WALT: definition and decomposition of complex problems in terms of functional and non-functional requirements

Transcription

1 Item 12: Burglar Alarmed Monday, 15 October :31 PM BURGLAR ALARMED EXPLORE WALT: definition and decomposition of complex problems in terms of functional and non-functional requirements WILF - Defined how each component works by identifying or describing their qualities. - Identified where and why component are connected into the GPIO - Described how the circuit works and the relationships between components. Processes and production skills Investigating and defining A B C The student work has the following characteristics: The student work has the following characteristics: The student work has the following characteristics: purposeful definition and decomposition of complex problems in terms of functional and non-functional requirements - Defined how all components works by identifying or describing their qualities. - Identified why and where all of the components are connected into the GPIO - Described how the whole circuit works, with both text and images. effective definition and decomposition of complex problems in terms of functional and non-functional requirements - Defined how most components works by identifying or describing their qualities. - Identified why and where most of the components are connected into the GPIO - Described how the circuit works, with both text and images. definition and decomposition of complex problems in terms of functional and non-functional requirements - Defined how some components works by identifying or describing their qualities. - Identified why and where some of the components are connected into the GPIO - Described how the circuit works. Difficulty: moderate Estimated Effort: 70 Mins Value: 10% Components List: Arduino Board USB Cable Piezo Buzzer Ultrasonic Sensor Physical Computing and Embedded Sytems Page 1

2 Ultrasonic Sensor This sensor bounces a sound wave of a frequency (that cannot be heard by the human ear) off a surface and measures the amount of time it takes for the sound to return to the sensor. Here s what happens: The transmitter (trig pin) sends a signal: a high-frequency sound. When the signal finds an object, it is reflected and the transmitter (echo pin) receives it. The time between the transmission and reception of the signal allows us to know the distance to an object. This is possible because we know the sound s velocity in the air. From < An ultrasonic sensor s accuracy and range mean it can measure distances between 2 and 300 cm. However, because the sound wave needs to be reflected back to the sensor, the sensor must be angled less than 45 degrees away from the direction of travel. Connecting the Ultrasonic Sensor To connect the sensor, attach the Vcc lead to the 5V pin and the Gnd lead to any GND pin. The Trig and Echo can be connected to any GPIO pin. Physical Computing and Embedded Sytems Page 2

3 Using the Ultrasonic Sensor To Measure Distance The ultrasonic sensor takes measurements only when requested to do so. To take a measurement, we send a very short HIGH signal of 5 microseconds (ms) to the SIG pin. After a moment, the sensor should return a HIGH signal whose length is the period of time the ultrasonic sound takes to travel from and to the sensor; this value should be halved to determine the actual distance between the sensor and the object. We need to use the same digital pin for output and input, and two new functions: delaymicroseconds(ms) Pauses the Arduino sketch in microseconds (ms) pulseduration(pin, HIGH) Measures the length of a HIGH pulse on digital pin pin and returns the time in microseconds After we have the duration of the incoming pulse, we convert it to centimeters by dividing it by (because the speed of sound is 340 meters per second, or 34 cm per millisecond). To simplify using the sensor, we use the function getdistance() More Resources: How an Arduino Ultrasonic Sensor Works Ultrasonic HC-SR04 Range Sensor Pins used: GND, GND, 5V, 11, 6, 7, The buzzer will work from outputting a HIGH(5V) or on and LOW (0V) or off signal through pin 11. The Ultrasonic Sensor is powered via the GND and the 5V pins A Trigger OUTPUT signal is sent to the Ultrasonic Sensor via pin 7 An Echo INPUT return signal is sent to the board via pin 6 The Circuit: INSTRUCTIONS 1. Connect as shown in the Fritzing (circuit) diagram above. Take a photo for your portfolio, or set up a virtual circuit in tinkercad and take a screenshot. 2. Answer these questions: Physical Computing and Embedded Sytems Page 3

4 Portfolio Task Questions for EXPLORE 1. Define how each of the components work? Identify each component and describe how they work with text and images. 2. Identify what and where components are plugged into the GPIO. Why there? 3. Describe How the circuit works? Tell the story. Include a picture. [ use ] DEVELOP WALT: design and evaluation of user experiences and algorithms WILF Design - interpret existing code: > Analyse to identify where input, output, processing and storage occurs in the code. > translated code into pseudocode - Plan to modify parts of the code to make it work differently or more effectively Evaluation - Recommended ways to use the technology differently. Processes and production skills Generating and designing - producing and implementing A B C The student work has the following characteristics: The student work has the following characteristics: The student work has the following characteristics: purposeful design and evaluation of user experiences and algorithms - identified where all input, output, processing and storage occurs in the code. - translated all code into pseudocode - Plan to modify several parts of the code to make it work differently - Recommended ways to use the technology differently. effective design and evaluation of user experiences and algorithms - identified where most input, output, processing and storage occurs in the code. - translated most code into pseudocode - Plan to modify some parts of the code to make it work differently - Recommended some ways to use the technology differently. design and evaluation of user experiences and algorithms - identified where some input, output, processing and storage occurs in the code. - translated some code into pseudocode - Plan to modify some parts of the code to make it work differently - Recommended a way to use the technology differently. Algorithms: Sequence, selection Code structure, values and functions: int [Data Types] To store a value in code, we use variables. There are many kinds of values or types of data that we may want to store. Integers are your primary data-type for number storage From < If else [Control Structure] The if statement checks for a condition and executes the proceeding statement or set of statements if the condition is 'true'. Physical Computing and Embedded Sytems Page 4

5 if (condition) { //statement(s) condition: a boolean expression i.e., can be true or false The statements being evaluated inside the parentheses require the use of one or more operators shown below. Comparison Operators: x == y (x is equal to y) x!= y (x is not equal to y) x < y (x is less than y) x > y (x is greater than y) x <= y (x is less than or equal to y) x >= y (x is greater than or equal to y) From < digitalwrite() [Digital I/O] Write a HIGH or a LOW value to a digital pin. If the pin has been configured as an OUTPUT with pinmode(), its voltage will be set to the corresponding value: 5V for HIGH, 0V (ground) for LOW. digitalwrite(pin, value) pin: the pin number value: HIGH or LOW From < pinmode() [Digital I/O] Configures the specified pin to behave either as an input or an output pinmode(pin, mode) pin: the number of the pin whose mode you wish to set mode: INPUT, OUTPUT, or INPUT_PULLUP. (see the (digital pins) page for a more complete description of the functionality.) From < delay() [Time] Pauses the program for the amount of time (in milliseconds) specified as parameter. (There are 1000 milliseconds in a second.) delay(ms) ms: the number of milliseconds to pause (unsigned long) From < delaymicroseconds() [Time] Physical Computing and Embedded Sytems Page 5

6 Pauses the program for the amount of time (in microseconds) specified as parameter. There are a thousand microseconds in a millisecond, and a million microseconds in a second. Currently, the largest value that will produce an accurate delay is This could change in future Arduino releases. For delays longer than a few thousand microseconds, you should use delay() instead. delaymicroseconds(us) us: the number of microseconds to pause (unsigned int) From < pulsein() [Advanced I/O] Reads a pulse (either HIGH or LOW) on a pin. For example, if value is HIGH, pulsein() waits for the pin to go from LOWto HIGH, starts timing, then waits for the pin to go LOW and stops timing. Returns the length of the pulse in microseconds or gives up and returns 0 if no complete pulse was received within the timeout. The timing of this function has been determined empirically and will probably show errors in longer pulses. Works on pulses from 10 microseconds to 3 minutes in length. pulsein(pin, value) pulsein(pin, value, timeout) pin: the number of the pin on which you want to read the pulse. (int) value: type of pulse to read: either HIGH or LOW. (int) timeout (optional): the number of microseconds to wait for the pulse to start; default is one second (unsigned long) Returns the length of the pulse (in microseconds) or 0 if no pulse started before the timeout (unsigned long) From < Serial.begin() Sets the data rate in bits per second (baud) for serial data transmission. For communicating with the computer, use one of these rates: 300, 600, 1200, 2400, 4800, 9600, 14400, 19200, 28800, 38400, 57600, or You can, however, specify other rates - for example, to communicate over pins 0 and 1 with a component that requires a particular baud rate. An optional second argument configures the data, parity, and stop bits. The default is 8 data bits, no parity, one stop bit. Serial.begin(speed) Serial.begin(speed, config) speed: in bits per second (baud) - long config: sets data, parity, and stop bits. Valid values are : Physical Computing and Embedded Sytems Page 6

7 From < Serial.println() Prints data to the serial port as human-readable ASCII text followed by a carriage return character (ASCII 13, or '\r') and a newline character (ASCII 10, or '\n'). This command takes the same forms as Serial.print(). Serial.println(val) Serial.println(val, format) val: the value to print - any data type format: specifies the number base (for integral data types) or number of decimal places (for floating point types) Returns size_t (long): println() returns the number of bytes written, though reading that number is optional From < tone() [Advanced I/O] Generates a square wave of the specified frequency (and 50% duty cycle) on a pin. A duration can be specified, otherwise the wave continues until a call to notone(). The pin can be connected to a piezo buzzer or other speaker to play tones. Only one tone can be generated at a time. If a tone is already playing on a different pin, the call to tone() will have no effect. If the tone is playing on the same pin, the call will set its frequency. Use of the tone() function will interfere with PWM output on pins 3 and 11 (on boards other than the Mega). It is not possible to generate tones lower than 31Hz. For technical details, see Brett Hagman s notes. tone(pin, frequency) tone(pin, frequency, duration) pin: the pin on which to generate the tone Physical Computing and Embedded Sytems Page 7

