ProgramsGPIO Zero Second Edition
We have decided not to make the programs available as a download because this is not the point of the book - the programs are not finished production code but something you should type in and study.
The best solution is to provide the source code of the programs in a form that can be copied and pasted into a VS Code project.
Note: The VS Code task listings are at the very end of this page.
The only downside is that you have to create a project to paste the code into.
To do this follow the instructionin the book- in particular remember to add the bcm2835 library and also any library references that may be needed.
All of the programs below were copy and pasted from working programs in the IDE. They have been formatted using the built in formatter and hence are not identical in layout to the programs in the book. This is to make copy and pasting them easier. The programs in the book are formatted to be easy to read on the page.
If anything you consider important is missing or if you have any requests or comments contact:
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Page 27
from gpiozero import Device
Device()
print(Device.pin_factory.board_info.model)
Page 32
from gpiozero import LED
from time import sleep
led = LED(4)
while True:
led.on()
sleep(1)
led.off()
sleep(1)
Page 52
from gpiozero import LED
from signal import pause
led = LED(4)
led.blink(on_time=1,off_time=1,n=100)
print("Program Complete")
pause()
Page 52
from gpiozero import LED
led = LED(4)
led.blink(on_time=1,off_time=1,n=100,background=False)
print("Program Complete")
Page 58
from gpiozero import LED
from time import sleep
led = LED(4)
while True:
led.toggle()
sleep(1)
led.toggle()
sleep(1)
Page 59
from gpiozero import Buzzer
from signal import pause
buzz = Buzzer(4)
buzz.beep(on_time=1,off_time=1,n=100)
print("Program Complete")
pause()
Page 61
from gpiozero import DigitalOutputDevice
class Lock(DigitalOutputDevice):
def __init__(self,*args,**kwargs):
if 'active_high' in kwargs:
raise TypeError("active_high not supported")
super().__init__(*args,**kwargs)
def lock(self):
super().on()
def unlock(self):
super().off()
def on(self):
raise AttributeError("'Lock' object has no attribute 'on'")
def off(self):
raise AttributeError("'Lock' object has no attribute 'off'")
def blink(self):
raise AttributeError("'Lock' object has no attribute 'blink'")
Page 62
from gpiozero import LED
led1 = LED(4)
led2 = LED(17)
while True:
led1.on()
led2.on()
led1.off()
led2.off()
Page 65
from gpiozero import Device
from time import sleep
Device()
pin=Device.pin_factory.pin(4)
pin._set_function('output')
while True:
pin.state=1
sleep(1)
pin.state=0
sleep(1)
Page 70
from gpiozero import Device
Device()
pin = Device.pin_factory.pin(4)
pin._set_function("output")
while True:
pin.state=1
pin.state=0
Page 98
from gpiozero import Button
from signal import pause
button = Button(4, bounce_time=0.25)
def pressed():
print(“Button pressed”)
def released():
print(“Button released”)
button.when_pressed = pressed
button.when_released = released
pause()
Page 102
from gpiozero import Button
from gpiozero import LED
from time import sleep
button = Button(4)
led1 = LED(17, initial_value=True)
led2 = LED(27)
led3 = LED(22)
state = 0
buttonState = button.value
while True:
