arduino/analog_shield/amplifier_chain/main.py

Prints the amplifier's gain and offset, then once a second the sensor's voltage read directly on A1, the same worked out from the amplifier's output, the amplifier's output (also on J8 pin 4) and the divided signal on A3.

Connect

JP4 on 5 V, JP1 on INT and JP2 on EXT. A meter on J8 pin 4 should match the opamp column.

Uses

raw_sensor_volts(), sensor_volts(), amplifier_volts(), output_volts(), amplifier_gain(), amplifier_offset_volts()

# Prints the voltage at each stage of the temperature amplifier, once a
# second, as columns:
#   A1       the sensor's voltage, read directly
#   sensor   the sensor's voltage, worked out back from the amplifier's output
#   opamp    the amplifier's output (J8 pin 4), sensor * gain - offset
#   A3       the amplifier's output after the R14/R15 divider
#
# Needs analog_shield.py on the board, JP4 on 5 V, JP1 on INT and JP2 on EXT.
# Check the opamp column with a meter on J8 pin 4. With JP1 on EXT, the
# sensor on J1 is measured instead.
 
from arduino import *  # the Arduino-style functions: pinMode(), digitalWrite(), delay(), ...
 
import analog_shield as shield  # the Analog Shield library, used as shield.<name>
 
 
def setup():
    print("gain %.3f, offset %.3f V" % (shield.amplifier_gain(), shield.amplifier_offset_volts()))
    print("A1      sensor  opamp   A3")
 
 
def loop():
    print("%.3f   %.3f   %.3f   %.3f" % (
        shield.raw_sensor_volts(),
        shield.sensor_volts(),
        shield.amplifier_volts(),
        shield.output_volts(),
    ))
    delay(1000)
 
 
# Do not edit below this line: it runs setup() once, then loop() over and over.
def main():
    setup()  # runs once, at the start
    while True:  # repeats until stopped: Interrupt in PyCharm, or mpremote soft-reset
        loop()
 
 
# True when this file is run, but not when another file imports it.
if __name__ == "__main__":
    main()