MCP9808 digital temperature sensor example
The MCP9808 digital temperature sensor converts temperatures between -20°C and +100°C to a digital word with ±0.5°C (max.) accuracy. The MCP9808 comes with user-programmable registers that provide flexibility for temperature sensing applications. The registers allow user-selectable settings such as Shutdown or low-power modes and the specification of temperature Event and Critical output boundaries. When the temperature changes beyond the specified boundary limits, the MCP9808 outputs an Event signal.
The user has the option of setting the event output signal polarity as an active-low or active-high comparator output for thermostat operation, or as temperature event interrupt output for microprocessor-based systems. The event output can also be configured as a Critical temperature output.
This sensor has an industry standard 2-wire, SMBus and Standard I2C™Compatible compatible (100kHz/400kHz bus clock) serial interface, allowing up to eight sensors to be controlled in a single serial bus.
Features
Accuracy:
±0.25°C (typical) from -40°C to +125°C
±0.5°C (maximum) from -20°C to +100°C
User Selectable Measurement Resolution:
0.5°C, 0.25°C, 0.125°C, 0.0625°C
User Programmable Temperature Limits:
Temperature Window Limit
Critical Temperature Limit
User Programmable Temperature Alert Output
Operating Voltage Range: 2.7V to 5.5V
More details about the sensor at http://www.microchip.com/wwwproducts/en/MCP9808
This typically comes in a breakout such as the one in the breakout below
mcp9808 breakout
Layout
Software
[codesyntax lang=”bash”]
git clone https://github.com/adafruit/Adafruit_Python_MCP9808.git cd Adafruit_Python_MCP9808 sudo python setup.py install
[/codesyntax]
Run it like this
[codesyntax lang=”bash”]
cd examples sudo python simpletest.py
[/codesyntax]
Here is the code for simpletest.py
[codesyntax lang=”python”]
import time
import Adafruit_MCP9808.MCP9808 as MCP9808
def c_to_f(c):
return c * 9.0 / 5.0 + 32.0
sensor = MCP9808.MCP9808()
# Initialize communication with the sensor.
sensor.begin()
# Loop printing measurements every second.
print 'Press Ctrl-C to quit.'
while True:
temp = sensor.readTempC()
print 'Temperature: {0:0.3F}*C / {1:0.3F}*F'.format(temp, c_to_f(temp))
time.sleep(1.0)
[/codesyntax]
Results
You should see this in the terminal window
mcp9808
Links
Adafruit MCP9808 High Accuracy I2C Temperature Sensor Breakout Board [ADA1782]
