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Robot Club - Generic Features, Sensors & Hardware Resources
Overview, Introduction & Prerequisites:
This is a repository of Features, Sensors & Hardware that is used with the Robots & Rovers... Mostly
Prerequisites:
No explicit prerequisite course work, Electronics, Logic, or coding knowledge is required. Come as you are. 🧠
Topics:
Random Robot / Rovers Hardware
iRobot Motors
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- Unit: Robot Club
- Neato / Roomba Vacuum Type Rovers
- This is a LEARNING Activity : Lesson / Lab
- Last Revised: Oct 02, 2026 - Authored: Sept 13, 2025
- Original Author: Jim Burnham - TopClown@STEAMClown.org
- Content License: Distributed as Open Source. See Rights & Usage
Note: TEACHERS!!!! If you are going to use any of these lessons or labs, please let me know. I would really like to understand how you are using this material. I want to know what works, what does not work, what would you like me to add, and how I can make it better. If you changed something, let me know, because it's probably a good idea and you should share it with me, so I can add it and share with everyone else.
This Module or lesson is how I teach in my class. Many of the lessons might be specific to my class, but you could probably adjust them for your class. I'll try to make them a neutral as I can, so they can be used in any Mathematics, Physics, Computer Science, or any other Engineering / Technology class. Let me know how I can make that better. I'll try to keep this unit current and relevant. Please let me know if any resource links are broken or not accessible.
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Overview and Introduction:
Overview and Introduction:
Author: Jim Burnham - TopClown@STEAMClown.org. License: Distributed as Open Source.
Sponsor Shout Out
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Prerequisites:
Prerequisites:
No explicit prerequisite course work or coding knowledge is required, but students are expected to have a good understanding of basic computer principles.
Caution & Safety Considerations:
Caution & Safety Considerations:
Primer: "Aaron, I can imagine no way in which this thing could be considered anywhere remotely close to safe. All I know is I spent six hours in there and I'm still alive... You still want to do it?"
As with any activity, please make sure you are using appropriate safety equipment. If you are coding, writing, reading, or working a lab, make sure you stand up and stretch every hour or so, Please consider any safety issues connecting to a Raspberry Pi, Arduino, computers and other electronic equipment.
Essential Questions:
Essential Questions:
What information can you transwmit & recenve on a Rover or Robot?
Stuff My Rovers Should Have On Them
Stuff My Rovers Should Have On Them
Safety Topics
Safety Topics
Emergency-Stop
Addition Safety Topics:
Layered E-stop - Fail-safe NC latching relay + motor-driver enable pin
RF dead-man switch - Untethered outdoor operation (walk along pull cord), Remote "Kill /Deadperson" button built into controllers
Standards awareness - ANSI/RIA R15.08, ISO 3691-4, ISO 13849-1, UL 3100
The biggest gaps for the big outdoor rover, in priority order:
A link-loss failsafe. The rover should stop automatically if the control link drops. You've designed a layered E-stop and a dead-man switch, but a watchdog on the radio link is a separate protection.
Health monitoring. Track battery voltage and current, current on each motor, and temperatures on the hub motors and controllers. Hub motors working through grass get hot, and current spikes are your best stall and stuck-in-mud indicator.
Sensors that work in sunlight. Ultrasonic and cheap IR ToF sensors that work indoors struggle outdoors in sunlight and grass. Plan on an outdoor-rated LiDAR plus downward-facing "cliff" sensors to catch ditches and holes.
Sensor fusion. Combine RTK GPS, the IMU, wheel and steering encoders and optical flow in an EKF (ROS 2 robot_localization) instead of trusting any single source.
Tilt cutoff, geofence and stack light. These are cheap and important once the rover is heavy and moving fast near people.
