def _test_temperature():
"""Tests the temperature probe"""
for i in range(5):
temperature, res = interfaces.read_temperature()
interfaces.lcd_out("Temperature: {0:0.3f}C".format(temperature), 1)
interfaces.lcd_out("Res: {0:0.3f} Ohms".format(res), 2)
interfaces.delay(0.5)
def drive_step_stick(self, cycles, direction):
"""
cycles and direction are integers
Communicates with arduino to add HCl through pump
:param cycles: number of rising edges for the pump
:param direction: direction of pump
"""
if cycles == 0:
return 0
interfaces.delay(0.01)
if self.serial.writable():
self.serial.write(cycles.to_bytes(4, "little"))
self.serial.write(direction.to_bytes(1, "little"))
self.serial.flush()
wait_time = cycles / 1000 + 0.5
print("wait_time = ", wait_time)
interfaces.delay(wait_time)
temp = self.serial.readline()
if temp == b"DONE\r\n" or temp == b"":
return 0
else:
return int(temp)
else:
interfaces.lcd_out("Arduino Unavailable", 4, constants.LCD_CENT_JUST)
def degas(seconds):
interfaces.lcd_clear()
interfaces.lcd_out("Degassing {0:.0f}".format(seconds), line=1)
interfaces.lcd_out("seconds", line=2)
interfaces.stir_speed_fast()
interfaces.delay(seconds, countdown=True)
interfaces.stir_speed_slow()
def wait_pH_stable(total_sol, data):
"""
Continually polls probes until pH values are stable
:param total_sol: total amount of HCl added to the solution so far
:param data: list of recorded temperature, pH, and solution volume data so far
:return: mean stable pH value of last 10 values
"""
# keep track of 10 most recent pH values to ensure pH is stable
pH_values = [0] * 10
# a counter used for updating values in pH_values
pH_list_counter = 0
# flag to ensure at least 10 pH readings have been made before adding solution
valid_num_values_tested = False
while True:
pH_reading, pH_volts = interfaces.read_pH()
temperature_reading = interfaces.read_temperature()[0]
interfaces.lcd_out("pH: {0:>4.5f} pH".format(pH_reading), line=1)
interfaces.lcd_out("pH V: {0:>3.4f} mV".format(pH_volts * 1000),
line=2)
interfaces.lcd_out("Temp: {0:>4.3f} C".format(temperature_reading),
line=3)
pH_values[pH_list_counter] = pH_reading
if pH_list_counter == 9:
valid_num_values_tested = True
# Check that the temperature of the solution is within bounds
if (abs(temperature_reading - constants.TARGET_TEMPERATURE) >
constants.TEMPERATURE_ACCURACY):
# interfaces.lcd_out("TEMPERATURE OUT OF BOUNDS")
# TODO output to error log
pass
# Record data point (temperature, pH volts, total HCl)
data.append(
(temperature_reading, pH_volts, total_sol, None, None, None, None))
pH_list_counter = 0 if pH_list_counter >= 9 else pH_list_counter + 1
if (valid_num_values_tested and analysis.std_deviation(pH_values) <
constants.TARGET_STD_DEVIATION):
return pH_reading
interfaces.delay(constants.TITRATION_WAIT_TIME)
def titration(pH_target,
solution_increment_amount,
data,
total_sol_added,
degas_time=0):
"""
Incrementally adds HCl depending on the input parameters, until target pH is reached
:param pH_target: target pH for the titration
:param solution_increment_amount: amount of HCl to add to solution. Units of mL
:param data: list of recorded temperature, pH, and solution volume data so far
:param total_sol_added: total amount of HCl added to the solution so far
:param degas_time: optional parameter defining the de-gas time for the solution after the target pH has been reached
:return: total solution added so far
"""
interfaces.lcd_out(
"Titrating to {} pH".format(str(pH_target)),
style=constants.LCD_CENT_JUST,
line=4,
)
# total HCl added
total_sol = total_sol_added
current_pH = wait_pH_stable(total_sol, data)
while current_pH - pH_target > constants.PH_ACCURACY:
interfaces.pump_volume(solution_increment_amount, 1)
if constants.volume_in_pump < 0.05:
# pump in 1 mL
interfaces.pump_volume(1.0, 0)
total_sol += solution_increment_amount
# TESTING SETTLING
interfaces.lcd_out("Mixing...", style=constants.LCD_CENT_JUST, line=4)
interfaces.delay(10) # allow it to mix before taking measurements
current_pH = wait_pH_stable(total_sol, data)
interfaces.temperature_controller.update()
interfaces.lcd_clear()
interfaces.lcd_out("pH value {} reached".format(current_pH), line=1)
interfaces.lcd_out("Degassing " + str(degas_time) + " seconds", line=2)
interfaces.delay(degas_time, countdown=True)
return total_sol
def set_motor_speed(self, target, gradual=False):
if gradual is True:
direction = math.copysign(1, target - self.motor.duty_cycle)
# It won't move under 1000, so this speeds up the process
if direction == 1 and self.motor.duty_cycle < 1000:
self.motor.duty_cycle = 1000
if self.debug:
print("Stirrer set to {0:.0f}".format(self.motor.duty_cycle))
while self.motor.duty_cycle != target:
next_step = min(abs(target - self.motor.duty_cycle), 100)
self.motor.duty_cycle = self.motor.duty_cycle + (next_step * direction)
if self.debug:
print("Stirrer set to {0:.0f}".format(self.motor.duty_cycle))
interfaces.delay(0.1)
else:
self.motor.duty_cycle = target
if self.debug:
print("Stirrer set to {0:.0f}".format(self.motor.duty_cycle))
def test_mode_read_values(numVals=60, timestep=0.5):
numVals = numVals
timestep = timestep
timeVals = np.zeros(numVals)
tempVals = np.zeros(numVals)
resVals = np.zeros(numVals)
pHVals = np.zeros(numVals)
voltVals = np.zeros(numVals)
for i in range(numVals):
temp, res = interfaces.read_temperature()
pH_reading, pH_volts = interfaces.read_pH()
interfaces.lcd_out("Temp: {0:>4.3f} C".format(temp), line=1)
interfaces.lcd_out("Res: {0:>4.3f} Ohms".format(res), line=2)
interfaces.lcd_out("pH: {0:>4.5f} pH".format(pH_reading), line=3)
interfaces.lcd_out("pH V: {0:>3.4f} mV".format(pH_volts * 1000),
line=4)
interfaces.lcd_out("Reading: {}".format(i), 1, console=True)
timeVals[i] = timestep * i
tempVals[i] = temp
resVals[i] = res
pHVals[i] = pH_reading
voltVals[i] = pH_volts
interfaces.delay(timestep)