8 frequency: the frequency of the tone in hertz - unsigned int duration: the duration of the tone in milliseconds (optional) - unsigned long From < notone() [Advanced I/O] Stops the generation of a square wave triggered by tone(). Has no effect if no tone is being generated. notone(pin) pin: the pin on which to stop generating the tone From < See Item 4 for details about the tone() function. digitalwrite(trigpin, HIGH); delaymicroseconds(10); digitalwrite(trigpin, LOW); duration = pulsein(echopin, HIGH); distance = (duration/2) / 29.1; // send an ultrasonic pulse // for 10 ms // turn off ultrasonic pulse // measure the time (ms) it takes for the INPUT pin pulse to go from HIGH to LOW and store in variable called duration // distance is calculated as half the duration (time to reach object, rather than there and bounce back) divided by speed of sound (29.1cm/ms) When we flash the trigger pin high for a small amount of time (in this case 1000 microseconds), the sensor would send an ultrasonic wave at a known time (let's say t1), the wave will reach the object and reflect back to the sensor at another known time (t2), lets assume t3 =t2 - t1, (t3 is equal to the time taken for the wave to reach the object and comeback, so t3/2 is the time needed for the wave to reach the object) we know the speed of sound which is 340 m/s or 29.1cm/ms so we are able to get the distance in cm if (distance >= 200 distance <= 0) { Serial.println("no object detected"); digitalwrite(buzzer,low); //when distance is greater than or equal to 200 OR less than or equal to 0,the buzzer and LED are off // ie As long as there is nothing less than 200 cm away the buzzer is off //print to monitor // buzzer off else { // if there is an object within 200cm Serial.println("object detected \n"); // print to monitor Serial.print("distance= "); Serial.print(distance); //prints the distance if it is between the range 0 to 200 // play a tone similar to a police siren; you could re-write as a loop tone(buzzer, 400); // play 400 Hz tone for 500 ms delay(500); tone(buzzer, 800); // play 800Hz tone for 500ms delay(500); tone(buzzer, 400); // play 400 Hz tone for 500 ms delay(500); tone(buzzer, 800); // play 800Hz tone for 500ms delay(500); tone(buzzer, 400); // play 400 Hz tone for 500 ms delay(500); tone(buzzer, 800); // play 800Hz tone for 500ms delay(500); notone(buzzer); INSTRUCTIONS 1. Save the sketch (code) below and then open in the Arduino IDE (File>Open..) Burglar_Ala rmed Physical Computing and Embedded Sytems Page 8

9 Burglar_Ala rmed 2. Copy the code into a place where you can edit it to add comments. 3. Answer the following: Portfolio Task Questions for DEVELOP 1. Where are the Input, output, storage in the code? Feature Code 2. How does the code work - pseudocode a. Copy the existing code b. Place comments (//) next to each line of code in pseudocode 3. How will you modify the circuit and/or the code to make it do something different or more effectively? 4. How could you use this technology in another way to improve the way it works or apply it to a different situation? How to write pseudocode Accepting inputs Operation Pseudocode Programming equivalent Prompt user for surname Input surname var person = prompt("please enter your name"); Producing outputs Print the message Hello World console.log( Hello World ); Assigning values to variables Set the total to 0 var total = 0; Performing arithmetic set total to items times price var total = items * price; Selection and Perform alternative actions Iteration or Repeating operations 1. Pre-test loop also known as the WHILE loop Iteration or Repeating operations 2. Post-test loop eg the REPEAT/UNTIL or DO/WHILE loops Iteration or Repeating operations 3. Counting loop also known as the FOR loop. IF mark is greater than 49 THEN print Pass ELSE print Fail WHILE total greater than 0 subtract new purchase from total ENDWHILE REPEAT <Block> UNTIL condition FOR Index = START_VALUE to FINISH_VALUE <Block> ENDFOR if (mark > 49) { console.log( Pass ); else { console.log( Fail ); while (total > 0) { total = total - new_purchase; var i = 0; do { text += "The number is " + i; i++; while (i < 5); var i; for (i = 0; i < cars.length; i++) { text += cars[i] + "<br>"; GENERATE WALT: design and implementation of modular programs, including an object-oriented program, using algorithms and data structures involving modular functions that reflect the Physical Computing and Embedded Sytems Page 9

