Red-Light Green-Light Robot

Win Scenario

The opportunity we set out to execute through our project, the Red-Light Green-Light Robot, was to create a form of entertainment for children in busy homes. After carefully considering our options, we decided to create a small outdoor robot that will play Red-Light Green-Light with you. This is because we wanted a toy that a child could safely engage themselves with, allowing their parents more time to complete household tasks and maybe even relax. Keeping in mind that children were our target audience, we built our toy out of Lego Mindstorms. This toy conveys different colors and sounds through the implementation of coding and sensors. There are four colors, green means go, red indicates stop, yellow signifies you won, and purple represents you lost. For the sensor aspect of the project, we included a button and IR sensor (Infrared Sensor). If the button is pressed on a green light, the robot turns yellow and makes a cheering noise, and if pressed on a red light, it displays purple and plays sad trumpets. Likewise, if caught moving during a red light, the robot would respond the same as if the button was pushed on red light. All of which can be viewed from the links below:

After meeting with teammates and professors on April 5th, 2022, we discussed project goals and requirements, and were given examples of previous works that the instructors thought may be helpful. After the meeting, the following points were deemed the most important implementations of the final product:

The main frame is sturdy and has areas for all sensor attachments
The motors are functional and attached to the frame
The motors allow 180 degrees of pivoting back and forth
The IR sensor is attached and can detect motion
The LED strip is attached and can change colors accessibly
The main game code is written and functional
IR data can be displayed
Data is processed to determine if motion occurs during a red light state

Moreover, even though the robot was designed for children of busy households, it can be used by anyone who has access to a large open area. This toy will get children outside and engaging in physical activity, all the while allowing stay-at-home parents more quality time to decompress and complete daily tasks.

Game Play Scenario

Win Scenario

Lose Scenario

Game Play Cycle

Win Scenario

The Prototyping Process

P\Prototype 1

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Prototype one consisted of two sketches. One drawing was the original design from the project pitches, and the second was the revised version. The initial concept for the Red-Light Green-Light Robot was a ladybug. However, after some additional research, we discovered that green ladybugs did not exist in the wild, so the team decided to change the animal.

This time around, we took caution to pick animals that could be both red and green. Since a chameleon can change colors depending on its surroundings, it was selected to replace the ladybug. To accommodate this change, our final design concept consisted of a chameleon hanging onto a branch. Doing so creates space for the electronic components will be attached to a base plate and covered with decorative rocks. During this phase, the base, chameleon, and rocks were to be 3D printed and connected to a LEGO frame. Additionally, we planned to attach our sensors to the frame underneath the 3D printed components.

Prototype 2

For prototype two, our group developed the preliminary 3D models for the log cover and chameleon. In addition to this, we constructed the internal skeleton for the wiring and sensors. Once the frame was complete, we attached the Lego Mindstorms EV3 brick, LED strip, IR sensor, button, and motor. From there, we developed the tester code. This code essentially was created to test our ability to change colors, rotate the motor, and display proximity readings from the IR sensor. Once these were able to work separately, we compiled and arranged them into one large code, which included for/while loops, and if/break statements.

Green Light

3D Models

Red Light

Loss Scenario

Progression of Attachable Component

For the final product, instead of using the chameleon as shown in prototype two, we decided to find a pre-existing one that was more inviting. The original model was a bit scary, and we were running low on time to model another one from scratch. After finding a model which would fit this role, we printed it in white PLA. The chameleon was then coated in multiple layers of acrylic paint, starting with the log. Each color was hand-mixed, spread with a round tip paintbrush for the outlines, and filled with a flat brush. Once dry, a layer of light green paint was applied to the chameleon's body. Again, letting it dry, the third and final step was to add fine details with the round tip brush to give the chameleon character.

Step 1

Step 2

Step 3

Final Product Assemblage

Overall, the Red-Light Green-Light Robot have turned out to be almost exactly what we had planned for. The IR sensor is able to detect motion, and change colors according to our code. The chameleon pivots frontward 180 degrees on red and backwards 180 degrees on green. Additionally, we were also able to construct an internal skeleton which supports the wiring and LED's. Yet there are a few aspect from the original design that we were unable to accomplish. Our project deviates from what was established in our proposal because of the range at which the IR sensor can detect motion. The LEGO Mindstorms EV3 IR sensor can only discern motion for up to 100 cm, approximately 2 feet, which was an aspect we were unaware of when deciding to use LEGO. Due to this, our game cannot be played without someone distinguishing movement when used outside of the range. If you are inside the IR sensors range, the game works as initially discussed. Further, instead of a 3D printed log, we made a plywood box as the base and formed a tree limb out of molded thermoplastic pellets. We overlaid the branch with felt in the pattern of tree bark. Nonetheless, the toy meets the stakeholder needs we set out to fulfil, its easy to operate, is sturdy, easy to move and store, is engaging, includes Wi-Fi connecting capabilities via Bluetooth, has two sensors with input and output capabilities, and is safe to be used by children.

Take Aways

The most impactful thing I learned through developing the Red-Light Green-Light Robot was working through challenging moments. There were multiple setbacks when it came to completing this project. Either our code wouldn't work, the 3D models were not ready, or people were not showing up to help. No matter what the excuse, at the end of the day, there is a deadline, and something needs to get something finished, even if your part is technically complete. I put in numerous hours outside of class to ensure our group had something functional to present. The robot may not have turned out exactly as planned, but it was completed on time.