05 Ignite the Light of Wisdom | BOSON AI Starter kit for microbit:bit

In the early stages of communication technology development, the telephone served as a tool to connect people and was once operated by rotary dialing. This rotary dialing method was widely used in the mid-20th century, and many classic telephones still use this design today. The working principle of a rotary dial telephone is based on the physical mechanism of the "rotary button." When a user rotates the dial, the pointer engages in a series of electrical contacts and disconnections, transmitting numerical signals to complete the dialing process.

In this project, we will use a rotary button and a NeurOne Module to simulate and enhance the traditional rotary dial telephone. Through programming and hardware control, we aim to implement the dialing function of the telephone.

Learning Objectives

1. Get to know and use the rotary knob module

2. Understand the difference between digital and analog signals

3. Understand the working principle of rotary dial telephones

Preparation

Learning Content

1.  Learn about the origin of the telephone

The telephone is a remote communication device that can transmit and receive sound. As early as the 18th century in Europe, the term "telephone" was already in use, referring to a simple device made by connecting cups with a string. The invention of the telephone is credited to Alexander Graham Bell. The principle of early telephones was based on the idea that spoken sound is a complex vibration in the air, which can be transferred to a solid and transmitted via electrical pulses through conductive metal. Bell applied for the patent of the telephone in March 1876.

2. Working Principle of the Telephone

Telephone communication is a technology that transmits speech by converting sound energy into electrical energy and vice versa, using electricity as the medium. The simplest form of communication between two users is to connect two telephones with a pair of wires.

When the speaker picks up the phone and speaks into the transmitter, the vocal cord vibrations stimulate air vibrations, forming sound waves.

The sound waves act on the transmitter, generating an electric current called the voice current.

The voice current travels along the wire to the receiver of the other telephone.

The receiver works in the opposite way to the transmitter—it converts the electrical current back into sound waves, which travel through the air and reach the listener's ear.

3. The Difference Between Digital and Analog Signals

Digital signals have only two values (0 and 1), which correspond to high and low voltage levels. A high level represents digital 1, and a low level represents digital 0. For example, a button module is a digital input device. Its input signal is either 0 or 1—when the button is pressed, it inputs a 1; when released, it inputs a 0.

Analog signals, on the other hand, are continuous in both time and value. Signals that represent analog quantities are called analog signals—for example, the signal input from a rotary knob is an analog signal.

Project Practice

In this project, dialing is performed using a rotary knob. First, the target phone number is learned and trained using the NeurOne Module. Once training is successful, dialing the learned number using the knob will trigger the buzzer, indicating a successful dial.

Task 1: Demonstration of Dialing and Recognition Operation

The rotary knob outputs a continuous electrical signal through its rotation. Each position on the dial corresponds to a specific signal input.

Task 2: Respond to the recognized phone number

When the system successfully recognizes the complete phone number, the buzzer will sound as a ring signal.

Task 1: Demonstration of Dialing and Recognition Operation

Hardware connection

Program Design

Function instruction

The rotary knob generates a continuous voltage signal through its rotation. The **NeurOne Module** is used to "remember" the pattern of changes in these voltage signals, enabling it to recognize and dial phone numbers.

Operation demonstration

Learning Phase

Operation: Follow the sequence shown in the diagram (1–4) and rotate the knob step by step. Each time the knob is rotated, the NeurOne Module records the rotation pattern based on the changes in voltage levels.

Completion Indicator: When the user releases the learning button, the output indicator light (white light) will turn on, signaling that the learning process is complete. At this point, the system has "memorized" the pattern and sequence of the knob rotations.

Recognition Validation: Rotate the knob according to the speed and sequence learned during the learning phase for verification. During the actual recognition process, two types of misidentification may occur:

1. Too High Precision: If you strictly follow the learned movements and the output indicator light does not turn on, it indicates that the precision is too high. The system is overly sensitive, making it difficult to recognize accurately.

2. Too Low Precision: If you rotate the knob casually and the output indicator light turns on, it indicates that the precision is too low. The system is too lenient and prone to misidentification.

Precision Adjustment

When either of these two situations occurs, you can adjust the precision of the input values and recorded values using the precision adjustment knob on the NeurOne Module.

Too High Precision: If the precision is too high, you need to rotate the blue precision adjustment knob on the NeurOne Modulecounterclockwise to reduce the sensitivity to input signals. At this point, the pointer on the knob should point to the “-” symbol, indicating that the precision is set to the lowest level.

Too Low Precision: If the precision is too low, you need to rotate the blue precision adjustment knob clockwise to increase the sensitivity to input signals. At this point, the pointer on the knob should point to the “+” symbol, indicating that the precision is set to the highest level. Note that, at the highest precision, it may be difficult to repeat the learned action perfectly due to variations in the knob's rotation speed, making recognition more challenging in this mode.

Operating Effect

After the precision adjustment is complete, the user should rotate the knob in the same sequence as during the learning phase to input the phone number. Once dialing is completed, the output indicator light will turn on, indicating that the dialing was successful.

Task 2: Respond to the recognized phone number

Hardware connection

Program Design

Function instruction

On the basis of Task 1, add sound feedback. When dialing is successful, control the buzzer to play a sound to indicate that the dialing was successful.

Flowchart Analysis

Sample program

Operating Effect

Dial the number in the same sequence as learned earlier. When the number is successfully recognized, the buzzer will provide feedback, indicating that the dialing was successful and sounding a ring.

Project Development

Can you build a model of a telephone using the materials available to you?

Materials: Cardboard box, ice cream sticks

Tools: Scissors, utility knife, double-sided tape