Programming with MicroPython: Onboard Sensors

Import FutureBoard Library

Import the Library to make use of its functions.

from future import *

02: Onboard Sensors

1. Buttons

sensor.btnValue(btn)

Parameter btn represents A or B button, accepted values are a, b.

2. Light Sensor

sensor.getLight()

Returns a value 0~4095.

3. Temperature Sensor

sensor.getTemp()

Returns a degree in Celsius, FutureBoard can measure temperatures from -40 to 80 degrees.

Sample Program for 1~3

from future import *

from time import sleep

screen.fill((0, 0, 0))
while True:
  if sensor.btnValue('a'):
    screen.text(str("Light: ")+str(sensor.getLight()),5,10,1,(0, 119, 255))
    sleep(0.5)
  if sensor.btnValue('b'):
    screen.text(str("Temp: ")+str(sensor.getTemp()),5,30,1,(0, 119, 255))
    sleep(0.5)

---

4. Accelerometer

sensor.accX()
sensor.accY()
sensor.accZ()

Returns the accelerometer value of the 3 axis with G as the unit.

5. Tilt Angles

sensor.roll()
sensor.pitch()

Returns the roll and pitch angle of the FutureBoard.

Sample Program for 4~5

#The screen displays the readings of the accelerometer.

from future import *

from time import sleep

screen.sync = 0
while True:
  screen.fill((0, 0, 0))
  screen.text(str("X: ")+str(sensor.accX()),5,10,1,(0, 119, 255))
  screen.text(str("Y: ")+str(sensor.accY()),5,25,1,(0, 119, 255))
  screen.text(str("Z: ")+str(sensor.accZ()),5,40,1,(0, 119, 255))
  screen.text(str("Roll: ")+str(sensor.roll()),5,55,1,(0, 119, 255))
  screen.text(str("Pitch: ")+str(sensor.pitch()),5,70,1,(0, 119, 255))
  screen.refresh()
  sleep(0.2)

---

6. Gesture Detection

sensor.gesture(gesture)

8 kinds of gesture can be detected by the FutureBoard.

1. ‘shake’

2. ‘freefall’

3. ‘tilt_up’

4. ‘tilt_down’

5. ‘tilt_left’

6. ‘tilt_right’

7. ‘face_up’

8. ‘face_down’

7. Gesture Event Trigger

sensor.gesTrig[ges] = fn
sensor.startSchedule()

Sample Program for 6~7

# Futureboard plays a melody on shake.
# Futureboard shows the status of gestures face up and face down.

from future import *

from time import sleep

def onGesture_shake():
  buzzer.melody(JUMP_UP)

sensor.gesTrig['shake']=onGesture_shake
sensor.startSchedule()

screen.sync = 0
while True:
  screen.fill((0, 0, 0))
  screen.text(str("Face Up: ")+str(sensor.gesture('face_up')),5,10,1,(0, 119, 255))
  screen.text(str("Face Down: ")+str(sensor.gesture('face_down')),5,25,1,(0, 119, 255))
  screen.refresh()
  sleep(0.2)

---

8. Compass Calibration

calibrateCompass()

Magnetometer and compass requires calibration before using.

9. Magnetic Strength

sensor.magX()
sensor.magY()
sensor.magZ()
sensor.magStrength()

Returns the magnetic strength detected by the sensor with uT as the unit.

10. Compass Bearing

sensor.heading()

Returns the compass bearing.

Sample Program for 8~10

# Simulates a compass

from future import *
import math
calibrateCompass()
screen.sync = 0
ds = ''
while 1:
    d = int(math.fabs(360-sensor.heading()))
    screen.fill(44)
    if (d<20) | (d>340):
        ds = 'N'
    elif (d<70):
        ds = 'NE'
    elif (d<110):
        ds = 'E'
    elif (d<160):
        ds = 'SE'
    elif (d<200):
        ds = 'S'
    elif (d<250):
        ds = 'SW'
    elif (d<290):
        ds = 'W'
    else:
        ds = 'NW'
    screen.text(d, 5,5)
    screen.textCh(ds,5,30)
    screen.text(str('Strength: ')+str(sensor.magStrength()),5,80)
    screen.refresh()