alarm to track child

[mampmamp]

I want to make an alarm to track my child in very noisy places and with many people.
The system would consist of two parts, one is secured on my hands and the other is with the child. the operation would be simple, eg parent and child are in a busy store, the child suddenly vanishes, then the father takes the device out of his pocket and presses a button, then the device that the child emits a loud sound too high, ready , ie as if the child had given a loud scream, and then only locate Where'd came the "scream". This device would make my life better.
I have experience with programming in assembly, and little in electronics.
If someone can help me thanks.

[dr.diesel]

You need this.

[Dave]

This comic comes to mind:

[c4757p]

Don't children already emit loud sounds, like, every thirty seconds or so?

You could pretty much rig any RF-controlled battery operated pair of devices to do this. So dr.diesel wasn't far off, just shove a buzzer in there instead of the high voltage generator...

Doing it entirely by yourself would be much harder, there's a lot to consider when making even a simple radio-transmitting device.

[dfmischler]

Why build what you can easily buy?

GPS dog locator

Child locator products

[Len]

Don't children already emit loud sounds, like, every thirty seconds or so?

Yes, but the latency is too high. It's amazing how much trouble a kid can get into in 30 seconds. 

[pickle9000]

How about a keyfinder?


http://www.ebay.ca/itm/No-Radiation-1-To-1-Anti-Lost-Alarm-RF-Wireless-Super-Electronic-Key-Finder-/390724376310?pt=US_Surveillance_Gadgets&hash=item5af8fcd6f6

[mampmamp]

the keyfinder would be cool, but I need to amplify the sound signal. for me, amplifying the signal is easy, the problem is to get  enough tension for the sound to be very high. I thought of using a battery of mobile phone, but the maximum decibel I'll get will be equal to own maximum ringer volume of mobile phone. but i need a higher sound than that...

[Dave]

I thought of using a battery of mobile phone, but the maximum decibel I'll get will be equal to own maximum ringer volume of mobile phone. but i need a higher sound than that...

Nope. Battery voltage does NOT dictate the maximum volume of your mobile phone's speaker.

[mampmamp]

what dictates the maximum volume?

[lapm]

When i was child there was this lowtech solution: Harness that is put on child and long lease attached on it.
https://www.google.fi/search?q=child+harness

Alto even cheaper solution would be pay attention what your kid does and teach him to stay close...

Sorry, could no resists, dont take my advice too seriously.. Has been hard day and im bit on edge...

[lapm]

what dictates the maximum volume?

proximity to candy section of store i would imagine based on my own observations..

[AG6QR]

what dictates the maximum volume?

It's a matter of power, not voltage.  Current, impedance, and speaker efficiency enter into it.


Suggestion: assuming you really want to do this, consider making it so that the parent's unit transmits a coded signal every 5 seconds or so.  The child's unit can be set up so that, if it misses more than two or three consecutive pings from the parent's unit, the alarm sounds.  The button on the parent's unit can either be designed to shut off the "ping" transmissions, or can transmit a different code which means "alarm immediately".

The idea is, if the child's receiver gets out of range of the parent's transmitter, the alarm would go off regardless of whether the parent pushed the button.


Though I'm a parent myself, and while my kids have been separated from me in public a few times, I don't think I'd go for a technological solution.

[mampmamp]

Thanks AG6QR, my son is an autistic boy, the relationship between father and son in this case is quite different.

I already bought a device that works identical to your suggestion, unfortunately does not work for this type of situation (situation as I described above)

I need an autism parent (that seems like no one understands that situation, hehe), which is in the same situation as me, and like my idea, and like electronics too, so that together we can do, alone it is very hard for me. meet someone like this, i think, is very hard too.