Configure sparging and electrolysis

1. On the Configuration page, check config.ini contains the following. The installer adds 4=relay and the [electropioreactor.config] section; channel 3 was set to waste in Nutrient solution.

   [PWM]
   # map the PWM channels to externals.
   # hardware PWM are available on channels 1 & 3.
   1=stirring
   2=media
   3=waste
   4=relay
   5=heating
   
   [electropioreactor.config]
   electrolysis_power=2.5              ; LED D intensity (0-10 %, clamped at runtime)
   sparge_duration_seconds=10.0        ; solenoid open time per cycle (s)
   sparge_interval_minutes=60.0        ; cycle frequency (min)
   od_pause_after_sparge_seconds=5.0   ; OD settle window after sparge ends (s)

2. Open electroPioreactor from Activities on the Manage screen.

3. Set a test spargeBubbling gas through the culture. Here, CO₂ from the cylinder flows down the anode on a timer set in the electroPioreactor job. in the job’s Settings panel: interval 1 minute, duration 1 second.

4. Listen for the solenoidAn electric valve on PWM channel 4 that opens to sparge. It must be 3-way venting (3/2), so the line vents when it closes. clicking open at each sparge.

5. Open the needle valveA fine-adjustment valve on the solenoid's front port. It sets how fast CO₂ flows; turn clockwise to close. while watching the vial, until the bubbling looks right.

6. Set your working sparge interval and duration in the job’s Settings panel.

   

Notes

• All four parameters are editable live from Settings. od_pause_after_sparge_seconds applies from the next sparge.
• ElectrolysisSplitting water with an electric current: hydrogen at the cathode, oxygen at the anode. It supplies the hydrogen the HOB grow on. power stays clamped to 10% at runtime to protect the electrodes.

Parts

• 1×Solenoid valveearlier step

Check your work

1. What does config.ini show for PWMOne of the HAT's five switched power outputs. In this build: 1 stirring, 2 media pump, 3 waste (product) pump, 4 CO₂ solenoid (relay), 5 heating. 4 and the plugin?

   • 4=waste, and an [electropioreactor.config] section
   • 4=relay, but no [electropioreactor.config] section
   • 4=relay, and an [electropioreactor.config] section
   Show the answer

   Answer: 4=relay, and an [electropioreactor.config] section

   • If you see 4=waste, and an [electropioreactor.config] section: Set PWM 4 to relay on the UI's Configuration page (see Check the plugin).
   • If you see 4=relay, but no [electropioreactor.config] section: Re-run the plugin install (see Check the plugin). The installer patches config.ini.

2. At each test spargeBubbling gas through the culture. Here, CO₂ from the cylinder flows down the anode on a timer set in the electroPioreactor job., what do you hear and see?

   • A click, then CO₂ bubbling into the vial
   • A click, but no bubbling in the vial
   • No click, and no bubbling in the vial
   Show the answer

   Answer: A click, then CO₂ bubbling into the vial

   • If you see A click, but no bubbling in the vial: Check the adapter pin and the regulatorDrops the cylinder's pressure (about 60 bar when full) to a working pressure, about 1 bar here. Its flathead screw fully anti-clockwise is closed. are open, then open the needle valveA fine-adjustment valve on the solenoid's front port. It sets how fast CO₂ flows; turn clockwise to close.: CO₂ gas train left it closed.
   • If you see No click, and no bubbling in the vial: Check the 12V supply is in the HATThe Pioreactor circuit board that plugs onto the Raspberry Pi's pin header. It carries the PWM and LED outputs and the 12V barrel jack.'s barrel jack and the shuntA small jumper on the HAT. In the position closest to the LED outputs it feeds the 12V supply to PWM channels 1 to 4. is on the pins closest to the LED outputs (Raspberry Pi and HAT). Without both, PWMOne of the HAT's five switched power outputs. In this build: 1 stirring, 2 media pump, 3 waste (product) pump, 4 CO₂ solenoid (relay), 5 heating. 4 cannot drive the solenoidAn electric valve on PWM channel 4 that opens to sparge. It must be 3-way venting (3/2), so the line vents when it closes..

3. Which parameters can you change in the job's Settings panel?

   • All four, including the OD pause
   • Three: an OD pause change seems ignored
   Show the answer

   Answer: All four, including the OD pause

   • If you see Three: an OD pause change seems ignored: It is not ignored: od_pause_after_sparge_seconds takes effect on the next spargeBubbling gas through the culture. Here, CO₂ from the cylinder flows down the anode on a timer set in the electroPioreactor job. cycle, not the one in progress.

≈ 0.02 g CO₂e per view