ChildReminder

Amit Marcus

Why?

In the past 9 years (2008-2016) in Israel only there were 381 cases of children who were forgotten in a car, from which 19 cases ended in death (Bizzness, Hebrew Wikipedia).
This can be easily prevented by alerting the driver of a forgotten child in the rear seat, exactly here Child Reminder enters the game.

Demo

ChildReminder device

Hardware

• CC2650 LaunchPad
• 1x 4k7Ω Resistor
• Force Sensitive Resistor 0.5"

Software

• Detecting sitting child:
• Decided by reading the voltage of the pin connected to the sensor (DIO23) - child is sitting if above 0.5V.
• The reading is executed by using the ADC of the CC2650 (every 2 seconds):
• AUXWUCClockEnable - Enable clock for ADC digital and analog interface.
• AUXADCSelectInput - Connect AUX IO7 (DIO23) as analog input.
• AUXADCEnableSync - Set up the ADC (AUXADCDisable - to disable).
• Power_setConstraint - Disallow STANDBY mode while using the ADC (Power_releaseConstraint to allow again).
• AUXADCGenManualTrigger - Trigger ADC sampling.
• AUXADCReadFifo - Pop sample from FIFO.
• HWREGBITW(AUX_EVCTL_BASE + AUX_EVCTL_O_EVTOMCUFLAGSCLR, AUX_EVCTL_EVTOMCUFLAGSCLR_ADC_IRQ_BITN) = 1 - Clear ADC_IRQ flag.
• Sending the information:
• Using bluetooth - only through advertisment (without full connection) (GAPRole_SetParameter(GAPROLE_ADVERT_DATA, sizeof(advertData), advertData)).
• Advertisment interval is 2 seconds - 1 second of advertismenting and 1 second of waiting.

ChildReminder client

Android

• Starts at boot time (BroadcastReceiver listens to android.intent.action.BOOT_COMPLETED).
• Operates as background service (extends IntentService).
• Scan near bluetooth devices (BluetoothLeScanner) every 20 seconds (AlarmManager which calls the service) to detect the device and get the information.
• Alerts the user with notification and sound when child was forgotten in two cases:
  • Lost connection with the device after detecting a child in the seat.
  • Rssi becomes lower then -90 after detecting a child in the seat.
• Simple UI with updated information from the ChildRemider device: