HELP pls, I learn to build ANTI LOST ALARM

HI, its simple project, and i bet this unit already in any online shops. But i want to try build it on my own, before i just buy it (since its already sold out in my online shop :o )

I prefer use bluetooth.

I was planning to make an anti lost item, which is basically an unit you put in your bags or keychains and it alerts you when u away from the bag or keychain (lets say 7-10m).

So basicly they will ping each other as transmitter and receiver, and when system no longer receives any ping (disconnect), so the alarm (buzzer) will actived

Is there anyone here who has worked on something similar or own a device similar to these? Because i wanna learn how to make it (i wish i could learn from arduino code). Or i will buy it with same requirement :smiley:

If the units already in online shop, its okay just sharing in here so i could think about it.. :slight_smile: :slight_smile:

HI, its simple project

In concept, but not in practice. For one, battery size and life is a terrible problem.

And yes, you can buy these things.

Transmitter sends off a signal every 30 seconds or so. Receiver resets a countdown when it gets the signal. If it succeeds a countdown, sound alarm.