Feature Topics
Feature Topics
Stuff
Addition Feature Topics:
Easy way to switch from RC control to Autonomous / Semi Autonomous
Downward ToF "cliff" sensors - Detect ditches, curbs and holes ahead of the wheels
Long-range telemetry (LoRa or a SiK-style radio) - Control and status that reach beyond Wi-Fi range
Auto-docking + charging station - Long-term autonomy
FPV / camera video link - Remote driving and inspection. pass video data to base statuin. not processed on the rover, but set to remote location (like SkillsUSA US&R)
GPS (Low cost)
RTK GPS + dual-antenna heading - Centimeter positions plus heading that doesn't depend on a magnetometer
Outdoor-rated 2D or 3D LiDAR - Ultrasonic and cheap IR ToF struggle in sunlight and grass. A sunlight-tolerant LiDAR handles obstacles and mapping
Downward ToF "cliff" sensors - Detect ditches, curbs and holes ahead of the wheels
Stereo / depth camera - Terrain and obstacle depth; check that it is rated for sunlight
Geofence - Software boundary using GPS. Stop or return if the rover leaves the field
Link-loss failsafe - Rover stops automatically if the control or telemetry link drops for more than about 0.5–1 s. Separate from the dead-man switch.
Battery monitoring - (INA226 / INA228 current and voltage, plus a proper BMS) Range estimation, low-voltage cutoff, speed compensation, and lithium safety (UL 3100 concerns)
Per-motor current sensing - Stall detection, wheel slip, overload protection, stuck-in-mud alerts
Temperature sensors on hub motors, motor controllers and battery - Hub motors on grass work hard; thermal derating prevents damage
Tilt / rollover cutoff from the IMU - Stop motors past a safe pitch or roll angle
Physical bumpers or contact switches Last-resort collision detection that works when the cameras don't
Stack light + buzzer Shows armed / autonomous / fault states to people nearby
Communication Location Features:
GPS 2–5 m typical Outdoor baseline
RTK GPS (u-blox ZED-F9P class) ~2 cm Recommended for the big rover
DIY differential GPS from fixed APRS beacons Partial correction of common GPS error Student experiment
APRS trackers (144.390 MHz) Map tracking of rover and field beacons Legal under automatic control as data emission
Fox-hunt beacons (144.275–144.300 MHz) Radio direction-finding targets Automatic-control beacon segment
RDF bearing triangulation Position from bearings to known beacons Yagi or Doppler DF on the rover
RSSI trilateration Rough distance from signal strength Noisy; teaching example
LoRa SX1280 time-of-flight ranging Meter-level, hundreds of meters License-free, 3 anchors + rover
LoRa sx1280 Amazon with links to wiki and other docs
UWB (Qorvo DW3000) ~10 cm Borderline range at 100–200 m outdoors
915 MHz LoRa / Meshtastic (Part 15) License-free student beacons and telemetry Classroom-friendly
Vision Features:
USB UVC cameras - (any USB camera - Seeed X10 1080p) Teleop, data collection, vision - Pi 5 rover, LeKiwi
Depth camera (Orbbec Gemini 2 / 305) 3D perception, obstacle depth LeKiwi options, robot arm discussion
Thermal (FLIR Lepton 3.5, MLX90640) Heat detection, motor/servo heat monitoring Robot arm discussion
NoIR camera + IR illuminator Low-light vision Robot arm discussion
OpenCV, YOLO, MediaPipe, ArUco markers Detection, tracking, fiducial navigation Pi 5 rover toolkit
Visual odometry Position from camera motion Distance-measurement discussion
Color Blob Detection
Color (Light) Detection - Is this different than ambient reflected color, like seeing a orange cone vs a RGB LED light?
