Lily∞Bot With Circuit Playground Express and Crickit: Obstacle Avoidance

This project builds on the open-source 3d printed modular educational robot with Adafruit Crickit, Circuit Playground Express to avoid obstacles with a 3.3V sonar sensor. NoireSTEMinist.com/robots https://github.com/merl-Rose-Hulman/

This project will explain how to get obstacle avoidance working on the open-source modular 3d printed robot, Lily∞Bot, using the Circuit Playground Express, Crickit, 3.3V sonar and 2 DC motors. It will describe, building the robot, wiring the hardware and electronics and programmming the robot. Since this is graphical programming, the project is appropriate for elementary age kiddos, 1st - 4th grade. This same robot can grow with the user by changing the controller and programming language to Circuit Playground Express, Arduino Uno, Raspberry Pi Pico W, and more to come! Learn more about Lily∞Bot at NoireSTEMinist.com/robots and on Youtube at https://youtube.com/carlottaberry

robot robotics Adafruit sonar obstacle avoidance crickit circuit playground express MakeCode

Lily∞Bot base robot with upper and lower chassis, 2 caster wheels, 2 TT DC Motors, 2 TT Wheels, sonar mount, battery pack mount, and controller mount. See link for more details.

The parts list for the Lily∞Bot With Circuit Playground Express and Crickit can be found on GITHUB and on Amazon at the following links:

https://www.amazon.com/hz/wishlist/ls/16Q4OHY4E8AF3?ref_=wl_share

https://bit.ly/3Xuwe7Z

Primary components are the 3d printed parts available on GITHUB

1. Circuit Playground Express
2. Crickit
3. Sonar
4. Motors
5. Wheels

There is a new way to attach the caster wheel to raise it a little above the point of contact for the TT wheels. Please use the following images to attach the caster wheels with 4 M3 7 mm panhead or flathead screws, 4 M3 lock washers and 4 M3 washers. Lay caster wheel on top of lower chassis in the grove. Line up the holes and insert two M3 5 mm panhead screws. Add lock washer and nut to screw and tighten. Repeat for second caster wheel.

The Circuit Playground Express and Crickit can run with 4 to 5V so use either a 3AA battery pack. It can also run from the micro USB on your computer. To learn more about powering these devices visit the following links:

1. https://learn.adafruit.com/adafruit-crickit-creative-robotic-interactive-construction-kit/powering-crickit
2. https://www.adafruit.com/product/3333

Use the following instructions for adding the battery mount and battery pack.

Insert 3AA battery pack mount into the bottom of the lower chassis.

Use two 3MM M3 panhead screws to secure it to the bottom of the lower chassis.

Insert the 3AA battery pack with leads into the battery pack mount.

Use the following images to attach the Adafruit Crickit and Circuit Playground Express to the Lily∞Bot.

Use two M3 7mm panhead machine screws to attach the lower Crickit mount to the upper robot chassis.

Use four M3 5 mm panhead machine screws to attach the upper Crickit mount on top of the lower Crickit mount

Use six M3 5 mm panhead machine screws to attach the Circuit Playground Express to the top of the Adafruit Crickit.

Insert the 3.3V sonar into the sonar mount with the prongs sticking up and the arrow head ticking down as shown in the following image.

Insert sonar mount into front of upper chassis so that it locks in by turning counter clockwise. The front of the robot is closest to the words Lily∞Bot.

insert 3.3V sonar into sonar mount with pins pointing up

Drop sonar mount into front of upper chassis facing to the robot's right

Turn the mount counterclockwise until it locks in place.

Wiring for the sonar to the Crickit and Circuit Playground Express and Motor to Crickit (see Fritizing schematic for more details)

1. Sonar VCC to Crickit 3.3V Header (use male-female wire)
2. Sonar GND to Crickt GND Header (use male-female wire)
3. Sonar Trig to Crickit Pin 2 Header (use male-female wire)
4. Sonar Echo to Circuit Playground Express Pin A3 (Use alligator-male wire)
5. Connect right motor red wire to Motor 1, black wire to Motor GND
6. Connect left motor red wire to Motor 2, black wire to Motor GND

1. program Circuit Playground express with micro USB cable on https://makecode.microbit.org/
2. code available on GITHUB
3. watch the robot in action