Hi, I need guidance and advice. I have to do IoT mini project, so i planned to do wearable device for child monitoring.
My project objective is
to track child's location (which i will use GPS)
to trigger an alert to parents' if the child's distance is too far away,
--- for example set maximum distance range 10M, so if the child distance is more than 10M, it will trigger.
The alert will be in form of buzzer and also, notifications on smartphone.
So, my question is, what sensor is the most suitable for my 2nd objective? If possible, budget friendly for student too.
Currently, I am planning to use Ultrasonic sensor (HC-SR04), through some research, i found that its range is maximum 4M. But, is HC-SR04 possible to meet my 2nd objective?
If not, can anyone please recommend my any other sensor?
Any suggestions or advice is very appreciated, thank you in advance!
Update: After reading more and more, I think I am going to use Bluetooth module for 2nd objective. The limitation that I am aware of is the interference, any more advices?
the child could carry an ESP32 running a WiFi access point
such APs have a limited range (depends on environment such as walls, trees, etc)
the parent connects their smartphone which runs an app which makes contact with a the AP at regular intervals - if the contact fails the app raises an alarm
add a GSM modem to the ESP32 - the parent could call the modem which returns the child's location - assuming it has GSM and GPS coverage
Interesting project. But have I understood correctly: is this two projects: a long distance one, requiring GPS, and one within your home and/or garden?
Choosing a sensor for the latter is likely to need some experiment. And, as you’re already aware, avoiding unwanted triggering is one significant challenge. Will the child always be in an area otherwise unoccupied? Such as by adults and pets?
One candidate would be a PIR. The one I used a couple of years ago seemed to trigger at distances close to your 10m (with a fox as its target). Also consider an IR transmitter and receiver. The devil as usual will be in the details.
BTW, I would definitely avoid any solution requiring a device to be ‘carried’ by the child.
Parents and child in busy public areas such as malls, outdoor parks.
As this project aim to ensure the safety of the child when going out with parents.
Thanks for you suggestions, I will look deeply into the PIR and IR. I've tried PIR before, but I am not sure if it is really capable of being triggered as soon as the child is out of the maximum range. As my 2nd objective is, for example, it will only be triggered if the 'child' wanders too far away from 'parents', which is out of the safe distance.
For this project, I will be demostrating this project in my classroom which is not so big, so maybe the interference would not be a problem.
Anyway, I really appreciate your response and suggestion! Thank you so muchhh