10 program, using algorithms and data structures involving modular functions that reflect the relationships of real-world data and data entities WILF - Code implemented Processes and production skills Generating and designing - producing and implementing A B C The student work has the following characteristics: The student work has the following characteristics: The student work has the following characteristics: purposeful design and proficient implementation of modular programs, including an object-oriented program, using algorithms and data structures involving modular functions that reflect the relationships of real-world data and data entities - All code implemented effective design and effective implementation of modular programs, including an object-oriented program, using algorithms and data structures involving modular functions that reflect the relationships of real-world data and data entities - Most code implemented design and implementation of modular programs, including an object-oriented program, using algorithms and data structures involving modular functions that reflect the relationships of real-world data and data entities - Some code implemented INSTRUCTIONS 1. Set up the circuit. Take a photo for your portfolio, or set up a virtual circuit in tinkercad and take a screenshot. 2. Test your board with the 'Blink' sketch 3. Save the sketch (code) below and then open in the Arduino IDE (File>Open..) Burglar_Ala rmed 4. Double-check that you have the right board (Tools>Board) and COM port (Tools>Port) selected. 4.5 Switch on the Monitor to see sensor values 5. Upload your sketch (Sketch>Upload or 6. You should hear an alarm going off Youtube Video: 7. Copy and paste the code to your portfolio. Read and translate the code into pseudocode by commenting (add \\ at the end of each line) each line of code. Eg: pinmode(11, OUTPUT); // set pin 11 as an output pin 8. Modify the code to make it work differently or more effectively. Eg. Change the distance to trigger the alarm, change the tone 9. Re-upload your code 10. Take a video for your portfolio. 11. Answer the questions below: Portfolio Task Questions for GENERATE 1. Get the hardware and software working 2. Get your modifications working and highlight where you have altered the code. document 3. Record a very short video of your working solution. Physical Computing and Embedded Sytems Page 10

11 EVALUATE AND REFINE WALT: evaluation of information systems and their solutions in terms of risk, sustainability and potential for innovation and enterprise WILF - Makes judgments about ideas, works, solutions or methods in relation to risk, sustainability and potential for innovation and enterprise Processes and production skills Evaluating A B C The student work has the following characteristics: The student work has the following characteristics: The student work has the following characteristics: discerning evaluation of information systems and their solutions in terms of risk, sustainability and potential for innovation and enterprise - All sections of evaluation completed and thorough. informed evaluation of information systems and their solutions in terms of risk, sustainability and potential for innovation and enterprise - Most sections of evaluation completed and thorough. evaluation of information systems and their solutions in terms of risk, sustainability and potential for innovation and enterprise - Most sections of evaluation completed. Portfolio Task Questions for EVALUATE AND REFINE 1. Update your kanban and burndown chart 2. Write a short evaluation Evaluation Critically evaluate your completed digital solution by using the organiser below. Make sure that you use full sentences and copy and paste text into paragraphs rather than leaving it in table form. Digital solution evaluation Enterprise needs and opportunities What needs or opportunities does the solution address? Risks What risks does the digital solution pose to the user s personal security? Could the digital solution have any adverse effects on the stakeholders? Sustainability How could the digital solution impact the environment? What economic factors might influence the digital solution? Is your solution easy to use and learn? Why/Why not? Are there any social factors which could affect the solution? Innovative How is the digital solution innovative? Recommendations Recommend at least one improvement that you would like to see made to the digital solution. Physical Computing and Embedded Sytems Page 11

12 Want More? SkillsSheet &fbclid=iwar1dk4ti2pyghy16wztjzvbbnvc4ewoy5rgwrta-fayvumlasdnecqtwfcy Portable Ultrasonic Range Meter Extension - solution using arrays: int distance() { int16_t array[3] = {; for(int count = 0; count < 2; count++){ float duration, distance; digitalwrite(7, HIGH); delaymicroseconds(10); digitalwrite(7, LOW); duration = pulsein(6, HIGH) / 2 * ; delay(20); array[count] = duration; int measure = array[0] += array[1] += array[2]; return measure / 3; int repeat = 4; void setup() { pinmode(7, OUTPUT); pinmode(6, INPUT); pinmode(11, OUTPUT); Serial.begin(9600); void loop() { Serial.println(distance()) if (distance() < 10) { for (int count = 0; count < repeat; count++) { digitalwrite(11, HIGH); delay(250); digitalwrite(11, LOW); delay(250); Physical Computing and Embedded Sytems Page 12