Smart Safety Seat

Guy Layfer, Arthur Furmanovsky


Recently, the number of incidents where parents forgot their baby in the car has grown,
and unfortunately those incidents included hard injuries or death of the baby.
The average price of a high quality safety seat in Israel is about 1000 NIS.
Despite the high price, there is no safety seat that solves the problem of forgetting a child inside the vehicle.


Our Goal

To find a cheap and smart solution to the problem and by that convince
the safety seat companies to implement such a system in their seats.


The Solution

An Arduino based system that alerts the driver in case he left the car and forgot a baby inside it.



The Project In Detail


  • Arduino Uno board.
  • HC-05 Bluetooth module.
  • keychain with Bluetooth device.
  • Force Sensitive Resistor (The Weigh Scale).
  • Piezo alarm.



The system runs a loop in which it checks if there is a baby in the safety seat using the weigh scale.
If there is a baby in the seat, the system checks if the Bluetooth device of the keychain is around by a Bluetooth inquiry.
If the keychain is not around, the system activates the alarm.
The system deactivates the alarm when it identifies the keychain in the Bluetooth inquiry or when the baby is picked up from the seat.
While there is no baby in the safety seat, the system is in ‘sleep mode’ and it does not perform Bluetooth inquiry.





HC-05 Bluetooth module:

To configure the Bluetooth module so that it could make Bluetooth inquiries, we had to
change some of its settings, like its role for example (from ‘slave’, which is default, to ‘master’).
To do so, we had to connect it in ‘AT Command mode’ which enables the use of a specific
commands set (AT Commands) that changes the module settings and enables inquiries.

We connected it in the following way:

(Image Taken from


Keychain with Bluetooth device:

We disassembled the Bluetooth device from a Bluetooth speaker,
which came with a small rechargeable battery,
and we entered it into a small earphones case which we used as a keychain.
In addition, we wrapped the Bluetooth device with aluminium foil
in order to reduce the range of its discoverability to 5-6 meters.


Weigh Scale:

For the weigh scale we used a 12.7mm Force Sensitive Resistor which should be connected with a 10kOhm resistor in the following way:

(Image Taken from

In addition, We crafted a weigh scale from two plastic plates using small sponges to absorb some of the pressure on the plates.
We chose the plates by size so they could fit underneath the safety seat cushion.


Final Structure:



Useful Links

Arduino Language Reference

Force-sensitive Resistor Wiki

Force Sensitive Resistor + Arduino

Bluetooth Roles


Using the HC-06 Bluetooth Module

HC-05 AT Mode tutorial

HC-05 AT Command Set


Contact Us

Guy Layfer:
Arthur Furmanovsky:

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