Asked — Edited

Do We Have Sound Controlled Leds Yet

I forgot, but , didn't we have the ability to allow the audio to flash LED's like on the robot B-9 chest or the Knight Rider kit? I forget.


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I did something on my Mini-B project that does that. Using a 1watt amplifier tied into the sound board.

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Sound servo will change the brightness of a lamp connected to it depending on the PC sound, I was using it for my hearoids mouth at one point to flicker with voice synth.

I guess you could use it to trigger a Larson scanner (knight rider light) with it.


If you want to power something too big for the EZ-B,

   this (Link)

is what I bought for my B9 chest light. I did not go with the real neon. I used two amber truck LEDs
along with half a dozen little red side marker lights. They are all behind acrylic tubing to simulate neon.
I am getting off track here, but the point is that I have a lot of light running off of the MK114 and it works fine. It was cheap to buy and easy to put together.

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No, I want it to synchronize the voice spoken with the chest LED's. not, like KIT. I meant just to be able to do it with inputing an audio signal into one of the ports of the EZB and then having the port blink the audio to an LED. I said KIT, but I meant voice synch. sorry. I know I can do it with hardware, but I am a little low of cash right now.

Thanks everyone for their comments.


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Try sound servo under servos in the add controls. It adjusts the PWM so will increase the brightness of the lamp/LED according to the sound. No extra hardware required. Give it a whirl and see if it does what you want it to do. It looked pretty good in my robots mouth before I replaced it for the Larson scanner and brain.


Thank You, Rich. That is what I was looking for.


someone just posted something where he wired leds in parallel to the speaker with a resistor, seemed to work well, although the sound servo sounds easier. i guess it would save you a port though


I use a 3 of these to give sound to light ,as my sound is generated from the mp3 trigger card its possible to vary the level using preset resistor on card

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You could use servo sound then connect your digital pin to a switching transistor. It should light and dim with sound. Because the servo signal is a pwm ( pulse width modulation) just in case you don't want to do a scanning set or LEDs or a VU meter.


I like the idea of using the sound servo setup to flash my lights when the robot speaks, but I don't want to use the microphone. I was wondering how I could hook up the speaker leads so the lights would only flash when the robot talks.

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Yes, connecting LEDs to speakers works but the voltage rating of the LED would need to be taken in to account. I think it's this topic it was mentioned in but may have been another where that was suggested and someone confirmed it works.


Lol I answered my own question 2 months ago , that's priceless


@mel using pwm for a servo works kinda good,but if you want level control controlled lights that move like a mouth,you need VU meter and you don't need to buy it as a kit.


@Mel and robot maker - the problem with the VU meter integrated circuits is they put out 2 volts for LEDs which is only enough to directly power green. I believe this is another job for a switching transistor.

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Or a mosfet ;)

What about using another microcontroller which enables output pins depending on the input voltage, connect the input up to a digital port, use a script to get the sound level and PWM to the digital port, microcontroller then enables whichever LEDs need to be illuminated based on the PWM value... Just a thought, no idea what would be needed but I'd be surprised if there wasn't an ATTiny based DIY project for something like that.


JOSH you read the specs on VU meter it says you can set the voltage,vu meter measures volume of audio and apply to leds ,more the sound pressure more the leds turns on like a persons mouth.

PWM is just mostly a flasher that does only one led per pwm output,witch for eyes it works well. MOSFET works better then a transistor because is variable resistor depending on the voltage apply.