Can an Arduino Uno be used to make the tone in the link?

Projects General Guidance
1

Thinking of using LM386 module with an external power supply and a 8 ohm, 0.5 W speaker.

(HOSPITAL HEART MONITOR | Soundsnap)

  1. Will I need extra storage element to store the tone which will be maximum 3 seconds long ?
  2. Will the sound be as good quality as heard in the above link ?
  3. How loud in dB will the sound be 1mt away from the speaker when on full volume ?
2

The loudness of a beeper or speaker depends on lot of the case that it is in and how the speaker is mounted in the case.

Example:

void setup() {}

void loop() 
{
  tone( 6, 1000, 180);
  delay( 900);
}

Listen to the example in the simulation:

3

  1. Are you just amplifying an output generated by tone()? Then no extra storage.

  2. Yes, unless you use a ridiculously cheap speaker

  3. About 87 dB

HTH

a7

4

If you could provide some reference that would be great!

5

Wokwi is a good Arduino simulation tool I wasn't aware of. Thanks!

6

google

 0.5 watt 1 meter sound level

I found

90 dB is one watt at one meter, -3 dB is halving that, so.

a7

7

Yes, gotta love wokwi, even if on an iPad there is no… sound from tone(). :frowning:

a7

8

Half power will result in -3dB sound level, that is acceptable.

But the writer of the article assumes that the speaker sensitivity is 90 dB @ 1W/1m, and no where describes the speaker as "the circular one, 8 ohms input resistance, found commonly in cheap electronics".

Can we still use the 90 dB value for our calculations ?

10

I think you will have to put the items together (tone source, amplifier and speaker) and get empirical.

I think with an efficient speaker, you'll get quite a bit of sound. On the other hand, amplifiers with more power are available, in small modular form, and are relatively inepensive.

I think the speaker itself will be the key component.

What is the desired goal for purpose for the sound?

a7

11

Would like to achieve ~88 dB at 1 Mtr. since that is the rating of one of the alternate devices being used in our target environment

Would appreciate if you could mention few modules/ IC numbers.

12

Do you need a constant tone or a varying one?

If you need a constant tone you could use a modified 12v buzzer and a relay with a delay or millis

13

Controlling the buzzer - - Arduino modular electronics project - Circuitar.

14

I used a LM386 module . Powered it with a bench top power supply (5V) but whatever pot setting on the module I choose, there isn't any current draw greater than 20 mA. The 8 ohm, 0.5W speaker just isn't loud enough. It should draw 250 mA to consume 0.5W and the power supply is capable of providing 30W.
I am using Android based Sound meter app to check sound levels. If I hold my phone very close to the speaker the reading is around 60 dB. I also have a louder speaker in a product, whose sound levels I want to match and it gives a reading of around 80 dB.

What could be the reason, the speaker in my setup isn't consuming 250 mA and isn't loud enough ?

15

Beyond the LM380 and LM384 chips, which I have used and of course the LM386 since forever, I'd just be googling. Which I leave in your good hands. :expressionless:

^^ Looks like I fell asleep before hitting reply…

Now the LM386 can drive 4 ohms, so maybe try one (or two 8 ohm speakers in parallel), and it can take 12 volts (variants can take more) power supply, so perhaps providing that voltage to,power the amplifier will get you closer.

a7

16

also remember a speaker will sound much louder when you put it in enclosure

17

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