Ranging, Obstacle and Line Sensors
Ultrasonic (HC-SR04) Distance, obstacle avoidance Arduino curriculum Module 8
IR line sensor / array Line following Arduino curriculum
ToF / LiDAR to a wall Precise reference distance Distance-measurement discussion
LiDAR (2D) SLAM, mapping Pi 5 rover toolkit
Motion Sensing and Odometry
Wheel encoders (quadrature and single-line) Distance, speed, turn angle Viam rovers use single-line encoders; curriculum Module 9
Encoder-free open-loop trim Rough straight driving First step for motors without encoders
Gyro heading hold (IMU + PID) Straight driving without encoders MPU-6050, BNO055, BNO085
Accelerometer (ADXL345 on Viam Rev 1) Motion, tilt, bumps Double integration drifts with t²
Zero-Velocity Updates (ZUPT) Resets velocity drift when stopped Drive-stop-drive pattern
Time × calibrated speed Rough distance Scale for battery voltage
Accelerometer vibration FFT Wheel RPM estimate Advanced, surface-dependent
Stall / stuck detection Motors commanded but no motion IMU-based; valuable without encoders
Collision detection Acceleration spike IMU-based
Magnetometer / compass Absolute heading Keep away from motors and steel
Back-EMF speed sensing Motor speed without encoders Fiddly; good advanced lesson
Optical flow (PMW3901) True ground motion, catches slip Best low-cost encoder alternative
Sensor Topics
Sensor Topics
Sensors
Ultrasonic - Arduino - with functions to check distance/objects
Set of functions
method to pass to a Raspberry Pi (serial or i2c)
IMU - Data and status loging / passing to Arduino/Raspberry Pi
Addition Sensor Topics:
Black-box data logger - Logs commands, sensor data and faults for debugging and student analysis
Telemetry - Live dashboard (MQTT + Grafana or a web UI) - Battery, temperatures, GPS track, faults
Fiducial markers at the field base (ArUco / AprilTag) - Precise docking with the camera
Environmental (temp, humidity, wind, pressure, weather. etc) - A mission payload that turns the rover into a field science platform
Thermal camera on the rover - Spot hot motors, find people and animals, night detection
Ambient light sensor + headlights - Dusk operation and better camera exposure
Solar Compass - analog mux project.
Hardware Topics
Hardware Topics
Hardware Structures
Addition Hardware Structures Topics:
Payload mount with standard power and data ports - Lets student teams swap in their own sensor modules. Define a standard connection point hardware standard, with power and data ports.
Motors & Drive Topics
Motors & Drive Topics
Drive Types
Drive Types
Omni is a poor fit for grass.
Mecanum (4 wheels, with a pivoting axle or suspension) works, but expect weak strafing.
Swerve if omnidirectional performance outdoors is the main goal.
Skid steer with the plain hub tires if you mostly just need to go places and turn in place. <-- Most Differential Drive rovers are "Skid" Drive.
Drive Systems and Mobility
Differential drive (2 wheels + caster) Base platform for the curriculum and Viam rovers Arduino rover curriculum, Viam rovers
Omni wheels, 3-wheel Kiwi drive Holonomic; 120° layout; good for kinematics math Omni vs. mecanum discussion, LeKiwi
Mecanum wheels, 4-wheel X layout Holonomic; weak strafing on grass; needs all 4 wheels in contact Big rover wheel choice
Swerve drive Steerable modules; best holonomic option on grass; wire-twist challenge with hub motors Big rover
Skid steer Simple, robust outdoor fallback Big rover
Onewheel-style hub motors, ~40 cm wheels Planned drive for the big grass/dirt rover Big rover
Pivoting (rocker) axle / suspension Keeps 4 wheels on uneven ground Big rover
Feetech STS3215 bus servos as drive motors Serial bus, 12-bit magnetic encoder, IDs 7/8/9 on LeKiwi LeKiwi
iRobot Motor & The PCB Signal Pinout
iRobot Motor & The PCB Signal Pinout
Pro-Tip: When you open the iRobot vacuum, you can desolder the motor female connector fairly easily. Then you can use it later to solder wire to, and then still slip on the PCB.
A = Motor A - These A/B pins would connect to your motor controller Motor pins, and you would control them with your In1, In2, EnB on a standard motor controller. The motor voltage can be 12v... though I would run them at around 9v
B = Motor B
5V = 5v from some 5v supply. Most of our Rover builds will have a Battery-2-5volt DC/DC regulator.
ENC = HallEfect sensor (low) for Encoder value, The hall effect actually switch fro GND to "floating" so it is save to connect to the 3.3 Raspberry Pi pins.
WD(not) = Switch (Active Low) Switch to
GND = Ground
See a good YouTube - Hacking Robot Vacuum (Roomba) Wheel and Motor Modules for Raspberry Pi or Arduino Robot Project
Hall Effect Sensor:
Question: For a hall effect sensor, what does it mean when doc say it switched between GND and "floating" so it's safe to connect to a 5 Arduino or a 3,3 Raspberry Pi input?