buttonNow = button.value
buttonDelta = buttonNow-buttonState
buttonState = buttonNow
if state == 0:
if buttonDelta == 1:
state = 1
led1.off()
led2.on()
led3.off()
continue
if state == 1:
if buttonDelta == 1:
state = 2
led1.off()
led2.on()
led3.off()
continue
if state == 2:
if buttonDelta == 1:
state = 0
led1.on()
led2.off()
led3.off()
continue
sleep(0.1)
Page 103
from gpiozero import Button
from time import perf_counter_ns
button = Button(4)
while True:
button.wait_for_press()
button.wait_for_release()
t1 = perf_counter_ns()
button.wait_for_press()
t2 = perf_counter_ns()
print((t2-t1)/1000000)
Page 104
from gpiozero import Button
from time import perf_counter_ns
button = Button(4)
while True:
while not button.value:
pass
while button.value:
pass
t1 = perf_counter_ns()
while not button.value:
pass
t2 = perf_counter_ns()
print((t2-t1)/1000000)
Page 104
from gpiozero import DigitalInputDevice
from time import perf_counter_ns
pulse = DigitalInputDevice(4)
while True:
while not pulse.value:
pass
while pulse.value:
pass
t1 = perf_counter_ns()
while not pulse.value:
pass
t2 = perf_counter_ns()
print((t2-t1)/1000000)
Page 105
from gpiozero import Device
from time import perf_counter_ns
Device()
pulse = Device.pin_factory.pin(4)
pulse.input_with_pull("up")
while True:
while not pulse.state:
pass
while pulse.state:
pass
t1 = perf_counter_ns()
while not pulse.state:
pass
t2 = perf_counter_ns()
print((t2-t1)/1000000)
Page 105
from gpiozero import DigitalInputDevice
class Door(DigitalInputDevice):
def __init__(self, pin=None, pull_up=True, active_state=None,
bounce_time=None, pin_factory=None):
super(Door, self).__init__(
pin, pull_up=pull_up, active_state=active_state,
bounce_time=bounce_time, pin_factory=pin_factory)
@property
def value(self):
return super(Door, self).value
Door.is_closed = Door.is_active
Door.when_open = Door.when_deactivated
Door.when_closed = Door.when_activated
Door.wait_for_open = Door.wait_for_inactive
Door.wait_for_close = Door.wait_for_active
Page 116
from gpiozero import LightSensor
class Moisture(LightSensor):
def __init__(self, pin=None, queue_len=5, charge_time_limit=0.01, threshold=0.1, partial=False, pin_factory=None):
super(Moisture, self).__init__(pin, threshold=threshold, queue_len=queue_len,
charge_time_limit=charge_time_limit, pin_factory=pin_factory)
Moisture.wait_for_dry = Moisture.wait_for_light
Moisture.wait_for_wet = Moisture.wait_for_dark
Moisture.when_dry = Moisture.when_light
Moisture.when_wet = Moisture.when_dark
Page 119
from gpiozero import PWMLED, DistanceSensor
from signal import pause
led=PWMLED(4)
dist=DistanceSensor(5,6)
led.source=dist
pause
Page 121
from gpiozero import PWMLED, DistanceSensor
from gpiozero.tools import inverted
from signal import pause
led = PWMLED(4)
dist = DistanceSensor(5, 6)
led.source = inverted(dist)
pause
Page 121
from gpiozero import PWMLED, DistanceSensor
from gpiozero.tools import inverted, averaged
from signal import pause
led = PWMLED(4)
front = DistanceSensor(5, 6)
back = DistanceSensor(7, 8)
led.source = averaged(front, back)
pause
Page 122
from signal import pause
from gpiozero import PWMLED, DistanceSensor
from gpiozero.tools import _normalize
def mined(*values):
values = [_normalize(v) for v in values]
for v in zip(*values):
yield min(v)
led = PWMLED(4)
front = DistanceSensor(5, 6)
