Automatic E-Baby Cradle Swing Based on Baby Cry

International Journal of Computer Applications (0975 – 8887) Volume 71– No.21, June 2013

Automatic E-Baby Cradle Swing based on Baby Cry Misha Goyal

Dilip Kumar

ACSD, CDAC Mohali, Punjab INDIA

ACSD, CDAC Mohali, Punjab INDIA

ABSTRACT There is a need to develop a new low cost indigenous electronic cradle because the existing cradles are imported and costly. This paper presents the design and implementation of a new indigenous low cost E-Baby Cradle that swings automatically when baby cries, for this it has a cry analyzing system which detects the baby cry voice and accordingly the cradle swings till the baby stops crying. The speed of the cradle can be controlled as per the user need. The system has inbuilt alarm that indicates two conditions – first when the mattress is wet, which is an important parameter to keep the baby in hygienic condition, second when baby does not stop crying with in a stipulated time, which intimated that baby needs attention. This system helps parents and nurses to take care of babies without physical attention.

General Terms E-Baby cradle, low cost, indigenous.

Keywords Automatic Baby Cradles, Wet Sensor, Cry Analyzing System.

1. INTRODUCTION Parents in the present world are busy in their professional life, so they do not get sufficient time to take care of their babies. It may be expensive for the household to afford a nanny. Today’s woman has to manage home along with their office work simultaneously. After long working hours, they have to take care of the home along with the baby. They may not get enough time to swing the cradle manually and sooth the baby. Moreover, in today’s life style, it is very difficult even for the housewives to sit nearby their infants and sooth them whenever they cry. Hospitals have neonatal and maternity units. Nurses in these units have to take care of baby and sooth them whenever they cry. The system is designed to help parents and nurses in infants care. The design aims at following points: 1. Cradle starts swinging automatically when baby cry and swings till the baby stops crying. 2.

Sounds an alarm when mattress gets wet.

3. Sounds an alarm if baby cries for more than a stipulated time indicating that baby needs attention.

2. RELATED WORK Steven Bang designed automatic baby rocker having a noise sensor to detect baby cry. Noise sensor consists of Electret MIC with a pre amplifier (2n3904 transistor). Signal from noise sensor is fed to microcontroller Arduino ATmega 328, which is used to control the DC motor. Few colorful lights made up of LED are used to entertain the baby while being rocked. Mabuchi RE-260RA DC motor with Tamiya 6 speed

gear box is used to create the rocking motion of the crib with gear ratio of 505.9:1 [1]. Yang Hu proposed an algorithm for adjusting the bassinet swaying extent by the sensor signals. The bassinet is made up of an adaptive swaying device and other sensors network. While baby is crying, the sensors network can judge the reason according to detecting parameters, giving the different signals to control circuit. At the same time, the bassinet starts to sway slightly. The swaying rhythm can be adjusted according to parameters from baby status. They used three pressure sensor located in the bassinet bottom, one at the centre and others at left and right of the bottom [2]. Marie R. Harper invented a crib adapted to be rocked automaticaly. Once the crib is manualy tilted in one direction and released, this permits the inertia to actuate the locking and actuating arms to operate under the biasing force of spring in conjuction with the gear. Thus spring loaded motor begin to operate and the lever arm is oscillated in back and forth movement. This provides the same effect as would be achieved by the mother rocking the crib containing the baby. Oscillation of crib is stoped when the slightest resistance is incurred [3]. Gim Wong presented an Electronic device that can be attached to conventional pivotally mounted type crib. Which is actuated by baby cry voice picked up by the microphone giving short throw type rocking action to crib. Very similar to a person rocking the crib by pushing and pulling on the foot or headboard . There is a sensitivity control so that baby voice only actuate the rocking action and a timer to controlle the duration of rocking action [4]. Chau-Kai-Hsieh proposed a baby cry recognizer which includes an amplifier circuit for amplifying a received sound signal. In response to the amplified sound signal, a pulse generator circuit generates a pulse signal having zero crossings which are aligned with zero crossings of the amplified sound signal. The pulse signal, in turn, is inputted to a signal recognition circuit. The signal recognition circuit outputs a signal indicating that a baby’s cry was detected [5]. Anritha Ebenezer gives an aproach to design a baby cradle consisting of cry analyzing system which detects baby cry. According to sound intensity cradle swings. It has six rocks per minute. It has wet sensor to indicates baby wets, whenever baby wets resistance would change thus sending a signal. Other sensors include temperature sensor to display baby temperature, respiratory sensor that sends a signal in apnea condition. GSM modem via RS232 is used to send msg to parents in case baby does not stop crying with in a particular instant of time [6].

