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RASP-PYGAME-GUI-Analogique (voir la source)
Version du 11 juillet 2016 à 10:27
, 11 juillet 2016 à 10:27aucun résumé de modification
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== Entrée Analogique ==
{{ADFImage|RASP-PYGAME-GUI-Analogique-00.jpg}}
This example uses a 10K potentiometer to provide a varying voltage. For analog to digital I normally use an [http://jeremyblythe.blogspot.co.uk/2012/09/raspberry-pi-hardware-spi-analog-inputs.html MCP3008 over SPI]. That's not possible here though because the PiTFT uses both SPI channels on the Pi. So I've switched to an I2C ADC: [http://www.adafruit.com/product/1085 ADS1115 16-Bit ADC - 4 Channel with Programmable Gain Amplifier].
Get the Adafruit Python library:
<syntaxhighlight lang="bash">
cd /home/pi
git clone https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code.git
</syntaxhighlight>
If you need to enable i2c follow this guide: Configuring I2C
{{ADFImage|RASP-PYGAME-GUI-Analogique-01.jpg}}
== Démarrage ==
At the top of this script now we have some more imports for the threading and ADC.
The gain and sample rate are configured and the ADC initialized.
<syntaxhighlight lang="python">
import sys
sys.path.append('/home/pi/Adafruit-Raspberry-Pi-Python-Code/Adafruit_ADS1x15')
import pygame
import os
import pygameui as ui
import logging
import RPi.GPIO as GPIO
import signal
from Adafruit_ADS1x15 import ADS1x15
import threading
import time
ADS1015 = 0x00 # 12-bit ADC
ADS1115 = 0x01 # 16-bit ADC
# Select the gain
# gain = 6144 # +/- 6.144V
gain = 4096 # +/- 4.096V
# gain = 2048 # +/- 2.048V
# gain = 1024 # +/- 1.024V
# gain = 512 # +/- 0.512V
# gain = 256 # +/- 0.256V
# Select the sample rate
sps = 8 # 8 samples per second
# sps = 16 # 16 samples per second
# sps = 32 # 32 samples per second
# sps = 64 # 64 samples per second
# sps = 128 # 128 samples per second
# sps = 250 # 250 samples per second
# sps = 475 # 475 samples per second
# sps = 860 # 860 samples per second
# Initialise the ADC using the default mode (use default I2C address)
# Set this to ADS1015 or ADS1115 depending on the ADC you are using!
adc = ADS1x15(ic=ADS1115)
#Setup the GPIOs as outputs - only 4 and 17 are available
GPIO.setmode(GPIO.BCM)
GPIO.setup(4, GPIO.OUT)
GPIO.setup(17, GPIO.OUT)
log_format = '%(asctime)-6s: %(name)s - %(levelname)s - %(message)s'
console_handler = logging.StreamHandler()
console_handler.setFormatter(logging.Formatter(log_format))
logger = logging.getLogger()
logger.setLevel(logging.DEBUG)
logger.addHandler(console_handler)
os.putenv('SDL_FBDEV', '/dev/fb1')
os.putenv('SDL_MOUSEDRV', 'TSLIB')
os.putenv('SDL_MOUSEDEV', '/dev/input/touchscreen')
MARGIN = 20
</syntaxhighlight>
== Le thread du potentiomètre ==
xxx
{{RASP-PYGAME-GUI-TRAILER}}
{{RASP-PYGAME-GUI-TRAILER}}