I am very new to electronics in general, but have a specific question around a project I have been imagining.
I’m wondering if it is possible to solder/attach a buzzer to an individual light on an led strip (one of the strips with addressable lights, or one of the chain-able leds sold individually). I want to attach the buzzer in such a way that it will make sound (any kind of sound!) when the light is on, and not when off.
What I’m interested in creating is essentially a “buzzer strip”, using whatever sound gets made by controlling the light.
As I mentioned, my experience with electronics is extremely minimal, so apologies if the question is lacking basic understanding!
Each LED in an addressable strip is, in fact, 3 LEDs, sometimes 4, along with a chip to control them depending on what commands are sent
So, attaching a buzzer to the strip will do nothing without the equivalent control circuitry. There is, however, no reason why you cannot make a buzzer sound based on which LED or LEDs are lit by connecting the buzzer to an Arduino pin and programming it yourself depending on the colour being displayed
If hundreds or thousands of output signals are needed, then it is possible to use the chips from a ledstrips without the leds.
Most buzzers are piezo buzzers that require a frequency to make noise. https://www.adafruit.com/product/160
If you want to use those, then you need chips that have a PWM output in the audible range.
If you can get a WS2801 ledstrip, then you can try to add a buzzer parallel to a led and see what happens. The WS2801 has a PWM output of 2.5kHz. That will work with a piezo buzzer. https://www.sparkfun.com/products/retired/10312
Can you give us a broader view of your projects ?
What is it for ? This is not a beginners project.
The answer to your question is an interesting thread.
A single led drops a few volts when lit. If it is meant to shine with full effect, it receives a steady voltage. A piezo parallel to the led will receive same voltage. If it's a passive piezo element, it will be quiet. If the led is supposed to shine with half effect, it receives a sawtooth signal with some frequency. That will make the piezo sound, unless the piezo swallows too much current it will put the feeding circuit out. And with a very low light effect the square wave will probably fade the sound in the piezo.
If it is an active buzzer, it keeps noise with its own internal frequency when fed with a steady voltage (full light on led). But again, it might draw too much current. And with half light the sound might get weird. There's the frequency of the active buzzer and the frequency of the PWM controlling the light level. Definitely an undefined situation and not how active buzzers should be used.
What I want to do is create an controllable array of buzzers, the audio equivalent of an led strip. Armed with a strip of N speakers/buzzers, my interest is in placing the strip on a wall (say surrounding you in a room) and then create sound in patterns I define from software around a listener (I don’t really care about the leds). If the light is on, it makes sound, if off it does not. I wouldn’t need a buzzer/speaker per led, more like every 4 or 5 maybe (so they are perhaps 5 or 6 inches apart). The goal is an audio installation I could set up and leave running.
Another person above mentioned “this is not a beginner project”, which I suspected as I was looking into doing this. My question about being able to simply piggy back off of an led strip was wishfully thinking I could solder a buzzer per led and get some sound.
I was thinking that the current draw might create problems, especially since I want to connect many speakers along a strip. If it is a problem, maybe there is a way to boost the current between the led->speaker connection? I was hoping the various colors/intensity would result in interesting waveform changes, it sounds like a passive piezo would do what I want.
I really appreciate all the answers! I may not pursue this idea at all but it’s very helpful to get a sense of how much of an investment the idea is in terms of how much learning I need to do, and how much work it would be to achieve.
If the buzzers would have an annoying frequency, then there is nothing you can do about it. I feel sorry for the listeners.
I think you are getting into a lot of trouble for no reason if you use a ledstrip.
I prefer a sine wave and speakers.
There are very cheap Class-D amplifiers with a "Enable" pin. The PAM8403 modules cost a dollar and it has a Mute and Shutdown pin.
The Arduino could have extra hardware for more output pins, to control all the Mute or Shutdown pins.
Potentially hundreds, which is why I’m trying to cut down on the amount of wiring needed and focus on software control. Led strips assume you want a lot of them and come with ways to control the lights from software. It would of course be great if it were reasonable to create a large/high numbered strip of speakers intended for the purpose.
As for annoyance, I’d imagine it would come down to how loud it is and how it’s used. I know the frequency range is quite high so not a lot of volume is needed.
I would continue researches, leaving the idea of using LED strip microprocessors, which I believe can be purchased as a bare components, def on the table.
If you think from another perspective, what is the final sound experience you want to achieve? Great sound experiences are achieved with two speakers. I'm talking about music. In a big hall you might have two speakers. They produce a stereophonic sound, which at its best will give a sense of a continuous "screen" of individual sound sources - the individual instrumetns in a symphony orchestra. You can increase sound channels from 2 to 4 or 5 or 8, whatever, by adding speakers. But hundreds is overkill. If it would give anything to the listener, it would be used. That said, I think there are experiments, where tiny speakers have been used and placed all over the hall, to create something peculiar.
A single Arduino will have a hard time producing different waveforms att different frequencies. The led strip only receives - or produces - square wave like patterns. And each has the very same frequency. A led/servo board like the PCA9685 can handle 16 servos or leds and you can daisychain them to as many piezos you want. But if I remember correctly, all 16 piezos connected to one PCA9685 would have the same frequency. Each individual piezo however could still have its own dutycycle. Changing dutycycle would change the sound slightly.
Great, thanks for your input. Will try out piezo + strip, as that sounds like it might work for my purposes. Will start with just a few and if I happen to get anywhere will post here with progress. Will be fun to sequence led lights in any case.
Thanks again all for feedback/input. I personally think there are some compelling non-art cases for even very limited capability speaker strips (directional indicators for vision impaired), maybe one day they will be a real thing.
I am working on a Halloween prop that will control dozens of servo motors. I bought a tube of WS2811 chips intending to use the pwm output of the chips to drive the servos.
I dropped that plan in favor of simply using an ESP8266-01 at each servo then controlling them with MQTT. This would provide a lot more flexibility for placement. (The prop will be a field of skulls that respond to movement by turning toward whichever PIR detector last "saw" movement.)
It is still a work in progress.... But, I can see the same arrangement with a small audio amplifier chip and speaker instead of a servo. The ESP could generate a tone (using the appropriately named tone() function) based on instructions from the controller over MQTT.
Or if you don't care about the frequency, the ESP could drive a piezo device directly.
and if I happen to get anywhere will post here with progress. Will be fun to sequence led lights in any case.