Nov 12, 2021
Posted by: Cameron Davidson-Pilon
We care a lot about onboarding. I've seen enough Raspberry Pi projects that seem to require deep experience in software compilers and package management (don't worry if you don't know what those are...) before you can get started. This is an immediate barrier to your project! From a "funnel" perspective, you may end up losing up a large fraction of your users just at this stage. Can we do better?
Nov 04, 2021
Posted by: Cameron Davidson-Pilon
Algae have a very different set of living conditions compared to other organisms that we have tested in the Pioreactor. Algae require both light and CO₂ to grow. We had the foresight to think of algae's unique growing requirements during development, hence the Pioreactor has additional pockets for LEDs in the main body. When these pockets are occupied by white-light LEDs, the Pioreactor turns from a bioreactor into a photo-bioreactor.
Oct 11, 2021
Posted by: Cameron Davidson-Pilon
We just released a new plugin that may be useful for teams that use Slack. The plugin, Logs2Slack, will publish logs from the Pioreactor to a chosen Slack channel, so you and your team can discuss important events in Slack. Installation is quite easy, too!
Oct 06, 2021
Posted by: Cameron Davidson-Pilon
A few months ago, we introduced temperature control via internal heating to the Pioreactor. This has been a success, and something that differentiates us from other bioreactors, but it was creating artifacts in our optical density measurements. Why is that? Well, an LED's brightness varies as the temperature changes: a higher temperature reduces brightness, and lower temperatures increase brightness.
Sep 23, 2021
Posted by: Cameron Davidson-Pilon
The role of stirring in the Pioreactor is important for a few reasons: i) it allows for modest gas exchange between the media and the air, ii) more importantly: it creates a homogenous environment for microbes and nutrients alike. This last point also means that our optical signals won't vary spatially - something that would make the whole system much more complicated.
Sep 13, 2021
Posted by: Cameron Davidson-Pilon
The past few weeks I've been thinking a lot about optics. Too much. It's given me a headache. But we've characterized some really important details about how the Pioreactor works. Let's first talk about how microbial cells interact with light.
Aug 27, 2021
Posted by: Cameron Davidson-Pilon
By design, there is no Pioreactor "cloud". That is, all your collected data, the web interface, and computations are hosted locally on the Raspberry Pis. This has a number of benefits for you, the user:
Aug 20, 2021
Posted by: Cameron Davidson-Pilon
An important metric in bio-processing is the cell density, or biomass, of a bioreactor. The cell density can be measured directly, but the cost of this is very high. Either you are pulling a sample out and counting cells (slow, manual, and noisy), or passing liquid through a flow cytometer (expensive). A common proxy for cell density is optical density: measuring the amount of light scattering off cells. This approach is fast and inexpensive, but has drawbacks, too:
Jul 29, 2021
Posted by: Cameron Davidson-Pilon
In our development boards, we are using the terrific ADS1115 chip to convert our analog optical density signal into digital format that our Raspberry Pi can read. The ADS1115 is a high quality chip: 16-bits (meaning it can output any integer between 0 and 65535), has a programmable gain, and programmable samples-per-second (SPS). Unfortunately, it's also pretty expensive - up to $9 / chip. That's by far the costliest piece on our boards. Fortunately, there is a cheaper chip from the same family: the ADS1015. It's half the price, has 12-bits, and same programming. To make the Pioreactor as affordable as possible, we've done some evaluations and decided to move to the ADS1015.
