Makerspace - Iron Chef Challenge - Motor and Sensor!

1. Project:

For this week’s challenge, we took on the "Iron Chef Challenge" of creating something using motors and sensors. I was inspired by the idea of creating a dancing baby Groot! Embracing the true maker's experiences, I did a lot of prototyping, building and rebuilding. I played with all three of the motors that came with my kit! And ultimately, my project morphed from a dancing baby Groot to a chill baby Groot spinning his favorite record on his finger tip!

Original Inspiration: Dancing Baby Groot!

2. Code:

This is the code I developed this week. It uses what I learned about the ultrasonic sensor last week to turn on the DC motor (for a minimum of 3 seconds) when something is within 10 centimeters of the sonar detector.

3. Circuit Design:

The following described my circuit design for the DC motor triggered by the sonar detector.

Video of Circuit for Iron Chef Challenge (0:36)

4. Electronic Diagram:

The following electronic diagrams were taken from my design journal.

For the following circuit design, the sonar sensor detects distance, and the LED function as indicator by turning on when the motor turns on, the resistor, transistor and diode arrangement function mainly to protect the Arduino from any excess surges in current or voltage caused by operating a spinning motor. 

When motors spin up, they store energy in the form of rotational inertia. If the load on that motor is suddenly increased or decreased, the changes in rotation inertia can cause surges in electrical current. To protect the Arduino, we're using a PN transistor to separate the signal pin (D3) from the motive force (V5). We use the resistor to limit the current from the signal pin (D3). And we use the diode to ensure that the current from the motor can only travel in one direction.

Electronic Diagram for Iron Chef Challenge

5. Video of Project:

Description of Baby Groot Iron Chef Challenge Project (5:51)

6. Explanation of Project:

As shown in my video above, this week's challenge pushed the limits of what I could accomplish with my Arduino kit and the random recyclable materials around my house. Like any great Iron Chef, I embraced the drama of setbacks and successes, ultimately adapting my design to better showcase my "ingredients", despite my original vision.

While my paper towel roll / coat hanger / card board / rubber band design for a wobbly Groot body with waving arms was off to a good start, I ultimately discovered that the friction of the rotating parts was going to exceed the torque of any of the three motors that came with my kit.

After careful review of each of the motors (stepper, DC and servo) and their capabilities, strengths and weaknesses, I ultimately decided that, given the supplies and time I was working with, it would be better to change my design to better match the capabilities of one of these motors. I wanted to stick with the music / dancing theme, so I thought of adding a spinning record disk to the tip of baby Groot's finger. The best motor choice for this action was the DC motor.

I wanted to use what I learned last week about ultrasonic sensors and apply it to this project. I started by figuring out how to turn my DC motor on and off. (My LED indicator light came in handy here, because I was able to see that I was sending current to my motor, but it wasn't turning on! Upon further investigation, I didn't have my 5V and ground wires plugged in correctly.) Next, I incorporated my ultrasonic sensor code so that the motor turned on (for a minimum of 3 seconds) whenever something was within 10 centimeters of the sonar sensor.

My final step was to incorporate the electronics into my physical model! I used the extender wires that came with my kit, and ultimately my baby Groot starts spinning his record whenever you come close!

Video Demo of Final Baby Groot Project (0:28)

7. Reflection:

The project was by far my most challenging and time consuming! That said, I absolutely love my creation. Apart from that, I think it showcases what makes a good maker's project -- something that motivates a maker to extent her abilities in the pursuit of creating. I was driven, not by an assignment, but my own vision of what I wanted to accomplish. Ultimately that vision changed and morphed throughout the design. The result was that I learned by doing, making and creating in a process that I thoroughly enjoyed. I can't wait for opportunities to share creative processes like this with my students!

8. Applications:

With holiday decorating in full swing, there are obviously lots of sensor-triggered dancing, singing, whistling, spinning, rocking and rolling snowmen, Santa's, elves, stockings, reindeer and more on every shelf, mantle and window sill around. Digging into the guts of these might be a fun reverse engineering project for students to try! Maybe I can find some on sale after the holidays to use for dissection projects next year!!