NodeMCU Projects: Difference between revisions
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== Projects ==
<syntaxhighlight lang="python">
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<syntaxhighlight lang="python">
import time, math
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Hobby servo motors can be controlled using PWM.
They require a frequency of 50Hz and a duty between about 40 and 115, with 77 being the center value.
*Manual Movements
<syntaxhighlight lang="python">
servo = machine.PWM(machine.Pin(12), freq=50)
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</syntaxhighlight>
*Random movements:
<syntaxhighlight lang="python">
servo = machine.PWM(machine.Pin(12), freq=50)
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servo.duty(urandom.getrandbits(8))
time.sleep(1)
</syntaxhighlight>
* Analog Temperature Meter:
Requirements:
DS18B20 Temperature sensor
Servo Motor
Micropython based NodeMCU
Wiring details:
Servo motor = D4 => GPIO 2
DS18B20 = D7 => GPIO 13
<syntaxhighlight lang="python">
import time
import machine
import onewire, ds18x20
# the device is on GPIO13
dat = machine.Pin(13)
# create the onewire object
ds = ds18x20.DS18X20(onewire.OneWire(dat))
# scan for devices on the bus
roms = ds.scan()
print('found devices:', roms)
# servo is connected to GPIO2
servo = machine.PWM(machine.Pin(2), freq=50)
# Function for mapping range
def translate(value, leftMin, leftMax, rightMin, rightMax):
# Figure out how 'wide' each range is
leftSpan = leftMax - leftMin
rightSpan = rightMax - rightMin
# Convert the left range into a 0-1 range (float)
valueScaled = float(value - leftMin) / float(leftSpan)
# Convert the 0-1 range into a value in the right range.
return rightMin + (valueScaled * rightSpan)
# print all temperatures
while True:
ds.convert_temp()
time.sleep_ms(1000)
for rom in roms:
print(ds.read_temp(rom))
temp = ds.read_temp(rom)
srv = translate(temp, 20, 35, 40, 115)
print(int(srv))
if (temp>=20) & (temp<=35):
servo.duty(int(srv))
else:
print("Out of Range")
</syntaxhighlight>
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