The search for "gentle" warning sounders - RESOLVED

[SteveThackery]

I'm converting a vintage car to use flashing indicators. I would like there to be an audible warning, just like a modern car. Perhaps a gentle bong.... bong.... bong...., or maybe a soft click.... click.... click..... I want it to be a pleasant sound - not harsh or loud.

I've been looking for a suitable sounder, and a quick circuit around Amazon and some other suppliers has come up with nothing suitable. There are plenty of piezo-sounders, but they are designed as alarms, having an ear-piercing tone. And then there are various electronic buzzers, which from experience have a rather harsh tone.

Can anyone recommend something suitable? They must exist somewhere, because they are fitted to all modern cars, but I can't find them anywhere. I'd be happy to build such a sounder given a circuit diagram.

All suggestions and ideas are warmly welcomed. Thanks.

[booscrawl]

Use a 555 and a relay or solenoid? The clicking in older cars used to just be the literal headlight relays clicking on or off with a small hot-wire oscillator switch driving the relay. Modern cars imitate that by playing a gentle clicking sound over the audio system.

Ebay has things like a "5-Step Adjustable LED Sequential Retrofit Flash Module Car Turn Signal Light Kit" or "12V Chrome Universal For GM Ford With Flasher Street Hot Rod Turn Signal Switch".

[aeg]

Flasher, from your local auto parts store... It's a relay with the circuit built in, or a bimetallic mechanical oscillator, depending on the car. It gives you both the click and the blink.

[Analog Kid]

Flasher, from your local auto parts store... It's a relay with the circuit built in, or a bimetallic mechanical oscillator, depending on the car. It gives you both the click and the blink.

+1.

Keep it mechanical, man. No need to impose anything digital on the car.

[SteveThackery]

Thanks, guys.

For complicated reasons to do with the trafficators (the yellow arms which swing out from the B pillar - these were used before flashing indicators were invented), it needs two flasher relays, one for each side. If I want to move them inside the car I'll need to extend four of the wires in the wiring loom under the bonnet through to the car interior. I can do this, but it feels a bit inelegant.

The existing wiring loom will reach if I fit the relays under the bonnet. I was planning to take just two new wires from the relays through to the interior and install a sounder under the dashboard - hence my question.

I guess it would be simple enough to extend the wiring loom and install the relays under the dashboard, and just use whatever sound they happen to make as the warning sound. I just thought it would be nice to be able to choose the actual sound. Especially if the relay clicks are a bit faint.

[themadhippy]

positive from the left and right lamps  to the ac in on a bridge rectifier,output of the bridge rectifier to power the  loudest 12v relay you can find

[Benta]

The blinker click sound has been done by a sound relay or speaker for the last 20 years.
I suggest you visit a wrecking yard and rip out what you need.

[Someone]

positive from the left and right lamps  to the ac in on a bridge rectifier,output of the bridge rectifier to power the  loudest 12v relay you can find

positive from the left and right lamps  to the ac in on a bridge rectifier, output of the bridge rectifier to power the loudest 12v most convenient automotive indicator relay you can find

As posters above keep saying. This is an off the shelf part with no need to re-engineer all the details. Where you'll fall over is the tangle of vehicle standards which require the audible and operating tell tale to change if the indicator lamps are not functioning.

[Psi]

Sparkfun have some boards that will play a wav/mp3 from a sdcard whenever you set an input pin high.
If you route that into a mixer on the car stereo amp you can make your own custom sound and change it as needed until you find something you like.

I cant say i've tested any with really short audio files though, but they will probably be fine playing a sound every 1000ms or so.

[tom66]

The old Peugeot I had used a piezo buzzer.  For the indicator, it seemed that the engineers just drove the piezo on and off with DC, which produced a click on each cycle of the indicator.  Other sounds, like headlights left on, or parking brake on, were implemented by playing tones through the piezo.

I'd imagine the easiest way to solve this problem would be with a microcontroller; receive the inputs (indicator L/R, headlights, engine on, door open) and a few truth tables can be created, like "beep 1 if headlights on but engine not", or "beep 2 if engine on and doors open".

[Psi]

Reminds me of my old Car PC. I mounted a plunger spring solenoid behind the dash console and pointed the plunger at the solid metal frame that the entire plastic dash console was mounted to.
It wasn't for indicator sound though, it was feedback when buttons were pressed.
It gave a really satisfying THUNK when you pressed the buttons on the dash that controlled the car PC functions.   

