How to create a Christmas Light Show?

Hello, I am trying to create a circuit that involves 2 LEDs, an Op-Amp 27, transistor 2N30904, Arduino uno, and the microphone from the analog parts kit. I know that I need some resistors to connect to the LEDs, but I am unsure as to what resistance and capacitors for the filters. The goal of the circuit is to have a high pass filter and low pass filter connected from the microphone which then triggers a certain LED to glow. I am unsure about how to create the HPF and LPF. Are they able to be connected from the same ground and 5V? And no coding should be involved. Any advice would be greatly appreciated!!!!

The language that we use to describe circuits is the schematic.
How to make a schematic you can post.

Actually Google is the best place to find this.

Start with a block diagram of what you think is needed.

Flesh out the blocks with a schematic.

Come back and show us what you end up with, we can add comments.

Here is a brief schematic of the circuit I was hoping to achieve. Mainly I am unsure of how to construct the HPF and LPF with only my small arduous uno.

Here might be a start.


Make a low and high pass filter.

Feed these to 2 transistor/opamp circuits then to two analog inputs on the Arduino.

I have added the mic, op amp, transistors, resistors and LEDs. Not sure if they are in the right spots. I watched the video and know to use the RC for LPF and HPF. In the schematic it comes branching off of the op amp which I am unsure about.

Have a google of op amp circuits , you will need to amplify the signal from the microphone upto a suitable level for the Arduino analog input ; 5v.

Really it’s worth playing with some basic op amp circuits first with the aid of a cheap multi meter to get started .
Some basic circuit knowledge is useful


And maybe

What video? What schematic?

The khan academy video suggested from a former comment

I guess my question now is can I put my HPF and LPF through the same op-amp or would I need to use two op-amps for each. Remember the goal is to have the frequencies of a song filter through and a higher frequency would lead to 1 LED to light while a lower frequency would lead for the other LED to light.

Two OpAmps.

What OpAmp part number do you have ?

I have the Op amp 27

This is the microphone that I would be using as the sound sensor

I don't see it. Can you please post it?

That one probably won't work well on 5V.

Do you have single supply op-amps ?

I am sorry I am unsure about this. The project is for school so I am not an expert with all this terminology. I have the analog parts kit from analog devices. Analog Parts Kit by Analog Devices: Companion Parts Kit for the Analog Discovery - Digilent

See your AD8542.


A state variable filter might be useful for you because it has simultaneous low pass, band pass, and high pass outputs.

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