back = DistanceSensor(7, 8)
led.source = mined(front, back)
pause
Page 123
def PWM_values(period=360, duty=0.5):
_ontime = int(period*duty)
_offtime = period-_ontime
data = [1]*_ontime+[0]*_offtime
while True:
for i in range(_ontime):
print(1)
yield 1
for i in range(_offtime):
print(0)
yield 0
Page 126
from gpiozero import LED, CPUTemperature
from signal import pause
from gpiozero.tools import booleanized
cpu = CPUTemperature(min_temp=58, max_temp=90)
print(cpu.temperature)
led=LED(4)
led.source = booleanized(cpu,0,1)
pause()
Page 126
import io
from gpiozero import InternalDevice
class MemoryFree(InternalDevice):
def __init__(self, threshold=0.9, memfile='/proc/meminfo',
pin_factory=None):
super(MemoryFree, self).__init__(pin_factory=pin_factory)
self._fire_events(self.pin_factory.ticks(), None)
self.memfile = memfile
self.threshold = threshold
self._totalmem = 0
self._availablemem = 0
@property
def free_mem(self):
with io.open(self.memfile, 'r') as f:
self._totalmem = int(f.readline().strip().split()[1])
freemem = int(f.readline().strip().split()[1])
self._availablemem = int(f.readline().strip().split()[1])
return freemem
@property
def value(self):
return self.free_mem/self._availablemem
@property
def is_active(self):
return self.value < 1-self.threshold
Page 127 You need to add the previous class to make this work
from gpiozero import PWMLED
from signal import pause
led = PWMLED(4)
mem = MemoryFree(0.1)
print(mem.value, flush=True)
print(mem.is_active, flush=True)
led.source=mem
pause()
Page 134
from gpiozero import PWMOutputDevice
from signal import pause
pwm = PWMOutputDevice(4)
pwm.frequency = 10000
pwm.value = 0.5
pause()
Page 136
from gpiozero import PWMOutputDevice
pwm = PWMOutputDevice(4)
pwm.frequency = 1000
while True:
pwm.value = 0.1
pwm.value = 0.9
Page 132
from gpiozero import PWMOutputDevice
from time import sleep
pwm = PWMOutputDevice(4)
pwm.frequency = 1000
pwm.value = 0.1
while True:
sleep(0.5)
pwm.toggle()
Page 139
from gpiozero import PWMOutputDevice
from time import sleep
pwm = PWMOutputDevice(4)
pwm.frequency = 1000
steps = 8
delay = 0.01
while True:
for d in range(steps):
pwm.value = d/steps
sleep(delay)
for d in range(steps):
pwm.value = (steps-d)/steps
sleep(delay)
Page 145
from gpiozero import PWMOutputDevice
from time import sleep
pwm = PWMOutputDevice(4)
pwm.frequency = 1000
steps = 8
delay = 0.001
while True:
for d in range(steps):
pwm.value = d/steps
sleep(delay)
for d in range(steps):
pwm.value = (steps-d)/steps
sleep(delay)
Page 153
class uniMotor(PWMOutputDevice):
def __init__(self, pin=None, active_high=True, initial_value=0, pin_factory=None):
super(uniMotor, self).__init__(pin, active_high, initial_value, pin_factory=pin_factory)
def speed(self, value):
self._write(value)
motor = uniMotor(4)
motor.speed(0.5)
sleep(10)
Page 161
from gpiozero import Servo
from time import sleep
servo = Servo(4)
while True:
servo.min()
sleep(0.5)
servo.mid()
sleep(0.5)
servo.max()
sleep(0.5)
Page 162
from gpiozero import Servo
class ServoInvert(Servo):
@Servo.value.setter
def value(self, value):
if value is None:
self.pwm_device.pin.frequency = None
elif -1 <= value <= 1:
self.pwm_device.pin.frequency = int(1 / self.frame_width)
self.pwm_device.value = (self._min_dc + self._dc_range *((value - self._min_value) / self._value_range))
