ABOUT
This is an individual project that I worked on at the Physical Computing & Prototyping class.
The concept is to help busy parents to take care of their baby remotely. Parents get updated information from the system via various sensors. Once it's detected that a baby is crying, parent can select a pre-loaded song from the system to play, in order to comfort the baby. The system also connects with the smart home hub, and will ring alarms when danger is detected.
ROLE
System Design, Programming, 3D Modeling
The video shows how the system reacts to different situations with the use of sensors and actuators.
Envision Scenarios
A young professional couple and a 2-month-old baby live together in a house. The parents are very busy. Sometimes it happens that the baby is alone in the room sleeping. However, the room is smart enough to help the parent monitoring what’s happening in the baby’s room, with the possibility to take appropriate actions if emergency happens.
(Image Credit, left: http://nlalorphotography.com/blog/aubreys-natural-newborn-session-fairfield-ct right: http://changingculture.com.au/checklist-are-you-a-real-man/)
Map Out 3 Interactive Behaviors
Interactive Behavior No. 2:
The system keeps detecting the noise level in the room, and enters the “baby is crying” mode when the room become noisy.
Sensor:
Microphone
Actuator:
Music player
Software:
The system collects the analog data get from the microphone for a window of 50ms, saves the maxim and minimum data, and calculates to get the peak-to-peak number. If the peak-to-peak number is larger than a certain limit, it will trigger the “baby is crying” mode. The system will send the alert message to the smart home gateway. And the music player will play the pre-loaded alarm “ the baby is crying, select a song to play” (in a real scenario, this alarm will be sent to the parent’s smart devices as text-messages). At the same time, the noise indicator, red LED will start blink.
Message to Gateway:
"Room becomes noisy, the baby's crying."
NOTE: The Adafruit Music Maker MP3 Shield 's fritzing component couldn't be found on the Internet, so it is missing from the breadboard view. The green LED (indicator for playing music) is also missing because it is directly attached on the music player shield. They should be directly mounted above the Arduino component.
Design Software (Coding) in Arduino
The key of the software design is to evaluate the current status with “if” statement, and decide which “mode” to enter, for example, the mode of “detecting noise”, “waiting to select songs”, “song selected” and “playing songs”. Within each “mode”, certain sensors are activated while others are deactivated, the “while” statement is used to execute certain actions within each “mode”.
Another important part of the software design is interruption. Because of the inhabitant constrains Arduino has, it is not very easy to have Arduino done several things at the same time. It is important that the music player component has the available function to play music in the background while the software keeps running.
Looking Back
Overall, I am very happy with the final prototype. It couldn’t be true without people around me helping me through the process. It is a wonderful opportunity to learn about Arduino, and the computing world. I will definitely keep learning about it in the future. Here are my reflections on what went well and what not:
Good Scope and Time Management
The biggest success of this project is that I successfully prototyped the core functionality with a very limited schedule. Because of the full-time internship and travel, I have to finish all the digital and physical design a week earlier than others. It was a challenge for time management, but I was able to finish the work without sacrificing too much sleep.
After discussing the project plan with the instructor, I cut off some features, such as the camera, which allows parent to see what’s happening in the room, and the LED indicator for sending the signals. It turned out that the instructor was right about the scope of the work – he suggested me to add the camera at last after I finished all the other design.
Laser-cutter is Gold, and I Really Enjoy Making Things
Another success of the project is that I made the physical part of the room by myself with the help of laser-cutting technique. I learned to use the laser-cutting machine for the first time, and it turned out to be great fun. I know the 2D and 3D softwares needed for laser-cutting, but had never got the opportunity to try it by myself. With the help of the staff at the maker space, I learned how to use it and even make some gifts for my co-worker during my last day at the internship. I really enjoy making things! Thanks this class for introducing those great resources to me.
Frustrating MP3 Shield and Compromised Solution
The desperate part is that I didn’t expect the MP3 shield would take so many pins the Arduino has. Even though it looks like I didn’t include many components to the system, but the fact is that I had taken all the available pins that is not affected by the MP3 shield. That’s why I have to compromise to use the awkward gesture for “pressing two buttons at the same time” to stop the songs – there isn’t an available pin for adding another stop button.
The XBee component couldn’t find an available pin either. The MP3 shield affected the XBee to function properly because it uses pin 2 and 3 for other purpose and this couldn’t be rounded. I took this problem to a co-worker of mine, who is very skilled at Arduino. We tried to figure out a way to solve this problem, but all of them failed. The result is that the entire alert the XBee can send and receive doesn’t actually work. I faked that in the video just for demonstration purpose.
Read another case study
SMART BABY'S ROOM
To design and build a physical prototype for a smart home system
TEAM
Lingshuang Chen, Designer & Prototyper
Andy Davidson, Class Instructor & Smart Hub Designer
TIME
11/2015 - 12/2015 (3 weeks)
IMPACT
For the first time I played with Arduino and learned the programing language, it was so fun. I also learned using the laser cutter on campus, which makes me fascinated with making physcial prototype of my own design work.
HOW THE SYSTEM WORKS
HOW I DESIGN IT
or, Back to Work
Start with System Diagram
The diagram illustrates what components are needed for the whole system to work. I went through some iterations to keep the project in scope based on the availability of materials, time and effort. The wireless receiver(smart hub) was developed by the instructor, anything else was developed by myself in parallel.
Interactive Behavior No. 1:
When the baby is crying, the system keeps detecting if any button is pressed. The music player will play the corresponding music if a button is pressed.
Sensor:
Two button
Actuator:
Music player
Software:
While the red LED is blinking, the system keeps detecting if any button is pressed. If a button is pressed, the music player will play the selected file stored in the SD card in the background, allow the loop keep running while the music is playing.
Message to Gateway:
"The song you selected is playing"
Interactive Behavior No. 3:
When music is playing, parent can switch or stop the music by pressing the buttons.
Sensor:
Two buttons
Actuator:
Music player
Software:
While the music is playing, the microphone (noise detector) stops working. If the system detects another button is pressed, it will stop and start playing another selected music. If the system detects two buttons are pressed at the same time, it will stop playing songs. The microphone then starts working again.
Message to Gateway:
"Room is quite, the baby stopped crying."
Sketch Circuit Diagrams
In visualizing the circuit board of my design, I drew hand sketches and iterated for several times. The iteration happened together with tinkering with the real circuit board and iterating on the code.
Build a Room for the Baby
I designed the room and the furniture in a 3D software Rhino. From the 3D model I generated the files for laser-cutter.
The Gallery
Here are some documentary pictures for the process and the final prototype.