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International Journal of Computer Applications (0975 – 8887) Volume 71– No.21, June 2013

3. BASIC PRINCIPLE

Wet Sensor

Alarm

Principle behind cradle swing stays in comparing the baby cry generated sound level in dB 𝑥 with a preset value 𝑦 and it swings if 𝑥 is greater than 𝑦. Signal conditioning

The amplified signal is generated from the voice input. This amplified signal is then converted into a digital signal from which sound level 𝑥 is calculated. 𝑣𝑖𝑛 𝑠𝑜𝑢𝑛𝑑 𝑙𝑒𝑣𝑒𝑙 𝑥 = 20 log 𝑑𝐵 𝑣0

µc

Driver Circuit

Motor

Baby Bassinet

MIC

Where, Fig 2: Block diagram of E-Baby Cradle

Vin = Voltage (ADC count) when baby is crying. V0 = Average reference voltage (ADC count) when baby is not crying. The preset value 𝑦 is set initially as part of configuration of the system. It is the least value among the samples of baby cry sound levels and it can be modified in future as and when necessary.

4. ALGORITHM Start

Incoming signal value is (x)

When baby cries in the cradle, microphone detects it and converts the sound signal into electrical signal. The electrical signal is then fed into amplifier. Condenser microphone is used to detect the baby cry. This has two plates and one of these plates is made of very light material that acts as a diaphragm. The diaphragm vibrates when struck by sound waves, changing the distance between the two plates and therefore changing the capacitance and producing electrical signal. Op-amp is used as amplifier for signal conditioning circuit. The electrical signal from MIC is provided as input to the circuit. The output from MIC is get amplified by op-amp so that it can be used by microcontroller.

No

value (y)

5.1 MIC

5.2 Signal Conditioning

Take samples of sound level from baby cry

Input least value from these samples as preset signal

The main designing blocks of system are as follows:-

Is mattress wet?

Yes Alarm

No

5.3 Wet Sensor It is a moisture sensor having two leads in mesh form. One lead is connected to microcontroller through pull up resistor and other is connected to ground. When baby wets the mattresses the two leads become short and signal is send to microcontroller. This microcontroller in turn sends the signal to the alarm. This system helps in keeping the baby in a hygienic environment.

5.4 Microcontroller PIC16F73 is used to receive the amplified signal and to convert this amplified signal to digital signal. Microcontroller controls the driver circuit that starts a motor and sways the baby bassinet according to the input signal.

Is x>y?

Yes

5.5 Alarm

Swing cradle

Alarm will be generated on two conditions: Yes

1. When mattress is wet, indicating parents that mattress and baby clothes need to be changed. 2. When baby cries for a specific time. For example, baby cries and baby bassinet swings for 2 min alarm will be generated. This indicates parents that baby needs attention.

Is swing time (t)>2 min & x>y?

5.6 Driver Circuit Motor driver circuit supplies essential power to drive the motor. This isolates the PIC and ICs from electrical problems.

No

5.7 Motor

Stop

Fig 1: Flowchart

5. BLOCK DIAGRAM Fig 2 shows the basic block diagram build around PIC16F73.

Heavy duty sewing AC motor of 8500 RPM, 220 volts is used to sway the baby bassinet. It is connected to PIC through a driver circuit. Also, motors tend to be electrically noisy (spikes) and can pass power back into the control lines when its direction or speed is changed. This EMF is created by

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International Journal of Computer Applications (0975 – 8887) Volume 71– No.21, June 2013 motor brushes. The driver circuit protects PIC from back EMF.

5.8 Baby Bassinet Baby bassinet is the infant bed. This is connected to a motor which sways the baby bassinet based on the power it receives from the driver circuit.

6. DESIGN OF CRADLE Design of E-Baby Cradle is a challenge in itself. The system is designed so that baby feels comfortable and gets a good sleep. It can be used for babies aged between 3 months to 2 years. Mechanical design is such that it provides smooth and gentle rhythmic motion just like parents manually swings the cradle. Also, when cradle stops swinging it does not give jerks to baby. As shown in Fig 3 and Fig 4, baby bassinet is made of wood with dimensions: length 90cm, height 25cm and breadth 49cm. Bassinet is mounted on mechanical system which consists of base frame, motor, connecting rod, roller and a belt. Motor has a small drive roller with diameter 2cm. The motor drives larger drive roller with diameter 40cm which reduces rpm and gets desired torque. The larger wheel is connected to base of bassinet with connecting rod. The mechanical system has low wear and tear and requires less maintenance.

