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→Improving the code
The following scope capture show the 3V3 rail at very low current. As shown, je 3V3 contains lot of noise (Saw Waveform).
The following scope capture show the 3V3 rail at very low current. As shown, je 3V3 contains lot of noise (Saw Waveform).
[[Fichier:Pico-3V3-regulation-at-low-current.png|480px]]
[[Fichier:Pico-3V3-regulation-at-low-current.png|640px]]
As the analog sensors are very sensitive to unstable power voltage. Variation and noise on power rail may cause important variation on analog output of an analog sensor.
As the analog sensors are very sensitive to unstable power voltage. Variation and noise on power rail may cause important variation on analog output of an analog sensor.
[[Fichier:Pico-TMP36-improved-wiring.png|480px]]
[[Fichier:Pico-TMP36-improved-wiring.png|480px]]
By adding the 2200µF capacitor, the noisy saw waveform will be changed and adding the 10nF will greatly reduce the noise opn the PowerRail.
[[Fichier:Pico-TMP36-improved-wiring-2.png|640px]]
== Improving the code ==
A good way to improve stability in the readings is to preform a means calculation over several reading.
<syntaxhighlight lang="python">
# Mean read the TMP36 analog temperature
# sensor wired to ADC0 (GP26)
#
from machine import ADC, Pin
import time
adc = ADC(Pin(26))
while True:
value = 0
for i in range(10):
value += adc.read_u16()
value /= 10
mv = 3300.0 * value / 65535
temp = (mv-500)/10
print( 'Temp: %5.2f °C, Voltage: %4i mV' % (temp,mv) )
time.sleep(0.100 )
</syntaxhighlight>
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