else:
raise OutputDeviceBadValue(
"Servo value must be between -1 and 1, or None")
Page 171
from gpiozero import DigitalOutputDevice
from time import sleep
class StepperBi4():
def __init__(self, A=None, Am=None, B=None, Bm=None):
self.phase = 0
self.gpios = tuple(DigitalOutputDevice(pin) for pin in (A, B, Am, Bm))
self.halfstepSeq = [
[1, 0, 0, 0],
[1, 1, 0, 0],
[0, 1, 0, 0],
[0, 1, 1, 0],
[0, 0, 1, 0],
[0, 0, 1, 1],
[0, 0, 0, 1],
[1, 0, 0, 1]
]
def setPhase(self, phase):
self.phase = phase
for gpio, state in zip(self.gpios, self.halfstepSeq[phase]):
gpio.value = state
def stepForward(self):
self.phase = (self.phase+1) % 8
self.setPhase(self.phase)
def stepReverse(self):
self.phase = (self.phase-1) % 8
self.setPhase(self.phase)
step = StepperBi4(4, 17, 27, 22)
step.setPhase(0)
while True:
sleep(0.001)
step.stepForward()
Page 176
from gpiozero import LED
from time import sleep
class TriLED():
def __init__(self, pin1=None, pin2=None, pin3=None):
self.LEDs = (LED(pin1), LED(pin2), LED(pin3))
def AllOn(self):
self.LEDs[0].on()
self.LEDs[1].on()
self.LEDs[2].on()
def AllOff(self):
self.LEDs[0].off()
self.LEDs[1].off()
self.LEDs[2].off()
Page 177
class TriLED(CompositeDevice):
def __init__(self, pin1=None, pin2=None, pin3=None):
super(TriLED, self).__init__(LED(pin1), LED(pin2), LED(pin3))
def AllOn(self):
self[0].on()
self[1].on()
self[2].on()
def AllOff(self):
self[0].off()
self[1].off()
self[2].off()
Page 192
from gpiozero import DigitalOutputDevice, CompositeDevice
class StepperBi4(CompositeDevice):
def __init__(self, A=None, Am=None, B=None, Bm=None):
if not all(p is not None for p in [A, Am, B, Bm]):
raise GPIOPinMissing(
'Four GPIO pins must be provided'
)
super(StepperUni4, self).__init__(DigitalOutputDevice(A), DigitalOutputDevice(
B), DigitalOutputDevice(Am), DigitalOutputDevice(Bm))
self.phase = 0
self.halfstepSeq = [
[1, 0, 0, 0],
[1, 1, 0, 0],
[0, 1, 0, 0],
[0, 1, 1, 0],
[0, 0, 1, 0],
[0, 0, 1, 1],
[0, 0, 0, 1],
[1, 0, 0, 1]
]
def setPhase(self, phase):
self.phase = phase
for gpio, state in zip(self, self.halfstepSeq[phase]):
gpio.pin._set_state(state)
def stepForward(self):
self.phase = (self.phase+1) % 8
self.setPhase(self.phase)
def stepReverse(self):
self.phase = (self.phase-1) % 8
self.setPhase(self.phase)
Page 194
from gpiozero import DigitalOutputDevice, CompositeDevice
from time import sleep
from gpiozero.threads import GPIOThread
class StepperBi4(CompositeDevice):
def __init__(self, A=None, Am=None, B=None, Bm=None):
if not all(p is not None for p in [A, Am, B, Bm]):
raise GPIOPinMissing('Four GPIO pins must be provided')
super(StepperUni4, self).__init__(DigitalOutputDevice(A), DigitalOutputDevice(
B), DigitalOutputDevice(Am), DigitalOutputDevice(Bm))
self.phase = 0
self._rotate_thread = None
self.halfstepSeq = [
[1, 0, 0, 0],
[1, 1, 0, 0],
[0, 1, 0, 0],
[0, 1, 1, 0],
[0, 0, 1, 0],
[0, 0, 1, 1],
[0, 0, 0, 1],
[1, 0, 0, 1]
]
def setPhase(self, phase):
self.phase = phase
for gpio, state in zip(self, self.halfstepSeq[phase]):
gpio.pin._set_state(state)
def stepForward(self):
self.phase = (self.phase+1) % 8
self.setPhase(self.phase)
def stepReverse(self):
self.phase = (self.phase-1) % 8
self.setPhase(self.phase)
def forward(self, speed=0):
self._stop_rotate()
if speed == 0:
return
self._rotate_thread = GPIOThread(
