Not only that, it clicks once or twice a second. "Thinkster" from the12volt.com drew this out for another member with the same idea. The problem is that it has 12v+ outputs. I need 12v-. I've been trying to email him for months but he's never gotten back to me. I plan on using another switch to choose between having both the blue and turquoise neons on at the same time, or having them flash alternately. I want to still be able to control the neons normally from the music interface. Here's what I want to do... I changed the way the relay is set up... When the MI is set to flash to the music, and the blue neons flash, the turquoise one should not. And vice versa. Can somebody help me come up with a way to replace the relay?
You've confused me here, are there two different wires/connection points for the two levels? The "negative" signal you've shown on the top image looks like it comes from an open-collector transistor switch, active-low, so it allows current through the relay coil to ground when it gets a beat. If it can carry 12V relay coil currents, lots of ways to switch any amount of lighting on. Dead safe way (no risk to the MI) would be to swap the relay coil for an opto-isolator, with a current-limit resistor depending on the opto on the input side, and a current-boost transistor switch on the output to suit your lighting power. Alternatively, a solid-state relay would fit in the same spot and be a more expensive but simpler solution. Both above are only like SPST, so needs a bit more adding for SPDT.
I am not sure what the circuit exactly does, but if a mechanical relay is too loud a solid state relay should do, like http://www.clare.com/home/pdfs.nsf/www/LCA710_R04_3.pdf/$file/LCA710_R04_3.pdf. If that doesn't do because of current or voltage rating browse at the mfg's website for other models. You can implement multi contact relays by paralleling several units. Make sure you don't use a type with SCR or TRIAC output. Those don't turn off under DC load.
well, i've been looking for a solid-state SPDT relay for a couple of weeks now (didn't even know they existed before). i finally tracked down a suplier that would sell without a minimum purchase, but the relay turned out to be USD $300! so, can anyone help me build a circuit that will replace a mechanical SPDT relay? It has to be able to handle about 6-10 amps of power. thanks
Does anybody know how to make 2 (or 3) SPST solid-state relays work like a SPDT? I'll settle for that.
Commercial SS-SPDT have a built-in flipflop circuit so they switch just one of a pair of SPST relays in the same package. Not hard to add.
if its just 12v, consider National's automotive series: http://www.national.com/pf/LM/LMD18400.html http://www.national.com/pf/DS/DS3658.html ect... made for cars, and <$2