Fig 4: Top view of cradle design from an angle Fig 5 shows the electronic board connected to cradle which consist of transformer, microcontroller and peripheral devices including LCD, op-amp, wet sensor, relay and switches. A transformer steps down 220V AC to 15V AC. Further LM7805 steps down 15V DC to 5V DC which inputs to microcontroller and other peripherals.

Fig 5: Electronic board connected with cradle

Fig 3: Top view of cradle design

Fig 6 shows the circuit diagram. Two OP-07 op-amps amplify MIC output, which is connected to RA0 pin of microcontroller. Two switches are coupled to RC0 and RC1 pins of microcontroller to set the preset value. A 16 x 1 LCD is connected to PORT B that shows the sound level of baby cry voice and also shows preset value set by user. Wet sensor is connected to RC2 pin and motor is connected to RC7 pin through driver ULN2803 and relay. Buzzer is connected to RC5 pin through ULN2803.

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International Journal of Computer Applications (0975 – 8887) Volume 71– No.21, June 2013

Fig 6: Circuit diagram

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International Journal of Computer Applications (0975 – 8887) Volume 71– No.21, June 2013

7. TEST RESULTS

8. RESULTS

We show test results of a real example in the section. The developed prototype is shown in Fig 7.

Here one baby boy of 7 months old and another baby girl of 6 months old are considered for the analyses of their cry voices. Three samples of each of the baby cry voice are taken at different instant of time. The voices are recorded in .amr format and then the sound level generated from these voice signals is analyzed. From analysis it is identified that each baby’s cry voice sound level varies. Thus accordingly the system is to be configured first time by setting the preset value. This system is so user friendly that user can preset the value himself. Table below shows the different sound levels. Here absolute values are taken. Table 1: Sound levels

Sample 1

Baby Boy (dB) 23

Baby Girl (dB) 33

Sample 2

21

30

Sample 3

25

36

Samples

Fig 7: E-Baby Cradle Here three samples of sound levels of baby cry voice sound level are taken i.e. 24dB, 27dB and 21dB. Least value 21dB among the three sound levels is set as preset value. Now in Fig 8, baby is quiet. Even when the baby is quiet there is an input due to environmental noise ranging 0dB-5dB which is less than the preset value 21dB and therefore cradle does not start swinging.

9. CONCLUSION Looking after babies is hard problem worldwide. Babies are society future. This system emphasizes the importance of child care. The above designed system is economical and user friendly and very useful for working parents and nurses. They can manage their work efficiently. This system can be enhanced with more features like baby rotating toy with music and camera. Parents can monitor their baby live via 3G. With the development of technology day to day work has been eased for parents along with baby care. Otherwise, mother’s lap would be best cradle for baby.

10. ACKNOWLEDGMENTS This work is supported by CDAC (Center for Development of Advanced Computing) Mohali, India. I am thankful to Mr. J S Bhatia and Dr. Dilip Kumar for their support and guidance. Fig 8: Baby is quiet When baby starts crying as is Fig 9, an input due to baby cry voice and environmental noise is detected in range 25dB35dB which is greater than the preset value 21dB and therefore cradle starts swinging. When baby stops crying, cradle stops swinging slowly so that baby totally goes to sleep.

11. REFERENCES [1] Steven Bang; Richard Lam; Natallia LoCicero; , “Rock Me Baby: The Automatic Baby Rocker” Project for, San Jose State University, Department of Mechanical and Aerospace Engineering, May 17, 2011. [2] Yang Hu; Weihua Gui; , “Adaptive Sway Control for Baby Bassinet Based on Artificial Metabolic Algorithm” School of Information Science and Engineering, Central South University, China. [3] Marie R. Harper; La Mirada; Maxine R. Blea; , “Automatically rocking baby cradle”, US 3769641, Date of Patent: Nov. 6,1973. [4] Gim Wong, “Automatic baby crib rocker” US 3952343, Date of Patent: Apr. 27,1976. [5] Chau-Kai-Hsieh; Chiung Lin; Taiwan; , “Baby Cry Recognizer” US 5668780, Date of Patent Sep. 16,1997.

Fig 9: Baby crying

IJCATM : www.ijcaonline.org

[6] Anritha Ebenezer; Anupreethi. S; , “Automatic Cradle Movement for Infant Care” Undergraduate Academic Research Journal (UARJ), ISSN : 2278 – 1129, Vol.-1, Issue-1, 2012.

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