131 Week 8 - micro:bit buttons, temps, logs

Question 1

How to access buttons in CODAL

Answer 1

uBit.buttonA, uBit.buttonB and uBit.buttonAB for button A, button B and button A+B respectively

Question 2

Detecting button presses

Answer 2

.isPressed() returns 1 or 0 if the specified button has been pressed.
Synchronous programming, detection of buttons is done in main() function.

Question 3

Asynchronous programming

Answer 3

Asynchronous detection determines when something has happened rather than if it has happened.
MicroBitMessageBus class is to listen to events and delivers MicroBitEvents as they occur.
When an event of interest is detected, MicroBitMessageBus class calls a function linked to that event, known as an event handler.

Question 4

release_fibre()

Answer 4

Used in asynchronous programming to stop exiting main() once code is executed so that we can use messageBus.listen();
Place at the end of the main() function.

Question 5

Detecting an event

Answer 5

uBit.messageBus.listen(MICROBIT_ID_BUTTON_AB, MICROBIT_BUTTON_EVT_CLICK, onButtonAB);
Has 3 arguments:
ID of component to listen to
Event of interest
Event handler to be called if event is called

Question 6

Wildcard event

Answer 6

Event ID of: MICROBIT_EVT_ANY
Allows event handler to be called if the component raises any events

Question 7

Event handler

Answer 7

void onButtonAB(MicroBitEvent e)
Name has to match the argument in messageBus.listen()
Has 1 argument which stores the event that was raised
Can use e.value to return the ID of the event that was raised.

Question 8

MicroBitThermometer

Answer 8

A class that lets you return the surface temperature of the application MCU - not the ambient temperature

Question 9

Get uncalibrated temp reading

Answer 9

readTemp = uBit.thermometer.getTemperature();

Question 10

Calibrating the temperature

Answer 10

Can measure ambient temperature if we know the real temperature by calibrating the thermometer:
uBit.thermometer.setCalibration(readTemp-ambientTemp);
readTemp = uBit.thermometer.getTemperature();

Question 11

Asynchronous temperature reading

Answer 11

uBit.messageBus.listen(MICROBIT_ID_THERMOMETER, MICROBIT_THERMOMETER_EVT_UPDATE, eventHandlerName);

Question 12

Sampling period

Answer 12

The time between temperature readings.
Can be set using:
uBit.thermometer.setPeriod(time in ms);

Question 13

Logging data

Answer 13

need #include “MicroBitLog.h”
Allows storing of data in a table like format containing rows of readings or other types of data.

Question 14

How to log data

Answer 14

beginRow() – open a file and create a new row
logData(“label of column”, value_to_log) - identify the label of the column where a value will be entered in the new row.
endRow() - complete logging and close the file.

Question 15

Timestamp

Answer 15

A timestamp can be added before data is started to be collected and logged.
Not necessary but it allows you to create a plot of recorded values.
uBit.log.setTimeStamp(TimeStampFormat::Seconds);

Question 16

Access the log file

Answer 16

uBit.log.setVisibility(true);
Allows you to find the log file (named MY_DATA.HTM) in the micro:bit folder and access it using a browser.

Question 17

Check if the log is full

Answer 17

uBit.log.isFull() returns 0 if the log isn’t full and 1 if it is

Question 18

Clear the log

Answer 18

uBit.log.clear(); clears the contents of the log file