Pedal nerds: Flashing LEDs responding to transients.

James · Post by **James** » Thu Feb 10, 2011 8:39 pm

How difficult is it to make a little circuit that makes an LED flash when a signal reaches a certain level? Sort of like a peak meter I guess. I'm guessing you'd need something in the circuit to control a threshold above which they turn on, and you would need to tweak the circuit to get that right, and then maybe something for a decay after they turn on, but I've no idea of the mechanics of it all.

Will · Post by **Will** » Thu Feb 10, 2011 9:01 pm

Flashing? Like a warning light? Or just something that lights up when signal goes through?

A circuit to boost the hell out of the signal, followed by an led placed between the signal and ground. Then a knob to control the amount of signal going to the LED (threshold, basically). That would be the simplest thing.

paul_ · Post by **paul_** » Fri Feb 11, 2011 4:53 am

Some EHX pedals like the polychorus have an overload LED.

Haze · Post by **Haze** » Fri Feb 11, 2011 4:58 am

luckily i've had this kicking about

Will · Post by **Will** » Fri Feb 11, 2011 5:24 am

I'd still throw in at least a trimpot before those LEDs to set the sensitivity.

endsjustifymeans · Post by **endsjustifymeans** » Fri Feb 11, 2011 4:25 pm

James wrote:How difficult is it to make a little circuit that makes an LED flash when a signal reaches a certain level? Sort of like a peak meter I guess. I'm guessing you'd need something in the circuit to control a threshold above which they turn on, and you would need to tweak the circuit to get that right, and then maybe something for a decay after they turn on, but I've no idea of the mechanics of it all.

The wolfs eye on my Grumbly Wolf does this, perhaps timhulio can offer something up.

Post by **Mike** » Fri Feb 11, 2011 4:33 pm

Tim is using it for clipping.

James doesn't want that, since it will degrade the signal.

He'll want something like the circuit Haze implemented but most likely connected after a signal splitter so his pass through signal isn't mangled.

James · Post by **James** » Fri Feb 11, 2011 7:14 pm

Yeah definitely no clipping. I want it as independent from the signal as possible.

So if I split the signal (don't know how to do that to keep it seperate) I can just use that simple circuit and adjust the value of the cap to get the sensitivity right?

I want to use two LEDs so do I just use a resistor in front of the first one and connect the second in series?

timhulio · Post by **timhulio** » Fri Feb 11, 2011 7:45 pm

The answer might be 1. buffer/splitter like Mike said. Then 2. something to do with zener diodes to set the cut-off voltages for each LED.

Just skimming, but the circuit Haze posted looks like an all-or-nothing deal. The sexiest thing would be the LEDs lighting incrementally.

Sorta like on this lovely pedal I'ma gonna get as soon as it's out:

light rail coyote · Post by **light rail coyote** » Fri Feb 11, 2011 9:17 pm

timhulio wrote:The answer might be 1. buffer/splitter like Mike said. Then 2. something to do with zener diodes to set the cut-off voltages for each LED.

Just skimming, but the circuit Haze posted looks like an all-or-nothing deal. The sexiest thing would be the LEDs lighting incrementally.

Sorta like on this lovely pedal I'ma gonna get as soon as it's out:

WOW, that thing looks amazing. It has controls like a real compressor. I would love to dink around with one of those.

timhulio · Post by **timhulio** » Fri Feb 11, 2011 9:47 pm

Supposedly a UREI 1176 compressor in pedal form. I'm quite excited about this. And it's good for guitar too.

Pedal nerds: Flashing LEDs responding to transients.

Pedal nerds: Flashing LEDs responding to transients.

Re: Pedal nerds: Flashing LEDs responding to transients.