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C.H.I.P. Computer Analog Input with MCP3008
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| #!/usr/bin/env python3 | |
| # Adapted for CHIP Computer and Python3 from Limor "Ladyada" Fried for Adafruit Industries, (c) 2015 | |
| # This code is released into the public domain | |
| import time | |
| import os | |
| import CHIP_IO.GPIO as GPIO | |
| DEBUG = 1 | |
| # change these as desired - depending on how you cable your CHIP computer with the MCP | |
| SPICLK = "XIO-P3" | |
| SPIMISO = "XIO-P1" | |
| SPIMOSI = "XIO-P0" | |
| SPICS = "XIO-P2" | |
| # read SPI data from MCP3008 chip, 8 possible adc's (0 thru 7) | |
| def readadc(adcnum, clockpin, mosipin, misopin, cspin): | |
| if ((adcnum > 7) or (adcnum < 0)): | |
| return -1 | |
| GPIO.output(cspin, GPIO.HIGH) | |
| GPIO.output(clockpin, GPIO.LOW) # start clock low | |
| GPIO.output(cspin, GPIO.LOW) # bring CS low | |
| commandout = adcnum | |
| commandout |= 0x18 # start bit + single-ended bit | |
| commandout <<= 3 # we only need to send 5 bits here | |
| for i in range(5): | |
| if (commandout & 0x80): | |
| GPIO.output(mosipin, GPIO.HIGH) | |
| else: | |
| GPIO.output(mosipin, GPIO.LOW) | |
| commandout <<= 1 | |
| GPIO.output(clockpin, GPIO.HIGH) | |
| GPIO.output(clockpin, GPIO.LOW) | |
| adcout = 0 | |
| # read in one empty bit, one null bit and 10 ADC bits | |
| for i in range(11): | |
| GPIO.output(clockpin, GPIO.HIGH) | |
| GPIO.output(clockpin, GPIO.LOW) | |
| adcout <<= 1 | |
| if (GPIO.input(misopin)): | |
| adcout |= 0x1 | |
| GPIO.output(cspin, GPIO.HIGH) | |
| return adcout | |
| # set up the SPI interface pins | |
| GPIO.setup(SPIMOSI, GPIO.OUT) | |
| GPIO.setup(SPIMISO, GPIO.IN) | |
| GPIO.setup(SPICLK, GPIO.OUT) | |
| GPIO.setup(SPICS, GPIO.OUT) | |
| def one_channel_track (potentiometer_adc, handler): | |
| "I receive a handler function I will call with only a value from 0 to 100, when it changes." | |
| last_read = 0 # this keeps track of the last potentiometer value | |
| tolerance = 5 # to keep from being jittery we'll only change | |
| # volume when the pot has moved more than 5 'counts' | |
| while True: | |
| # we'll assume that the pot didn't move | |
| trim_pot_changed = False | |
| # read the analog pin | |
| trim_pot = readadc(potentiometer_adc, SPICLK, SPIMOSI, SPIMISO, SPICS) | |
| # how much has it changed since the last read? | |
| pot_adjust = abs(trim_pot - last_read) | |
| if DEBUG: | |
| print( "trim_pot:", trim_pot) | |
| print( "pot_adjust:", pot_adjust) | |
| print( "last_read", last_read) | |
| if ( pot_adjust > tolerance ): | |
| trim_pot_changed = True | |
| if DEBUG: | |
| print( "trim_pot_changed", trim_pot_changed) | |
| if ( trim_pot_changed ): | |
| set_volume = trim_pot / 10.24 # convert 10bit adc0 (0-1024) trim pot read into 0-100 volume level | |
| set_volume = round(set_volume) # round out decimal value | |
| set_volume = int(set_volume) # cast volume as integer | |
| handler(set_volume) # call the handler | |
| last_read = trim_pot # save the potentiometer reading for the next loop | |
| # hang out and do nothing for a half second | |
| time.sleep(0.5) | |
| def two_channel_track (potentiometer_adc_0, potentiometer_adc_1, handler): | |
| "I receive a handler function I will call with values from 0 to 100 of both channels, when at least one changes." | |
| last_read_0 = 0 # this keeps track of the last potentiometer value | |
| last_read_1 = 0 | |
| tolerance = 5 # to keep from being jittery we'll only change | |
| # volume when the pot has moved more than 5 'counts' | |
| while True: | |
| # we'll assume that the pot didn't move | |
| trim_pot_changed = False | |
| # read the analog pin | |
| trim_pot_0 = readadc(potentiometer_adc_0, SPICLK, SPIMOSI, SPIMISO, SPICS) | |
| trim_pot_1 = readadc(potentiometer_adc_1, SPICLK, SPIMOSI, SPIMISO, SPICS) | |
| # how much has it changed since the last read? | |
| pot_adjust_0 = abs(trim_pot_0 - last_read_0) | |
| pot_adjust_1 = abs(trim_pot_1 - last_read_1) | |
| if DEBUG: | |
| print( "trim_pot:", trim_pot_0, ", ", trim_pot_1) | |
| print( "pot_adjust:", pot_adjust_0, ", ", pot_adjust_1) | |
| print( "last_read", last_read_0, ", ", last_read_1) | |
| if ( pot_adjust_0 > tolerance or pot_adjust_1 > tolerance ): | |
| trim_pot_changed = True | |
| if DEBUG: | |
| print( "trim_pot_changed", trim_pot_changed) | |
| if ( trim_pot_changed ): | |
| set_volume_0 = trim_pot_0 / 10.24 # convert 10bit adc0 (0-1024) trim pot read into 0-100 volume level | |
| set_volume_0 = round(set_volume_0) # round out decimal value | |
| set_volume_0 = int(set_volume_0) # cast volume as integer | |
| set_volume_1 = trim_pot_1 / 10.24 # convert 10bit adc0 (0-1024) trim pot read into 0-100 volume level | |
| set_volume_1 = round(set_volume_1) # round out decimal value | |
| set_volume_1 = int(set_volume_1) # cast volume as integer | |
| handler(set_volume_0, set_volume_1) # call the handler | |
| last_read_0 = trim_pot_0 # save the potentiometer reading for the next loop | |
| last_read_1 = trim_pot_1 # save the potentiometer reading for the next loop | |
| # hang out and do nothing for a half second | |
| time.sleep(0.5) | |
| def change_volume (set_volume): | |
| print( 'Volume = {volume}%' .format(volume = set_volume)) | |
| set_vol_cmd = 'sudo amixer cset numid=1 -- {volume}% > /dev/null' .format(volume = set_volume) | |
| os.system(set_vol_cmd) # set volume | |
| if DEBUG: | |
| print( "set_volume", set_volume) | |
| print( "tri_pot_changed", set_volume) | |
| def where_am_i (x, y): | |
| width = 60 | |
| height = 40 | |
| posx = int(x / 100.0 * width) | |
| posy = int(y / 100.0 * height) | |
| os.system('cls' if os.name == 'nt' else 'clear') | |
| for j in range(height, 0, -1): | |
| print(" ") | |
| for i in range (width): | |
| if (i == posx and j == posy): | |
| print("X", end="") | |
| else: | |
| print("_", end="") | |
| # one_channel_track(7, change_volume) # 10k trim pot connected to adc #7 | |
| two_channel_track(5,7, where_am_i) |
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