18-cent Piezo Beeper: Tiny, Loud, and Liberating

erco

erco

Senior Member
At ten pieces for $1.79, these self-contained piezo beepers are a great add to your parts bin: tiny and surprisingly loud. They have a built-in oscillator, just give them 5V and plug your ears. Leave the sticker on for lower volume. http://www.ebay.com/itm/370951312115

Any PicAxe-generated sound halts all program execution until the sound finishes. These beepers liberate your project. They can connect directly to a 5V output pin. Just make it high to turn on the beeper and get back to program execution. Or toggle it, as I did here on my 20M2 board: http://www.youtube.com/watch?v=ICAyUKGNldY
 
premelec

premelec

Senior Member
It appears these units are electromechanical [magnetic] rather than piezo - and up to 25ma - is that the case?
 
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oracacle

Senior Member
i have used similar devices in several projects, all of which were electro machanical, 25ma seems about righ for one that size
 
erco

erco

Senior Member
OK, perhaps electromechanical. Beeper draws just 11 mA when driven directly from a PicAxe running on 5V, and it draws 28 mA when hooked directly to 5V.
 
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Paix

Senior Member
@Erco, Resisting, resisting.

I should buy shares in China Mail I think and take an annual dividend in magic electronic devices! Happy New Year.
 
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Paix

Senior Member
@Erco, Failed. Just needed a couple of small inexpensive sounders, so had to do a search to find your post . . . buying !
 
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srnet

Senior Member
And they are loud enough when driven from a 3V3 powered PICAXE too.

I was replenishing supplies yesterday, 10 of them cost me £1-05 delivered .......
 
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Paix

Senior Member
@TCH, I see that, but with $33 shipping that makes the 200 come in at $1.69 per 10 at the $0.90 bid price.

I have this vision of a not so old Chinese guy with flashing thumbs on his abacus working out the figures on all these deals, confident that sooner or later someone will make a small financial misjudgement that will tip the bottom line balance, and very confident that the mistake won't be his . . . :)

@Srnet, I apparently paid over the odds by £0.08 delivered, Mr Wu, and Paypal, win again!
 
Z

ZOR

Senior Member
Have I missed something? I just followed the link, bought 10 for US $1.79, postage free to UK. Do me nicely thanks. Surprised The Old Fart's not been on this one for his burglar alarm.
 
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Paix

Senior Member
@ZOR, I don't think so, on the page you arrived at, down to the right among the similar offers was the 200 piece item.

You and I paid the same price, but apparently we paid a whopping 8p more than Srnet did.
 
Z

ZOR

Senior Member
Thanks erco, I'm happy, I followed Texasclodhoppers link, as your link does not ship to the UK.

Srnet was replenishing supplies?, must be very noisey in Cardiff now!
 
grim_reaper

grim_reaper

Senior Member
Thanks erco. I was just looking for something to make an annoying noise with. Got the ones just above for 7.3p each!

Bit worried about the description now... the photos obviously show them fitting in a hand, but they text says they're six centimetres in diameter!! That's one giant hand...
 
grim_reaper

grim_reaper

Senior Member
That's what I thought at first... but if you imagine the same hand holding a 5mm LED, the buzzers look nearer 8 or 9 mm?
Maybe they mistranslated 6/10ths of an inch? :rolleyes:
 
Hemi345

Hemi345

Senior Member
Is anyone else having trouble with the first page of this thread? It redirects the browser to YouTube.

erco, have you run these at a higher voltage, say around 9V? I'm looking for something loud, like smoke/fire alarm loud that will be audible from another room or floor in a home. Tossing around ideas for building a water detector and want something loud.
 
JimPerry

JimPerry

Senior Member
In the interests of science .... I just connected one across a 12V car alarm 23A cell and it shrieks - if you pulsed it on/off then should probably be heard in next room :eek:

No problems with first post.
 
erco

erco

Senior Member
Hemi345 said:
Is anyone else having trouble with the first page of this thread? It redirects the browser to YouTube.

erco, have you run these at a higher voltage, say around 9V? I'm looking for something loud, like smoke/fire alarm loud that will be audible from another room or floor in a home. Tossing around ideas for building a water detector and want something loud.
Click to expand...
This works great, costs eight, go straight to the "Freight": http://www.harborfreight.com/water-overflow-alarm-92334.html
 
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papaof2

Senior Member
Pulsing works great. I did a blocked drain (potential basement flooding) alarm for one of my kids, using a PICAXE and a pulsing SonAlert. (See the water level alarm here: http://www.jecarter.us/picaxe/projects.html ).

The first time it went off was in the wee hours of the morning and they went hunting for "That #@&! beeping noise." The next time it went off, they knew what it was. Each time, it allowed then to clear the drain at the bottom of the outside stairs to the basement before the water got high enough to get into the basement door.

From the basement to a bedroom on the second floor is probably more distant than your "next room", so almost any slightly annoying sound that can be pulsed should work. The SonAlert is annoying, but definitely not as loud as a smoke alarm.
 
grim_reaper

grim_reaper

Senior Member
Has anybody tested these sounders over an open-air distance? I want to be able to (clearly) hear mine from about 20-25 metres away.

I would of course test the things myself, only China seems to be a bit busy at the moment, as mine haven't arrived yet!
 
erco

erco

Senior Member
If you need long range reliably, I'd pony up for a bigger buzzer. That said, expect to pay more than 18 cents. :)

IMHO this a great buzzer for amateur projects given the cost, size, reasonable volume, and use: driven directly by a 5V I/O pin. But for long range, mission critical apps, probably not.
 
grim_reaper

grim_reaper

Senior Member
It's not mission critical at all, I just haven't got around to building a wireless serial link, so a few loud bursts across the field will have to suffice for now!

My 7p each buzzers have still not appeared, so I've been forced to obtain some for the substantially increased price of 49p each!! Thankfully my accountant is on holiday this week. The spec says they have a maximum draw of 30mA and produce 18dB. I'll endeavour to post back here when I finally get something to test.
 
grim_reaper

grim_reaper

Senior Member
premelec said:
18db is hardly audible...
Click to expand...
I wouldn't go that far... it was enough to make the wife and kids nudge the TV volume up in the room next door :D
After refreshing my memory on dB (i.e. 80 is a plane engine, 60 a sports car, etc.) I realise you're quite right, 18 isn't much.
It will be fine for alerting me to critical (ish) alarms in various bits of circuitry, but for the remote monitoring stuff it's back to researching which wireless Tx/Rx pair will work best!
 
erco

erco

Senior Member
Edit: Connect these to +5V and sink the current through a pin rather than sourcing current through a pin, works much better, less voltage drop per http://www.picaxeforum.co.uk/showthread.php?27755-1-5v-voltage-drop-when-powering-20ma-load

My latest "practical joke" project uses one of these chirping like a cricket to lure someone into a blast radius. The buzzer makes a very realistic cricket sound:

Code: 
do
for b0=1 to 20
toggle 2
pause 13
next
pause 150
for b0=1 to 10
toggle 2
pause 10
next
pause 3000
loop
 
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