target=self._rotate, args=(+1, speed))
self._rotate_thread.start()
def reverse(self, speed=1):
self._stop_rotate()
if speed == 0:
return
self._rotate_thread = GPIOThread(
target=self._rotate, args=(-1, speed))
self._rotate_thread.start()
def _rotate(self, dir, speed):
delay = 60/(speed*400)-0.001
while True:
if dir == 1:
self.stepForward()
if dir == -1:
self.stepReverse()
if self._rotate_thread.stopping.wait(delay):
break
def _stop_rotate(self):
if getattr(self, '_rotate_thread', None):
self._rotate_thread.stop()
self._rotate_thread = None
Page 199
import subprocess
temp = subprocess.Popen(["sudo", "dtparam", "-l"], stdout=subprocess.PIPE)
output = str(temp.communicate())
print(output)
lastSPI = output.rfind("spi")
if lastSPI != -1:
lastSPI = output.find("spi=on", lastSPI)
if lastSPI == -1:
temp = subprocess.Popen(
["sudo", "dtparam", "spi=on"], stdout=subprocess.PIPE)
output = str(temp.communicate())
print("adding", output)
else:
temp = subprocess.Popen(
["sudo", "dtparam", "spi=on"], stdout=subprocess.PIPE)
output = str(temp.communicate())
print("adding", output)
Page 190
import subprocess
temp = subprocess.Popen(["sudo", "dtparam", "-l"], stdout=subprocess.PIPE)
output = str(temp.communicate())
print(output)
lastSPI = output.rfind("spi")
if lastSPI != -1:
lastSPI = output.find("spi=on", lastSPI)
if lastSPI == -1:
temp = subprocess.Popen( ["sudo", "dtparam", "spi=on"], stdout=subprocess.PIPE)
output = str(temp.communicate())
print("adding", output)
else:
temp = subprocess.Popen( ["sudo", "dtparam", "spi=on"], stdout=subprocess.PIPE)
output = str(temp.communicate())
print("adding", output)
Page 212
from gpiozero import SPIDevice
Dev=SPIDevice()
Dev.clock_mode=0
Dev.select_high=False
Dev._spi._interface.max_speed_hz=7000
words=Dev._spi.transfer([0xAA])
if words[0]==0xAA:
print("data received correctly")
Page 215
from gpiozero import SPIDevice
Dev = SPIDevice()
Dev.clock_mode = 0
Dev.select_high = False
Dev._spi._interface.max_speed_hz = 60000
words = Dev._spi.transfer([0x01, 0x80, 0x00])
data = (words[1] & 0x03) << 8 | words[2]
volts = data * 3.3 / 1023.0
print(volts)
Dev.close()
Page 220
class DS3234rtc(SPIDevice):
def __init__(self):
super(DS3234rtc, self).__init__()
self.clock_mode = 1
self.select_high = False
self._spi._interface.max_speed_hz = 5000000
def setDateTime(self, dateTime):
datetimetuple = dateTime.timetuple()
datetimetuple = (datetimetuple[0]-2000,)+datetimetuple[1:3] + \
(dateTime.isoweekday(),)+datetimetuple[3:6]
datetimetuple = datetimetuple[::-1]
for i in range(0, 7):
data = datetimetuple[i]
data = (data//10) << 4 | (data % 10)
words = self._spi.transfer([0x80+i, data])
def getDateTime(self):
datetimelist = []
for i in range(7):
words = self._spi.transfer([i, 0x00])
if i == 3:
continue
byte = words[1]
data = (byte & 0x0F)+(byte >> 4)*10
datetimelist.insert(0, data)
datetimelist[0] += 2000
return datetime(*datetimelist)
Page 224
import lgpio
GPIOChip = lgpio.gpiochip_open(0)
lgpio.gpio_claim_output(GPIOChip, 4)
while True:
lgpio.gpio_write(GPIOChip, 4, 0)
lgpio.gpio_write(GPIOChip, 4, 1)
lgpio.gpiochip_close(GPIOChip)
Page 226
import lgpio
GPIOChip = lgpio.gpiochip_open(4)
lgpio.gpio_claim_output(GPIOChip, 4)
lgpio.gpio_claim_output(GPIOChip, 17)
while True:
lgpio.gpio_write(GPIOChip, 4, 1)
lgpio.gpio_write(GPIOChip, 17, 0)
