Bleeper that 'bleeps' when you whistle

[strikera]

Hi I have looked thorough many posts to see if I can find out about this, without success. Hopefully, someone can point me in the right direction. I have been to the electronic shops and asked - do you have a very small 'thing' - (I don't know much about electronics) - which will 'bleep' when you whistle.

Many thanks in anticipation of your help with this; much appreciated.

Dave

 

[alec_t]

You can buy key tags which respond to a hand-clap or whistle, for locating lost keys.

 

[audioguru]

You can buy key tags which respond to a hand-clap or whistle, for locating lost keys.

My daughter bought one then asked if I can fix it because it bleeped every time she talked or whenever the TV was playing. It did not bleep when somebody whistled.
It had a black blob IC so I couldn't fix it.

 

[alec_t]

Perhaps you have to whistle in Chinese

 

[dougy83]

I take it you want to buy the thing premade & not make it yourself? Here's one for US$2.20 including international postage. **broken link removed**

 

[Sceadwian]

These devices do not work very well, they have to constantly process audio information so their batteries do not last very long and as stated before they'll go off when you don't intend them to.

 

[strikera]

Many thanks guys

I am looking for something that does what you describe - but smaller, the size of a penny, or better still a five pence piece for my project. Perhaps this doesn't exist. If not, how do you make one.

Again, many thanks in anticipation of someones help.

Dave

 

[carbonzit]

To make such a device the size of a penny (I'm going by the size of our (i.e., North American) pennies here), you're going to need to somehow design and manufacture an ASIC (application-specific integrated circuit). Now, this is certainly within the realm of possibility, but really only if you have a sizeable research and development budget, and you're looking at making thousands or tens of thousands of the things. Otherwise, this is not a feasible DIY project.

 

[colin55]

You need this circuit:
**broken link removed**

 

[dougy83]

Hey Colin, what's the current consumption of that circuit? Just curious as the digital inputs are not necessarily near the rails.

 

[colin55]

I don't know what you mean.

Can you talk in "electronics speak."

 

[dougy83]

Can you talk in "electronics speak."

haha. Sorry. I'll try my hardest

[translate]>> Hey Colin, what's the current consumption of that circuit? Just curious as the digital inputs are not necessarily near the rails.[/translate]

Hey Colin, What's the current consumption of that circuit that you just posted when it's listening for a whistle? Just curious as the digital inputs (GP2/5) are held somewhere between GND & VCC (and not at GND or VCC).

 

[colin55]

The inputs only take microamps. The chip itself takes about 1mA or so.

 

[dougy83]

Ok, thanks. It was just that the pic datasheets bang on about the current consumption increasing if the digital inputs are connected to a voltage between GND/VCC. If the chip is taking 1mA, I guess the other leakage current is moot.

 

[Sceadwian]

So even with the base assumption of 1ma, a pair 2032 battery would last 9 days, and to meet the voltage requirements you'd need two which are out of the PIC's acceptable voltage range... I'd like to see the code for the PIC as well colin.

 

[dougy83]

The processor base current could be reduced to the microamp range by using sleep and the amplifier could be changed to use less current and provide a digital-compatible output. A single CR3032 could then run it for months.

 

[carbonzit]

But can you make it the size of a penny? (Or even of a nickel or quarter for that matter?)

 

[dougy83]

But can you make it the size of a penny? (Or even of a nickel or quarter for that matter?)

Not with a CR3032. You could get it smaller than a Nickel if you use a CR1216, but with 25mA.Hr, you'd only get 20 days if you can get the consumption down to 50uA.

 

[carbonzit]

I mean the entire circuit, not the cell. The cell alone is practically the size of a coin.

A roundabout way of saying that the O.P.'s stated requirements are a bit, shall we say, unrealistic.

 

[dougy83]

I meant the entire circuit. If a nickel is 21mm diameter x 1.95mm thick, you can fit the CR1216 (12.5mm dia x 1.6mm) and have space for the processor and amplifier (if used). The piezo would have to be <0.3mm thick and you'd likely want a acoustic chamber around the empty space in the thing so that you can actually hear the piezo beeping. So I believe it can be made around about the size of a nickel.