Bioreactor Control System Official README.md

Table of Contents

• Hardware Requirements

  • Single Board Computer

  • Power Supplies

  • Display

  • Motor Shield

  • Air Compressor

  • Water Pump

  • Relay Module

  • Sensors

• Bioreactor Control System Program Library

  • All Systems Ready

    • bioreactor_control_system

  • Subsystems Testing

    • Motor Shield And Pumps

      • adafruit_motor_shield

      • chamber_pressure_control

      • chamber_flow_control

    • Sensor Readings

      • data_logger

      • pressure_sensor_reading

      • temperature_sensor_reading

      • magnetic_field_sensor_reading

    • Relay Control

      • relay_control

• GUI

  • Home

  • Health

  • Settings

    • Chamber Pressure Settings

    • Flow Rate Settings

    • Magnetic Field Settings

    • Data Logging

Dependencies

The Following list of libraries are essential to be used in bioreactor_control_system as well their respective Subsystems Testing programs.

• OneWire

• DallasTemperature

• Adafruit_MLX90393

• Wire

• Adafruit_MotorShield

• utility/Adafruit_MS_PWMServoDriver

• Nextion

Hardware Requirements

Single Board Computer

Arduino Mega 2560

Power Supplies

• 12V 5A DC source

• 12V 5A DC source

Display

Nextion 5in resistive touch display found here

Air Compressor

12V Brushed DC motor pump found here

Water Pump

12V Brushed DC motor peristaltic pump found here

Motor Shield

Adafruit motorshield V2 found here

Relay Module

5V 8 relay module found here

Sensors

• 5V pressure transducer found here

• 5V digital temperature sensor found here

• 5V Adafruit magnetometer found here

Bioreactor Control System Program Library

All Systems Ready

bio_reactor_control_system

This program encapsulates all the individual programs listed below to control the bioreactor.

Subsystems Testing

Motor Shield And Pumps

adafruit_motor_shield

This program uses the adafruit motor shield library to send PWM signals to a DC motor (up to 4) and is the main source code this is used in both chamber_pressure_control and chamber_flow_control which both use 12V brushed DC motors for the air compressor and peristaltic pump respectively.

chamber_pressure_control

This program uses PID control to pressurize the bioreactor to a specified target pressure. PID is implemented by acquiring the chamber pressure reading as described in pressure_sensor_reading. Once the target pressure is met the air compressor will shut off, then the solenoid valve that is inline with the air compressor will go from open to closed which will seal the bioreactor at the target pressure.

chamber_flow_control

This program inflicts a shear stress on the stem cells in the bioreactor by pumping an aqueous solution through the chamber with the peristaltic pump. The peristaltic pump was calibrated by measuring various PWM values and their corresponding flow rates. The user has the ability to vary the PWM signal from 0-255 which will correspond to a flow rate between 0-0.1L/min respectively.

Sensor Readings

All sensors including the touch screen dispay and SD data logger operate at a baud rate of 9600.

data_logger

This program writes all the sensor readings; described below, to an SD card in .txt format with the SD data logger module. As long as the bioreactor is active, the module will record all sensor readings and once it becomes deactivated, the module will stop the recording process.

pressure_sensor_reading

This program gets the reading from the pressure transducer. The sensor is analog and has a linear relationship between voltage and pressure which is described as follows:

sensor_psi_value = ((sensor_analog_value - pressureMin) * pressuretransducermaxPSI) / (pressureRange)

where:

• sensor_analog_value: raw sensor reading

• pressureMin : analog reading of pressure transducer at 0psi

• pressureMax : analog reading of pressure transducer at 10psi

• pressureRange : pressureMax - pressureMin

• pressuretransducermaxPSI : psi value of transducer being used

temperature_sensor_reading

This program gets the reading from the temperature sensor. A maximum temperature of 50 degrees celcius is set as the cutoff temperature produced by the heating of the magnetic field generation system. If the temperature breaches the maximum temperature, the magnetic field system will automatically shut off by disconnecting its power source through relay_control. The sensor is digital and had a signal conditioning board that converted the digital reading to a reading in celcius.

magnetic_field_sensor_reading

This program gets the reading from the magnetometer sensor. The sensor is located on the top face of the bioreactor and measures the penetrating magentic field on the stem cells. This will provide real time information which will allow the user to make adjustments as needed to stimulate the stem cells under various loading conditions.

Relay Control

relay_control

This program activates or deactivates any of the 8 relays in the bioreactor control center. The 5V relay board is powered independently of the SBC which is ideal so that it is not possible to damage the SBC. The user has the ability to turn on/off any system at any time for convience or experimental reasons but is recommended to use the emergency off switch located on top of the control center to quickly disable the entire relay module which will disconnet power to air compressor, peristaltic pump, solenoid valve, magnetic field system, electric field system and the cooling fan.