Hardware calibrations

Hardware calibrations serve as a method to get accurate performance from your Pioreactor.

Stirring calibration (optional)

info

You'll need the following:

1. Pioreactor HAT
2. Pioreactor sleeve
3. Vial and stirbar

Internally, the Pioreactor will vary the amount of voltage to apply to the stirring motor to reach the desired RPM, however, this can take a few minutes. We can significantly improve this by asking the Pioreactor to create a "map" between voltage and RPM beforehand. Then the Pioreactor only needs to perform a lookup in the map to hit the desired RPM.

note

This is optional, but can really help stirring performance. Creating a stirring calibration is also very easy, so we recommend it.

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Calibrating the stirring in the UI #

1. Start by filling a Pioreactor vial about 3/4th with water, and place the stirbar inside. Close with lid. Place into the Pioreactor.
2. We'll perform this routine through your computer's command line. Need help accessing it?
3. Enter ssh pioreactor@<insert unit name>.local.
   • For example, to calibrate on our Pioreactor named worker3, we typed ssh pioreactor@worker3.local.
   • The default password is raspberry.
4. After SSHing into your Pioreactor, enter pio calibrations run --device stirring.
5. The Pioreactor will increment the voltage applied to the motor, and record the RPM. After it's done, it will collect this data into a calibration curve, and store it locally.
6. At the end, you'll be prompted to set this as the "active" calibration. Select "Yes".

You're done! Your stirring RPM should be much more responsive now.

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Pump calibration

Calibrating a pump, like a low-volume peristaltic pump, is very important to accurately dispense or remove a target volume. There is no liquid feedback loop in the Pioreactor (unlike in the stirring & RPM relationship), so this calibration curve is important.

There are three pumps on the Pioreactor: media, alt-media, and waste. You don't need to have all three available, and can calibrate them one at a time. For calibration, you'll need the following:

1. A pump, with power connection to Pioreactor's PWM outputs
2. An accurate weighing scale, with accuracy of 0.1g or better.
3. Container of water

tip

Supplying external power? Make sure to plug in your external power before pump calibration!

Calibrating the pumps #

1. We'll perform this routine through your computer's command line. Need help accessing it?
2. Enter ssh pioreactor@<insert unit name>.local.
   • For example, to calibrate on our Pioreactor named worker3, we typed ssh pioreactor@worker3.local.
   • The default password is raspberry.
3. To calibrate the media_pump, enter pio calibrations run --device media_pump. Likewise for waste_pump and alt_media_pump.
4. Follow the prompts to calibrate your pump.
5. At the end, you'll be prompted to set this as the "active" calibration. Select "Yes".

Managing calibrations

From both the UI and the command line, you can manage your Pioreactor's calibrations.