Recreating an audible water beacon

I've been tasked with recreating a device that outputs selectable tones via two loud speakers (home alarm siren type). The device will be enclosed in a box and attached to a floating buoy. When turned out it will simply emit a tone consistently. The original design used a 12V battery that could be recharged. Also the original design used what appears to be NE555 Timer chips. Are these used to generate the pulses?

While in my head the concept seems simple, I am concerned with a few items. #1 - How should I power the speakers? Surely an Arduino with a 9V battery will be insufficient? #2 - how to set tones? Using a toggle switch? #3 - is Arduino a good solution for this?

See images of the existing circuity and PCB. Any guidance here is appreciated.

Appears to be a simple enough design that you could draw the connections between components to recreate the schematic and go from there.

Why Arduino? If all you are doing is to make a tone sound, then the 555 is probably the best chip.

I was hoping that using the Arduino would be a better solution by expanding the tone/sound options.

What sort of tone/sound options are of interest? The 555 chip can output any audio frequency.

With Arduino you need an amplifier to drive the speaker.

jremington:
What sort of tone/sound options are of interest? The 555 chip can output any audio frequency.

With Arduino you need an amplifier to drive the speaker.

We would like a variable range of tones and pulses. Needs to be loud. So yes, I need an amplifier. That's where I am stuck. Is an LM386 sufficient? The loud speakers are 15W 8 ohm.

Is an LM386 sufficient?

You tell us. The LM386 maximum output power is less than 1 Watt.

jremington:
You tell us.

Helpful.
Is there an amp you recommend?

To be honest, I think Arduino is overkill in this case. I think you just need someone to recreate the circuit as it is… might be worth asking in a general electronics forum (All About Circuits comes to mind).

With a few more pictures and a description of what wires go where, I could actually take a stab at developing the schematic and BOM. I’m guessing most of the parts could be ordered from Digi-Key but you’d still need to have a custom PC board made.

Hi,

Can you please tell us your electronics, programming, arduino, hardware experience?

Why can't you reverse engineer the old unit?
Then make another unit?

Tom.... :slight_smile:

I'd place my electronics and Arduino knowledge between novice and intermediate. I agree that the Arduino might be overkill. I was hoping to add some more to the original design however. Maybe LED status or an LCD screen with information on it and 3D print a case to contain all of the components. But wanted to get the audio working first.

I have it working with the piezo speaker and two trim pots to adjust the tone frequency and delay but need more power to drive the speakers.

Would it be feasible to use a 12v DC source to power the Arduino (nano) and the same source and a transistor to amplify the signal to the speaker?