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@ladyada
Last active October 8, 2015 00:28
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Raspberrry Pi + MCP300 + TMP36 -> Cosm
#!/usr/bin/env python
import time
import os
import RPi.GPIO as GPIO
import eeml
GPIO.setmode(GPIO.BCM)
DEBUG = 1
LOGGER = 1
# 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, True)
GPIO.output(clockpin, False) # start clock low
GPIO.output(cspin, False) # 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, True)
else:
GPIO.output(mosipin, False)
commandout <<= 1
GPIO.output(clockpin, True)
GPIO.output(clockpin, False)
adcout = 0
# read in one empty bit, one null bit and 10 ADC bits
for i in range(12):
GPIO.output(clockpin, True)
GPIO.output(clockpin, False)
adcout <<= 1
if (GPIO.input(misopin)):
adcout |= 0x1
GPIO.output(cspin, True)
adcout /= 2 # first bit is 'null' so drop it
return adcout
# change these as desired - they're the pins connected from the
# SPI port on the ADC to the Cobbler
SPICLK = 18
SPIMISO = 23
SPIMOSI = 24
SPICS = 25
# 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)
# COSM variables. The API_KEY and FEED are specific to your COSM account and must be changed
#API_KEY = '5RNOO3ShYJxYiq2V2sgSRtz3112SAKxFQjNDQmNXc0RScz0g'
#FEED = 68872
API_KEY = 'YOUR_API_KEY'
FEED = YOUR_FEED_ID
API_URL = '/v2/feeds/{feednum}.xml' .format(feednum = FEED)
# temperature sensor connected channel 0 of mcp3008
adcnum = 0
while True:
# read the analog pin (temperature sensor LM35)
read_adc0 = readadc(adcnum, SPICLK, SPIMOSI, SPIMISO, SPICS)
# convert analog reading to millivolts = ADC * ( 3300 / 1024 )
millivolts = read_adc0 * ( 3300.0 / 1024.0)
# 10 mv per degree
temp_C = ((millivolts - 100.0) / 10.0) - 40.0
# convert celsius to fahrenheit
temp_F = ( temp_C * 9.0 / 5.0 ) + 32
# remove decimal point from millivolts
millivolts = "%d" % millivolts
# show only one decimal place for temprature and voltage readings
temp_C = "%.1f" % temp_C
temp_F = "%.1f" % temp_F
if DEBUG:
print("read_adc0:\t", read_adc0)
print("millivolts:\t", millivolts)
print("temp_C:\t\t", temp_C)
print("temp_F:\t\t", temp_F)
print("\n")
if LOGGER:
# open up your cosm feed
pac = eeml.Pachube(API_URL, API_KEY)
#send celsius data
pac.update([eeml.Data(0, temp_C, unit=eeml.Celsius())])
#send fahrenheit data
pac.update([eeml.Data(1, temp_F, unit=eeml.Fahrenheit())])
# send data to cosm
pac.put()
# hang out and do nothing for 10 seconds, avoid flooding cosm
time.sleep(30)
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