[Kilrah]

Wire up a relay that clicks on/off even if it's not actually switching anything...

[SteveThackery]

Well, I bought two different types of flasher relay, one of which says it is "electromechanical", but neither makes a clicking sound.



Several of you suggested a relay - simply to make the click - which should be fine. Ditto if I can find something in a breaker's yard. So thank you for those suggestions.

Regarding the requirement to warn of a failed flasher bulb, my Riley (1953) predates that regulation and it was not applied retrospectively, so obviously a warning is definitely desirable, but I would still be legal without.  As it happens, I think the flasher relays do change their rate when a bulb fails, so as long as I can extract some kind of noise from them it should be fine.

A DC 'click' from a piezo sounder is worth trying - it didn’t occur to me, so thanks. Out of interest, the car doesn't have door switches, so no truth tables are required at the moment. 

For now I'm going to find a relay from somewhere, the sole function of which will be to make a click. In the longer term I'm going to have fun hunting down a cool "bonger", or even making my own.

You've been great, guys - thank you for your contributions.

[Roehrenonkel]

Hi Steve,

no, you don't want a bong (even a gentle one) at the wheel.
(https://en.wikipedia.org/wiki/Bong)

What you want is a Boing like:


:-))

[Randy222]

You already have the blinking part?

Just wire in a 30 or 40A car relay, just the coil end of it.
These small relays always make a notable click sound when the coil activates and some sound when it deactivates.

"vintage"? So high side switching? Makes it easy to parallel the coil + to the blinker side, and just closest gnd for other end of coil. Probably need two though, one for each side.

[SteveThackery]

You already have the blinking part?

Just wire in a 30 or 40A car relay, just the coil end of it.
These small relays always make a notable click sound when the coil activates and some sound when it deactivates.

"vintage"? So high side switching? Makes it easy to parallel the coil + to the blinker side, and just closest gnd for other end of coil. Probably need two though, one for each side.

Thanks, @Randy222. Yes, it looks like a relay used as a "clicker" will be a good solution. Something like a relay coil isn't polarity sensitive (or it won't be when I've snipped the flywheel diode) so I can just connect it between the two feeds to the indicator lights. The relay coil current finds its way to earth through the bulbs on the non-flashing side. Not enough current to illuminate the bulbs.

[Randy222]

You already have the blinking part?

Just wire in a 30 or 40A car relay, just the coil end of it.
These small relays always make a notable click sound when the coil activates and some sound when it deactivates.

"vintage"? So high side switching? Makes it easy to parallel the coil + to the blinker side, and just closest gnd for other end of coil. Probably need two though, one for each side.

Thanks, @Randy222. Yes, it looks like a relay used as a "clicker" will be a good solution. Something like a relay coil isn't polarity sensitive (or it won't be when I've snipped the flywheel diode) so I can just connect it between the two feeds to the indicator lights. The relay coil current finds its way to earth through the bulbs on the non-flashing side. Not enough current to illuminate the bulbs.

I would recommend you gnd each coil to chassis or two separate existing gnd wires, and do not tie the coil gnd's together at the same point.
1) You could allow the coil current to flow through the non-lit bulb (one relay solution, the easy way), but this will shorten life of the bulbs (assuming bulbs are filaments). Some relays are directional current to throw the arm.
2) The reason not to tie coil gnd's together (if using the two relay solution) is only because if the gnd lifts up off of gnd (for whatever reason) then the voltage (and amps) on coil 'A' has a back path through coil 'B', which perhaps is not a big deal, but the normal coil amps is now slightly less than halved as it has to flow through A-B-bulb. This is why I don't like "gnd points" on modern vehicles where 3-4-5 wires are under one gnd lug/bolt/screw. Gnd is "gnd" only when gnd is connected, etc.

[SteveThackery]

@Randy222, do you realise that the layout I described was used universally, for decades, in vehicles with only one turn indicator warning light, despite all your theoretical objections? Obviously we're talking about pre-ECU systems, where the indicators are just another I/O port. This is the schematic:



When signalling left (say), 250mA flows through the 3W warning light and then to ground via the two right-side 21W bulbs in parallel. Circa 125mA in each bulb won't shorten it's life, and won't produce even the faintest glow. The bulbs look just like an earth to the warning light, so it lights brightly. The circuit is symmetric, so the same thing happens, but mirrored, when indicating right.

