On/Off button + Toggle wiring question

No_6 · Post by **No_6** » Mon Feb 06, 2012 9:30 pm

Hey all. I was wondering if it was possible to wire something up with simple switches purchased from RadioS---k that will do this:

1 Latching pushbutton on/off
1 Toggle that will switch between a sound activated circuit and a bypass that will supply steady power.

Also, the thing is wired up so that all the LEDs are in series of 4. There are like 16 of these that all are connected to a single deans connector. Now if the above works, how do I calculate the resistor I would need to convert the 12vDC to about 10vDC when I have it switched to the bypass "steady on."

Thanks!

en'til Zog · Post by **en'til Zog** » Mon Feb 06, 2012 9:56 pm

Most suppliers sell "push-ON push-OFF" button switches. NOT "momentary" types.

For the toggle switch, try a "double pole double throw center OFF switch" or "DPDT center OFF" type.

If you don't need the switch to cut power in the middle position leave off the "OFF" part.

No_6 · Post by **No_6** » Tue Feb 07, 2012 12:22 am

I have a SPDT switch. So that won't work?

en'til Zog · Post by **en'til Zog** » Tue Feb 07, 2012 8:01 pm

SPDT switches should work well. I just like a DPDT switch so I can switch POSITIVE and NEGATIVE at the same time. They give me more options if I change my ideas.

They also make good reversing switches.

Stocking the DPDT keeps down the number of bits I have to keep around.

Good luck!

No_6 · Post by **No_6** » Wed Feb 08, 2012 10:09 pm

Thanks Zog! It all worked out. I wound up getting a 10k Ohm volume switch for the second circuit which allows me to dial it down from 12vDC to about 9ish, really the perfect solution. Now to wire up the TIP31C to the stereo jack to see if I can get that to work...

Sparky · Post by **Sparky** » Wed Feb 08, 2012 11:27 pm

just remember that if you have multiple series of 4 leds in parallel and one resistor dropping voltage, the current through the resistor is the current through 1 series of LEDs * the number of 4 LED series loops. So typical new LEDs would be 4loops * 0.020 Asmps per loop = 0.080 Amps total.

Wattage of the resistor is Amps * Volts (the voltage dropped so 12- 9 is the volts the resistor is handling). So 0.24 watts. a 1/4 watt resistor will do in this case.

BTW how did you come up with 10K ohms? Just wondering.

No_6 · Post by **No_6** » Thu Feb 09, 2012 2:43 am

Sparky wrote:just remember that if you have multiple series of 4 leds in parallel and one resistor dropping voltage, the current through the resistor is the current through 1 series of LEDs * the number of 4 LED series loops. So typical new LEDs would be 4loops * 0.020 Asmps per loop = 0.080 Amps total.

Wattage of the resistor is Amps * Volts (the voltage dropped so 12- 9 is the volts the resistor is handling). So 0.24 watts. a 1/4 watt resistor will do in this case.

BTW how did you come up with 10K ohms? Just wondering.

It was about the right size. Heh. Tested everything and it works well enough. It won't turn the lights all the way off, but it definitely gets it low enough to get exactly the effect I want. So I took a blind shot and it paid off.

Sparky · Post by **Sparky** » Thu Feb 09, 2012 11:45 am

my calculation was 37.5 ohms, a 10k certainty is providing enough voltage drop to protect the LEDs.