lgpio.gpio_write(GPIOChip, 4, 0)
lgpio.gpio_write(GPIOChip, 17, 1)
lgpio.gpiochip_close(GPIOChip)
Page 229
import lgpio
import time
GPIOChip = lgpio.gpiochip_open(4)
lgpio.tx_pwm(GPIOChip, 4, 1000, 25)
time.sleep(1)
lgpio.tx_pwm(GPIOChip, 4, 1000, 50)
while True:
pass
Page 231
import lgpio
from collections import namedtuple
Pulse = namedtuple('Pulse', ['group_bits', 'group_mask', 'pulse_delay'])
GPIOChip = lgpio.gpiochip_open(4)
lgpio.group_claim_output(GPIOChip, [4,17])
lgpio.tx_wave(GPIOChip, 4,[Pulse(1,3,1000),Pulse(2,3,1000), Pulse(1,3,1000),Pulse(2,3,1000)] )
while True:
pass
Page 232
import lgpio
from collections import namedtuple
Pulse = namedtuple('Pulse', ['group_bits', 'group_mask','pulse_delay'])
GPIOChip = lgpio.gpiochip_open(4)
lgpio.group_claim_output(GPIOChip, [4,17])
while True:
if lgpio.tx_room(GPIOChip,4,lgpio.TX_WAVE)>2:
lgpio.tx_wave(GPIOChip, 4, [Pulse(1,3,1000),Pulse(2,3,1000)])
Page 227 Appendix
settings.json
{
"sshUser": "pi",
"sshEndpoint": "192.168.11.170",
"remoteDirectory": "/home/pi/Documents/",
}
tasks.json
{
"version": "2.0.0",
"tasks": [
{
"label": "copyToRemote",
"type": "shell",
"command": "scp -r ${fileDirname} ${config:sshUser}@${config:sshEndpoint}:${config:remoteDirectory}/",
"problemMatcher": [],
"presentation": {
"showReuseMessage": false,
"clear": true
}
},
{
"label": "makeRemoteWorkSpace",
"type": "shell",
"command": "ssh ${config:sshUser}@${config:sshEndpoint} ;'mkdir ${config:remoteDirectory}'",
"problemMatcher": [],
"presentation": {
"showReuseMessage": false,
}
},
{
"label": "RunR",
"type": "shell",
"command": "ssh ${config:sshUser}@${config:sshEndpoint} ;'python3 ${config:remoteDirectory}/${relativeFileDirname}/${fileBasename}'",
"problemMatcher": [],
"presentation": {
"showReuseMessage": false,
}
},
{
"label": "RunRemote",
"dependsOrder": "sequence",
"dependsOn": [
"copyToRemote",
"RunR"
],
"problemMatcher": [],
"group": {
"kind": "build",
"isDefault": true
},
},
{
"label": "StopRemotePython",
"type": "shell",
"command": "ssh ${config:sshUser}@${config:sshEndpoint} ;'pkill python3'",
"problemMatcher": [],
"presentation": {
"showReuseMessage": true,
}
},
{
"label": "wait",
"type": "shell",
"command": "timeout 10"
},
{
"label": "tunnel",
"type": "shell",
"command": "ssh -2 -L 5678:localhost:5678 ${config:sshUser}@${config:sshEndpoint}",
"problemMatcher": [],
"presentation": {
"showReuseMessage": false,
}
},
{
"label": "startDebug",
"type": "shell",
"command": "ssh -2 ${config:sshUser}@${config:sshEndpoint} ;
'nohup python3 -m debugpy --listen 0.0.0.0:5678 --wait-for-client
${config:remoteDirectory}/${relativeFileDirname}/${fileBasename} > /dev/null 2>&1 &'",
"problemMatcher": [],
"presentation": {
"showReuseMessage": false,
}
},
{
"label": "copyAndDebug",
"dependsOrder": "sequence",
"dependsOn": [
"copyToRemote",
"startDebug",
"wait"
],
"presentation": {
"showReuseMessage": false,
},
},
]
}
launch.json
{
"version": "0.2.0",
"configurations": [
{
"name": "Python: Remote Attach",
"type": "python",
"connect": {
"host": "localhost",
"port": 5678
},
"pathMappings": [
{
"localRoot": "${workspaceFolder}/
${relativeFileDirname}/",
"remoteRoot": "${config:remoteDirectory}/
${relativeFileDirname}"
}
],
"request": "attach",
"preLaunchTask": "copyAndDebug",
"postDebugTask": "StopREmotePython"
}
]
}
