PJ009.5: Make MOVE Vehicle Line-Following

This project belongs to the Kitronik :MOVE Motor series projects, it based on PJ009.2: Collect MOVE vehicle sensors data. The project uses the vehicle's onboard IR light sensors to detect the black lines marked on TM016: Kitronik :MOVE mat line following and activity map, it's an application for knowledge KB017: Line Following Algorithm. This project contains 2 steps for implementation, the project can be split into 2 parts in actual teaching and learning activities. Goals:

Fun experience with Kitronik :MOVE Motor's onboard IR light sensors for line following
Engineering practice: Problem analysis, algorithm designing, solution implementation and tuning for a result
Practice with while-do looping logic
Practice using Functions to structure the program design, use function with return value
Inspire interests on robotics and programming

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Result Demo

Here is the demo of the planned results.

24w09_LP2408_programmable_vehicle_line_following_demo.mp4

Result Demo

Requirement

2 steps to implement the line-following

Effort Estimation

Prerequisite

Tools & Materials

Key Knowledge: Line Following Sensors

Key Design: Line Following Algorithm

Key Building Blocks for Programming

Implementation 1/2: Prototype with Indications, No Moving

Implementation 2/2: Add Moving and Fine-tune the Result

The Lazy Copy: 1/2: Prototype with Indications, No Moving

The Lazy Copy: 2/2: Add Moving and Fine-tune the Result

The Comparison: Bunches of Codes without Functions to Structure

Requirement

Hardware setup

Just the standard TM015: Kitronik :MOVE Motor for Micro:bit kit, remember to install the 4 batteries, TM016: Kitronik :MOVE mat line following and activity map is used for this activity.

2 steps to implement the line-following

Implementation 1/2: Prototype with Indications, No Moving
This step focuses on the algorithm designing, and verify it on the vehicle using the real sensor data, implement the evaluation of "too much to the left/right" state, indicate it on the LED matrix, the vehicle will be kept still, not moving.
Implementation 2/2: Add Moving and Fine-tune the Result
This step adds the moving functions, and assemble every piece together to make a working result, this step also includes debugging and retrying to fine-tune an expected result.

Effort Estimation

[ ] Simple: 30-60 minutes

[x] Moderate: 1-2 hours

[ ] Challenging: more than 2 hours

The estimation bases on average situation without unexpected difficult troubleshooting. It only indicates rough time needed to complete this project, but not about technical difficulty, not covering discussion and sharing time. Here is a possible breakdown:

5-8 minutes: Understand requirement and goals, collect materials
15-30 minutes: Line following sensors understanding, algorithm designing
30-45 minutes: Implementation 1/2: Prototype with Indications, No Moving
30-45 minutes: Implementation 2/2: Add Moving and Fine-tune the Result

Prerequisite

One should have prior knowledge

Micro:bit V2 board: Know what it is, better to have prior experience using them
MakeCode by Microsoft, the programming tool, better to have prior experience using it with Micro:bit
Completed PJ009.2: Collect MOVE vehicle sensors data, it's very important to have experienced with IR sensor data collection

Tools & Materials

A laoptop or tablet with internet access
1x TM015: Kitronik :MOVE Motor for Micro:bit, unboxed, or assembled
1x TM016: Kitronik :MOVE mat line following and activity map
4x Alkaline AAA batteries
1x Micro:bit V2 board , with USB cable

Key Knowledge: Line Following Sensors

Refer to TM015.1: Kitronik :MOVE Line Following Board for more details
Analog signal input to Micro:bit pin 1, 2
Read value integer
0 (darkest surface) - 1023 (lightest surface)

Key Design: Line Following Algorithm

KB017: Line Following Algorithm explains the logic. And it's very helpful to use PJ009.2: Collect MOVE Vehicle Sensors Data or PJ009.2.1: Collect MOVE Vehicle Sensors Data Using VIEW OLED Display to visualize the real time sensor data so to find out the threshold values to judge the deviation.

Too much to Left!

Left value >> Right value

Difference > 100

Too much to Right!

Left value << Right value

Difference > 100

Key Building Blocks for Programming

Add "MOVE Motor" extension

Click "Extensions"
Search by keyword "MOVE"
Click the found result
Then "MOVE Motor" blocks are available

IR light sensor (line following sensor) value

The read values are ranged as integer
0 (darkest surface) - 1023 (lightest surface).

Note:

It's the same when reading analog signal input from Micro:bit pin 1, 2.
The value is as integer, so no decimals

MOVE Motor -> Sensors-> Line Following->

While-do looping

This while-do looping is useful to help the continuous checking the ultrasonic sensor value until finding the obstacles

Loops ->

Motor control for direction adjustment

Use these blocks to control specific side's motor to to move

MOVE Motor -> Motors -> Motor Control ->

This block controls specific side's motor to stop

MOVE Motor -> Motors -> Motor Control ->

Implementation 1/2: Prototype with Indications, No Moving

In this step, the requirements are to

Build the main logic flow using functions, and
Implement "collect_latest_sensor_data."
Evaluation of vehicle driving too much in left or right side, i.e. "is_too_much_to_left/right_side."
Indicate the status on LED matrix

Snippet: The main logic

This is the main logic, as reference. There could be other solutions and the logic flow could differ a bit.

Note:

The blue block "call ..." is calling the functions that are defined separately.

Snippet: "is too much to the left/right side"?

Just follow the algorithm logic, here is the snippet

Implementation 2/2: Add Moving and Fine-tune the Result

In this step, the requirements are to

Build the main logic flow using functions, and
Implement "adjust_to_right/left_side."
Implement "driving_straight_forward."
Smoke test and fine-tune for the expected result

Snippet: "adjust to right/left side"

There are several ways to do the adjustment, here is one example to reach

Discussion & Sharing

This optional part covers further competence development, in terms of testing, troubleshooting, analysis, documentation, etc.

Open thinking

Do you have other algorithm/solution for the vehicle to
- Detect the "too much to left/right side"?
- Adjust to right/left side?
Why is the vehicle driving wagging so much? What can we do to improve the soomthness?

Troubleshooting Stories

Share with your group about

What troubles you met
How you analyze
How you get help
How you solve it
What you have learnt

Extended Learning

PJ009.2: Collect MOVE vehicle sensors data
More document and tutorials in TM015: Kitronik :MOVE Motor for Micro:bit

Further Challenges

The current solution makes the vehicle exploring all the time, never stop. Can you improve the program to let it stop after 10 times of obstacle detected?
PJ009.3: Help MOVE Vehicle Finding A Way Out