My Riley uses two flasher relays, one for each side, because the trafficators require a continuous voltage. Apart from that the warning light is driven in exactly the same way.



As you can see, as long as I keep the current in the "clicker" low, it will work just fine.

[Benta]

I'd simply use a small speaker with a series cap. That'll give a nice "relay-like" click.

[Randy222]

Probably best to start a thread using the schematic up front.
Did I object, or provide recommendations? Two different things.

And yes, heat cycling the non-used bulbs (125mA) still shortens their lifespan. Being acceptable is on you.

"I'm converting a vintage car to use flashing indicators. I would like there to be an audible warning, just like a modern car."

The modern car aint using your schematics. Why not build the ckt in modern ways?

For all your searching & buying a relays that dont have the sound you need, the simple solution was there all along, you just never saw it? So be it, can probably "close" this thread now.

[SteveThackery]

Probably best to start a thread using the schematic up front.

I considered the schematic to be irrelevant because my quest was for a pleasant-sounding 12V sounder. Nothing about the schematic is relevant to that basic question.

And yes, heat cycling the non-used bulbs (125mA) still shortens their lifespan. Being acceptable is on you.

So the normal lifespan for an incandescent tungsten filament bulb is around 1000 hours. By how much do you think it will be reduced?

The modern car aint using your schematics. Why not build the ckt in modern ways?

Because modern cars have multiple ECUs, CAN busses, LED indicators, etc, etc. So it's not like I can go to a breaker's yard and pull out the flashing indicator circuit from a modern car. Hence my original question: can anyone recommend a pleasant-sounding bonger or clicker.

For all your searching & buying a relays that dont have the sound you need, the simple solution was there all along, you just never saw it? So be it, can probably "close" this thread now.

I do believe you are being petulant! 😄 Can you not cope with being corrected on a technical matter? 😁

My original question is justified: nobody has yet identified a suitable sounder. I do appreciate the following suggestions, though:

a/ use a relay to make a mechanical click sound
b/ use a capacitor and loudspeaker to make a click sound
c/ find a flasher relay that makes a click sound
d/ make a homebrew electronic or microcontroller tone generator

You see? If I want something other than a click, I've got to go homebrew.

This is an off the shelf part with no need to re-engineer all the details.

As should be obvious, nobody has yet identified an off-the-shelf part, unless I settle for a simple clicking sound. What I find fascinating is that there does not seem to be an off-the-shelf sounder or alarm that makes a pleasant, gentle warning tone; they are all buzzers or piezo-"shriekers".

Anyway, I'm going to give up on finding an off-the-shelf sounder for now, and just settle for a basic clicker - probably a relay or the trick with a cap and speaker.

[NiHaoMike]

The piezo buzzer element salvaged from an old smoke detector might work well enough. When driven by a slow square wave, you'll get a pretty pronounced click on every transition.

[Langdon]

The sound comes from the relay that controls the light bulb.

And on older cars the relay switches itself (somehow) without a 555 timer.

Please see: https://en.wikipedia.org/wiki/Relaxation_oscillator

On older cars, if a bulb burns out the turning signal blinks faster because the bulbs are part of the oscillation circuit!

[themadhippy]

heat cycling the non-used bulbs (125mA) still shortens their lifespan

and yet it  was  the done  way for eons,i  think every motorbike i owned was wired that way

a suitable sounder.

and now for something completely different,how abouts a solenoid striking the back of the dash for a thud or a bell dome for a gentle tinkle when flashing

[SteveThackery]

The sound comes from the relay that controls the light bulb.

And on older cars the relay switches itself (somehow) without a 555 timer.

The old flasher relays used a bimetallic strip, which was crimped in such a way as to make it somewhat bistable. The current to the bulbs heated the strip, which would snap open, disconnecting the current. The strip then cooled and snapped closed again. The snapping made an audible click. If the relay was mounted on a metal panel, the click was amplified.

I couldn't find a "clicky" flasher relay when I checked out Amazon, eBay, et al earlier this week. Even one described as "electromechanical" by a local autoelectrical specialist was silent.  It looks like only clicks are easily available: a clicking relay, a clicking loudspeaker, a clicking piezo sounder, a solenoid bashing the back of the dashboard (😄), and so on. If I want a nice "bong" sound, it looks like a homebrew will be necessary.