Answer: What they’re describing is an open-collector (or open-drain) output, and the wording “switches between GND and floating” is the key clue.
What “GND ↔ floating” actually means
What “GND ↔ floating” actually means
The Hall effect sensor does NOT drive the output high. Instead, it behaves like this:
Active state: internally connects the output pin to GND (0V)
Inactive state: disconnects the output pin → it becomes floating (high impedance)
So the sensor only ever pulls the line LOW, never pushes it HIGH.
Why that’s safe for both 5V Arduino and 3.3V Raspberry Pi
Why that’s safe for both 5V Arduino and 3.3V Raspberry Pi
Because you control the HIGH voltage, not the sensor.
You add a pull-up resistor to whatever voltage your system uses:
On an Arduino Uno → pull-up to 5V
On a Raspberry Pi 4 → pull-up to 3.3V
The sensor just pulls the line down to ground when triggered.
When it’s “floating,” the pull-up resistor brings the line up to your logic voltage.
👉 That means:
The sensor never outputs 5V or 3.3V directly
So it can’t over-voltage your Pi’s GPIO (which is critical—Pi pins are NOT 5V tolerant)
Simple wiring concept
Simple wiring concept
Vcc (sensor power)
|
[Hall Sensor] ENC pin
|
+-----> GPIO input
|
[Pull-up resistor]
|
+3.3V (Pi) OR +5V (Arduino)
Why this is commonly used
Why this is commonly used
This design is popular because it enables:
Level shifting for free (same sensor works at different voltages)
Multiple devices on one line (wired-AND behavior)
Safer interfacing with mixed-voltage systems
One thing to watch
One thing to watch
Don’t leave it truly floating:
You must use a pull-up resistor (typically 4.7kΩ–10kΩ), OR
Enable the microcontroller’s internal pull-up
Otherwise, your input will read random noise.
Bottom line
Bottom line
“Switches between GND and floating” =
➡️ “I only pull LOW; you decide what HIGH means”
That’s exactly why it works cleanly with both 5V and 3.3V systems without extra level shifting.
Reference, Attribution & Resources:
Reference, Attribution & Resources:
License - "Be A Hero"... Distribute Your Content As Open Source... That Is What I'm Doing...
License - "Be A Hero"... Distribute Your Content As Open Source... That Is What I'm Doing...
The content on this site may have been pulled from other open source sites, but typically the interpretation and presentation is primarily the Intellectual Property of Jim Burnham, - TopClown@STEAMClown.org at www.steamclown.org and the Student curriculum can be found under the specific Mechatronics Engineering Units section of this web site.
If you do use my material, and make changes, I would appreciate getting a copy... because if you are making changes, it means that you think there is a better way to teach this… and I would really appreciate understanding that. Please send me feedback on my Questions or Feedback form. Please don’t hesitate to ask questions or comment.
You also should keep and include my STEAM Clown Logo and Copyright in any derivative works you create. I would appreciate if you would include one of these images found on my Steam Clown License page and link it to www.steamclown.org
If you do use my material, and make changes, I would appreciate getting a copy... because if you are making changes, it means that you think there is a better way to teach this… and I would really appreciate understanding that. Please send me feedback on my Questions or Feedback form. Please don’t hesitate to ask questions or comment.
You also should keep and include my STEAM Clown Logo and Copyright in any derivative works you create. I would appreciate if you would include one of these images found on my Steam Clown License page and link it to www.steamclown.org
Teachers - Unit, Module and Lesson Plans
Teachers - Unit, Module and Lesson Plans
If you are a teacher and want to connect and teach this Lesson or Module, discuss how I teach it, give me feedback, please contact me at TopClown@STEAMClown.org
To access this Lesson Plan and the Teacher collaboration area, you will have needed to connect with me so I can Share the content with you. Please go to the Teachers & Partner Page, check out my Licensing and fill out my Collaboration and Curriculum Request Form. I'll review and then grant you access to the requested areas and lesson plans if they exist.
If you have questions or feedback on how I can make a presentation, lesson, lab better please give use my Feedback Form.
