PJ009.2: Collect MOVE Vehicle Sensors Data

This project belongs to the Kitronik :MOVE Motor series projects, as a preparation for making obstacles avoidance and line following. The project uses Micro:bit serial communication (redirected to USB) to continuously send ultrasonic sensor and IR light sensor data to MakeCode to visualize and analyze the real-time environment perceptions. There is an alternative to this project PJ009.2.1: Collect MOVE Vehicle Sensors Data Using Kitronik VIEW Display. Goals:

Fun experience with Kitronik :MOVE Motor's onboard perception sensors
Experience with board-PC inter communication via serial (over USB)
Engineering practice: Data logging/collection, visualization and analysis
Knowledge preparation for obstacle detection effectiveness, and line following algorithm
Inspire interests on robotics and programming

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Result Demo

Here is the demo of the planned measurement tasks for ultrasonic sensor, and light sensors for line following.

PJ009_2_ultrasonic_sensor_data_collection_demo.mp4

PJ009_2_ir_llight_sensor_data_collection_demo.mp4

Ultrasonic Sensor (Distance Sensor)

IR Light Sensor (Line Following Sensor)

Programming: Key Building Blocks

Programming: Example Snippets

Requirement

Hardware setup

Just the standard TM015: Kitronik :MOVE Motor for Micro:bit kit, remember to install the 4 batteries, no extra need.

Distance measurement by ultrasonic sensor

Please refer to the "Tests and Analysis" section below for the test scenarios. The main purpose is to find out the effectiveness of objects detection.

Light level measurement by IR light sensor

Please refer to the "Tests and Analysis" section below for the test scenarios. The final purpose is to find out an algorithm of line following.

Effort Estimation

[x] Simple: 30-60 minutes

[ ] 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
10 minutes: Programming, download to Micro:bit, and can see data collecting ongoing
5 minutes: Focus on ultrasonic data, adjust actual distance and compare with data
10-15 minutes: Focus on IR light sensor data, place the vehicle on different surfaces, put the vehicle "in line" or "out of line", observe and analyze the data

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
Not a must, but better to have completed PJ009.1: Make MOVE vehicle driving forward

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
Some TM020: Masking Tape with different colors
1x A4 printing white paper
1x ruler (10-30 cm) to measure the physical distance

Ultrasonic Sensor (Distance Sensor)

Refer to KB016: Ultrasonic Sensor, TM019: Ultrasonic sensor HC-SR04 for more details
The distance is calculated by looking at how much the delay of hearing the reflected sound
Read value in unit cm or inch that needs to be set on start

IR Light Sensor (Line Following Sensor)

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)

Programming: Key Building Blocks

Add "MOVE Motor" extension

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

Ultrasonic sensor (distance sensor) value

Just use the block as a value of the measured distance, the unit , in cm or inch, needs to be set on start.

Note:

The value is as integer, so no decimals, which means the resolution of distance value is a full 1 cm/inch

MOVE Motor -> Sensors-> Ultrasonic->

Remember to set unit on start

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->

Send data from Micro:bit to PC

Use this to send the collected data to PC/laptop, for continuous visualization and analysis.

Note:

The technology behind is "serial communication", but redirected to USB.
USB cable must be kept connected!

Advanced-> Serial ->

Visualize real time data in PC

Programming: Example Snippets

Below snippets are served to inspire and help starting, but not ready-made solution for the actual tasks in this project.

Snippet: Collect ultrasonic sensor data

This snippet sends the real time distance detection data to PC

Snippet: Collect IR light sensor data

This snippet collects left and right light sensor data, and the difference value

Tests and Analysis

Ultrasonic sensor

Test 1:

Place the vehicle towards a good blockage (e.g. a box with flat surface, large and high enough), in 3 different distances (near, mid, far), measure the physical distance, compare with the data from ultrasonic

Real distance
Sensor value
Difference

Are you satisfied with the data accuracy vs reality?

Test 2:

Try an irregular shape object, like a coffee mug, test again, find out how accurate the measurement data is

Real distance
Difference placement of the object (height, angle, etc.)
Sensor value
Difference

How accurate is it for this object now?

Test 3:

Try a random small irregular object, like a marker pen, test again, find out how accurate the measurement data is

Real distance
Difference placement of the object (height, angle, etc.)
Sensor value
Difference

Can the sensor detect this small object? How accurate about the data for distance vs reality? What needs to be minded for this kind of objects detection by ultrasonic sensor?

IR light sensors

Test 1:

Put the vehicle on top of different surfaces (different color or materials), try at least 3 options, observe the real time data, find out the differences.

White paper
Black surface, e.g. the laptop
Colored surface, table top, or a book, etc.

What kind of surface gives the highest sensor value? The lowest sensor value?

Test 2:

Test on different tapes, find out the sensor values difference on top of the tapes and on the white paper.

Black tape
Blue tape
Yellow-white tape

Which kind of tape gives the most differences comparing to white paper? Which tape is more suitable to mark a line following map?

Test 3:

Test on the standard TM016: Kitronik :MOVE mat line following and activity map, place the vehicle on top of the line, place the vehicle (accurately it's the sensor board).

The Left/Right is meant from the vehicle's point of view in forward direction.

In the middle of the line
Left deviated from the line
Right deviated from the line

What is the pattern from the real time data for above situations?

Discussion & Sharing

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

Ultrasonic sensor discussion

Can you sort out an answer for those questions for ultrasonic sensor?

How does the ultrasonic sensor detect the distance?
What could affect the accuracy of distance measurement?
How to ensure a better measurement quality?
What could be missed from the perception of ultrasonic sensor?

IR light sensor discussion

Based on the analysis of the left/right/diff data from the sensors when the vehicle is in the middle of the line, left deviated, right deviated from the line, can you figure out an algorithm for line following?

Note: The Left/Right is meant from the vehicle's point of view in forward direction.