Staff Spotlight: Karen Stirling

Bringing Life To PDC!

Karen is the Yoga, Art, and Nature Education teacher at Paradigm Development Center (PDC). She is also an avid naturalist and animal lover. Her heart for the wellness of others and the Earth is valuable and effective within the PDC school environment. She has inspired us to see things in the Earth that need to be seen.

Due to her vision and effort, this year PDC will be hosting Monarch butterflies migrating from Mexico. Karen has spent hours taking courses and researching which specific plants would be most beneficial to host the butterflies as they migrate through Texas destined for Canada. She taught the students how to recognize eggs and distinguish larval (caterpillar) instars of Monarch butterflies. She also instructed on Monarch anatomy, possible extinction due to environmental factors, lifecycle, and migratory patterns. She walked each student through the cold stratification process and talked with them about how important milkweed is to Monarch butterflies (Milkweed is the only food Monarchs eat.). During this hands-on activity, she showed them how to successfully cold stratify milkweed seeds.

Monarch Butterly / Sensory Garden 

The Project

Karen is leading the planning, organizing, and building of the PDC Monarch butterfly/Sensory garden that will be hosting migrating Monarchs. Thus far, she and her volunteers have planted Pentas, Lantana, Black-Eyed Susans, Copper Canyon Daisy, Blue Porter Weed, Jasmine, a variety of milkweeds, Pineapple Sage, Cherry Queen Autumn Sage, and Salvias. They have also planted a Gala apple tree and a Ponderosa lemon tree.

A couple weeks later, after all the plants were planted, Karen decided to dig some of them back up so she could put more dirt down. She was concerned that a strong rainstorm may flood the plants, so she raised the plant mounds by two-feet and installed garden fences around each mound.

We will write a follow-up blog post highlighting the garden building process. Check out pictures and videos below!

Robotics Club: March 22, 2019

What Did We Do?

We started this week’s session with the introduction of the new challenge.

We defined our new challenge as “Design a robotic car that can climb the steepest incline”.

The learning objectives for accomplishing this challenge are to learn and apply the principles of: 

Gearing Up and Down

• Video

Center of Balance

•  (COB) is a point with respect to which the object in question is balanced with respect to applied forces.

Weight Distribution

• Weight distribution is the apportioning of weight within a vehicle, especially cars, airplanes, and trains. Typically, it is written in the form x/y, where x is the percentage of weight in the front, and y is the percentage in the back.

Torque vs. Speed

• Torque is a twisting force that tends to cause rotation.

The Steps

We first let the builders test their original robots on the incline to give us a baseline of the abilities of robots that were designed for other applications. We quickly pointed out that ALL of our robots were able to manage some degree of incline.  This gave us the opportunity to then introduce the key elements of succeeding in this challenge. We contrasted our previous designs with the variables of an effective design structure for this specific challenge. 

First, we watched a video on Gearing Up and Down and discussed the trade-off between speed and torque. After that, we quickly discussed the Center of Balance (COB) and how the combination of it with Weight Distribution would help us avoid tipping over AND not sliding on the surface of the incline. 

One builder quickly used the principles of Gearing Up to make a super fast robotic car. After having fun analyzing how this affected motor output, sound, and traction, we did the right thing and crashed it into everything we could. Then we tested it on the incline. The builder realized right away that we had traded off too much torque for speed when the wheels would not turn on the same incline as our initial trial. We reviewed the concept of Gearing Down to gain torque at the expense of speed and began to make some design changes. 

Other builders went through some of the growing pains of figuring out how to implement gears into their drive trains. We discussed different designs and also referred to the extraordinary book “Lego Mindstorms EV3 Idea Book” by Yoshihito Isogawa. This book has invaluable examples of mechanical setups that are useful for all kinds of robotics applications. 

We plan to continue in the cycle of Brainstorming, Building Prototypes, Testing, and Analyzing Results at our next meeting, March 29, 2019.

The Challenge Instructions

Ramp Climber

Design and build a car that can climb as steep a ramp as possible.

Engineers repeatedly test their creations and use the results to make improvements to their designs. As you test your car on the ramp, pay attention to what goes wrong–does the car veer to one side, flip over, slide? Noting how the car fails may help you decide what change to try next.

Materials needed

• LEGO pieces for building a motorized one-motor or two-motor car.
• Additional LEGO beams, wheels, and gears
• Board for creating a ramp
• Protractor or app for measuring the ramp’s angle of incline

Notes for the teacher

This activity can be done using MINDSTORMS EV3 or NXT, WeDo, BOOST, or Power Functions motors and battery packs.

To construct the ramp, you will need a sturdy board approximately one-meter long. To make the angle adjustable, you can support the top of the board on a bookshelf, moving the top from shelf to shelf to adjust the angle.

Encourage the students to make only one change at a time and then evaluate it. Many of the students will be tempted to implement several of their ideas at once. Point out to them that it will be much harder to determine the effect of each modification if they have made several changes between trials.

If the students reach a dead end in trying to improve the vehicle, help them to analyze the problems they are encountering. If the wheels slip, they may want to try a different type of tires. If the car stalls in one place, they may want to gear it down to increase torque. If the car tips backward, they may want to lower its center of gravity.

Torque enters into many aspects of this lab. First, the students can increase the torque of their motors by gearing down the cars. Second, increasing the wheel size decreases the force with which the wheel pushes against the ground since the torque of the motor is more-or-less constant and the distance to the point where the force is applied increases with the radius of the wheel. Third, the cars tend to veer sideways as the ramp gets steeper. Mounting the forward wheel(s) well in front of the heavy center part of the car will tend to counteract this tendency by producing a counter-torque.

Robotics Club Happenings!

What Have We Been Doing?

During the last two week's club meetings, we have been executing the Brainstorming and Building & Testing Prototype Stages of the Design Process.

Robot Builders figured out clever ways to bring wheeled locomotion to their robots while absorbing and applying the learned knowledge about the relationships of the circumference of wheels to distance traveled. While these terms are used in Geometry, in a traditional educational setting, here we applied multiple disciplines to achieve actual movement of a robot to a specific distance (4-feet).

Multiple Disciplines

In Geometry, one may measure the diameter of a two-dimensional circle, multiply by pi (3.14….) to learn the circumference of the circle. One may then use division to see how many rotations will be needed to reach a certain distance. However, in Engineering, one will also need to select the proper width, tread, and suitability of a tire to specific terrains to accomplish that distance. During the last two club meetings, Robot Builders quickly found out that calculations cannot be our only measure of understanding, but EXPERIENCE of what can go wrong on this plane of 3-dimensional reality is just as important as the academic discipline.

Once all teams were successful in propelling their robots exactly 4-feet, we then learned about the considerations of displaying the distance on their robots. This included understanding the different functions of the motor sensors that can potentially sense a 1-degree rotation of their axles, and how we can use math functions to translate that axle movement back into the distance. We also learned how to take that dynamic data and input it through “data lines” to our “text creation” programming blocks to be stitched together with the units of measure in “inches”. And finally, builders learned how to feed all of that text into the robot’s display for everyone to see.

Here is the sample code that we focused on, to learn the functionality of each block:

The Motor Control and Display blocks are in Green. The Yellow blocks are the Motor Sensor Controls. The Red blocks are the Mathematical Algorithm block and the Text Creator block.

Rotations * Circumference = Distance

Distance divided by Time = Speed

Next week, we will be learning about the variables associated with speed. The next club meeting is March 8, 2019. We will not have a club meeting on March 15, 2019 (this is Spring Break).

- Loren Marvin, Robotics Instructor