Standards Alignments & Objectives:
Standards Alignments & Objectives:
I’ll work on getting these in, but it’s the last thing I want to work on :-) When I have them updated, I’ll move to the top of the Lesson Plan.
NGSS: <list standard numbers>
California CTE Standards: <list standard numbers>
Related Instructional Objectives (SWBAT): <list standard numbers>
CCSS: nnn, RSIT: nnn, RLST: nnn, WS: nnn, WHSST: nnn, A-CED: nnn, ETS: nnn <list standard numbers>
Main Standard:
Priority standards:
National Standards:
Resource Attribution:
Sites Referenced or Summarized:
Resource Attribution:
Sites Referenced or Summarized:
Reference Text Book - Basic College Mathematics with Early Integers 4th edition - Elayn Martin-Gay - University of New Orleans - Pearson
Reference Sites -
Images:
Images:
https://imgbin.com/png/ZJtzkYZZ/under-construction-png
Random Stuff To Sort
Random Stuff To Sort
Resource Key:
Resource Key:
<Unit> - <Module Name> - Lessons - Daily/Weekly Lesson Plan
<Unit> - <Module Name> - Lessons - Daily/Weekly Lesson Plan
Key: 📰 Slides / Audio 🎧 / 📽️▶️ Video/YouTube / 🎧▶️📽️ Audio/Video / ✨ Resources / 🖼️ Tutorial / 📖 Reading Activity / 📝 Writing Activity / 📖 📝 Reading/Writing / 📟 Coding / 🛠️ LAB Activity / 🚀 Quiz / 🔎 Review / ✔️ Mastery Check / ✍️ Sign Up /🍕 Extra Credit / 🕸️ Web Links / 👩🏽🎓🧑🏽🎓🧑🏿🎓👩🏫 Class / 🏵️📜📃 Certificate / 🗂️ 📈 Collecting Survey Data
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This is an ⚓ Establishing Assignment (Minimum Standard) - "Everyone Do" Assignment
This is an ⛏️ Developing (Digging Deeper) - "Everyone Should Do, To Stretch" Assignment
This is an 💎 Aspiring (Putting It Together) - "When you have done the ⚓ Establishing and⛏️ Developing" Assignment
🚀 Formative Quiz - 🔎 Review
🚀 Quiz -🔀 Mastery Path
🚀 Summative Quiz -✔️ Skills Mastery Check
Quiz - verify that they are all listed as a "Formative", "Mastery Path", or "Summative"
🚀 Formative Quiz - These are quizzes that the students can take a few times. I have them either set for unlimited times, or 3-5 times, where the final score is their average. The idea is that these Formative Quizzes are designed for students to learn and master a skill. while I want them to ger 100%, and when it's set to unlimited tries, the student should get 100% eventually. When the quiz is set to 3-5 tries with an average, then they should be prepared and should take the quiz seriously. I set the quiz to not show the right answer, but I do let them see their wrong answer. I also put the explanation of the right and wrong answer in the right and wrong answer prompt for each question. That way they can see why they got the answer wrong and learn from that experience.
8.1.0.3.2.4 - Python - Ch 3 - Functions - Quiz #2 -Built-In Functions - 🚀 Formative Quiz
🚀 Quiz -🔀 Mastery Path - These Mastery path quizzes are to be presented after the student has had a chance to do some labs and some Formative quizzes. The goal is to let students have 2 chances to take this quiz, and take the average of the 2 attempts. Based on the average, they will be presented with a Canvas Mastery Path, where they will have an option for take additional quiz and assignments to help with remediation. This will get them ready to take the Summative Quizzes.
8.1.0.3.3.1 - Python - Ch 3 - Functions - Mastery Quiz #1 - 🚀 Quiz -🔀 Mastery Path
🚀 Summative Quiz -✔️ Skills Mastery Check - These Mastery path quizzes are to be presented after the student has had a chance to do some labs and some Formative quizzes. The goal is to let students have 2 chances to take this quiz, and take the average of the 2 attempts. That will be their final module/subject topic grade.
8.1.0.3.3.1 - Python - Ch 3 - Functions - Skills Mastery Check Quiz #1 - 🚀 Summative Quiz -✔️ Skills Mastery Check
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