See the Fabulous Workmanship in this Smart Pressure Regulator

For many projects that require control of air pressure, the usual option is to hook up a pump, maybe with a motor controller to turn it on and off, and work with that. If one’s requirements can’t be filled by that level of equipment and control, then it’s time to look at commercial regulators. [Craig Watson] did exactly that, but found the results as disappointing as they were expensive. He found that commercial offerings — especially at low pressures — tended to leak air, occasionally reported incorrect pressures, and in general just weren’t very precise. Out of a sense of necessity he set out to design his own electronically controlled, closed-loop pressure regulator. The metal block is a custom manifold with valve hardware mounted onto it, and the PCB mounted on top holds the control system. The project logs have some great pictures and details of the prototyping and fabrication process.

This project was the result of [Craig]’s work on a microfluidics control system, conceived because he discovered that much of the equipment involved in these useful systems is prohibitively expensive for small labs or individuals. In the course of developing the electronic pressure regulator, he realized it could have applications beyond microfluidics control, and created it as a modular device that can easily be integrated into other systems and handle either positive or negative pressure. It’s especially well-suited for anything with low air requirements and a limited supply, but with a need for precise control.

MIT Makes Lego Lab For Microfluidics

As any good hacker (or scientist) knows, sometimes you find the tools you need in unexpected places. For one group of MIT scientists, that place is a box of Lego. Graduate student [Crystal Owens] was looking for new ways to make a cheap, simple microfluidics kit. This technique uses the flow of small amounts of liquid to do things like sort cells, test the purity of liquids and much more. The existing lab tools aren’t cheap, but [Crystal] realized that Lego could do the same thing. By cutting channels into the flat surface of a Lego brick with a precise CNC machine and covering the side of the brick with glass, she was able to create microfluidic tools like mixers, drop makers and others. To create a fluid resistor, she made the channel smaller. To create a larger microfluidic system, she mounted the blocks next to each other so the channels connected. The tiny gap between blocks (about 100 to 500 microns) was dealt with by adding an O-ring to the end of each of channel. Line up several of these bricks, and you have a complete microfluidic system in a few blocks, and a lab that only costs a few dollars.

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Hackaday Prize Entry: Microfluidics Control System

Microfluidics is the fine art of moving tiny amounts of liquid around and is increasingly used in fields such as biology and chemistry. By miniaturizing experiments, it’s possible to run many experiments in parallel and have tighter control over experimental conditions. Unfortunately, the hardware to run these microfluidic experiments is expensive.

[Craig]’s 2017 Hackaday Prize entry involves creating a microfluidics control system for use by researchers and students. This device allows for miniaturized experiments to be run. This allows more projects to be run in parallel and far more cheaply, as they don’t use as many resources like reagents.

[Craig]’s rig consists of an ESP32, a 40-channel IO expander, 3 pressure regulators tuned to different pressures, and around 2 dozen solenoid valves mounted to manifolds. Solutions are moved around with a combination of two pumps, with one providing positive pressure and one serving as a vacuum pump.

Far cheaper than professional microfluidics systems, [Craig]’s project aims to assist biohackers and underfunded researchers in their pursuits.

Hackaday Prize Entry: Wearable Micro Pump Treats Your Fever for You

Would you strap a tiny pump to your body and let it dose you with medication based on your current vital signs? Most people wouldn’t, while some would appreciate the convenience, and many have no choice. [M. Bindhammer]’s 2017 Hackaday Prize entry, dubbed Sense-Aid, seeks to democratize the drug delivery process somewhat by building a sensor package linked to a tiny surface-mount pump into a single wearable device.

His chosen initial therapeutic area is fever, given that it’s easy to diagnose non-invasively with a simple thermistor and straightforward to treat with antipyretics like acetaminophen. Aside from the obvious regulatory hurdles such a device would face, he’s got a bunch of technical challenges to address. Surprisingly, sourcing a surface-mount pump is not one of them, although finding a medication to pump with it is. Anecdotally, a professor acquaintance of ours used to relate his sure-fire hangover cure: an aspirin tablet dissolved in the polar aprotic solvent dimethyl sulfoxide (DMSO) and absorbed directly through the skin for immediate relief. The story may have been apocryphal, and it certainly sounds like a bad idea, but such solvents may be one way of pumping medications non-invasively.

Obviously, this is only a concept at this point, as [M. Bindhammer] hasn’t even built a prototype yet. But that’s exactly what the first phase of the 2017 Hackaday Prize is all about: Design Your Concept. It may seem like a crazy idea, but at least it’s an idea, and that’s the first step. Have you submitted your idea yet? There’s still plenty of time.

Easy DIY Microfluidics

Microfluidics, the precise control and manipulation of small volumes of liquids, is heavily used in any field that does small-scale experiments with expensive reagents (We’re looking at you, natural sciences.) However, the process commonly used to create microfluidic devices is time and experience intensive. But, worry not: the Uppsala iGEM team has created Chipgineering: A manual for manufacturing a microfluidic chip.

Used while developing everything from inkjet print heads to micro-thermal technologies, microfluidic systems are generally useful. Specifically, Uppsala’s microfluidic device performs a simple biological procedure, a heat-shock transformation, as a proof of concept. Moreover, Uppsala uses commonly available materials: ready to pour PDMS (a biologically compatible silicon) and a 3D printed mold. Additionally, while the team used a resin 3D printer, there seems to be little reason that a fused deposition modeling (FDM) printer wouldn’t work just as well. Particularly interesting is how they sandwich their PDMS between two plates, potentially allowing easy removal and replacement of reagents without external mechanisms. And, to put the cherry on top, Uppsala’s well-illustrated documentation is a joy to read.

This isn’t the first time we’ve covered microfluidic devices, and if you’re still in the prototyping phase, these microfluidic LEGO-like blocks might be what you need. But, if you prefer macrofluidics, this waste shark that aims to clean our oceans might be more your style.

Microfluidic LEGO Bricks

Years ago, prototyping microfluidic systems was a long, time-intensive task. With inspiration from DIY PCB fabrication techniques, that time is now greatly reduced. However, even with the improvements, it still takes a full day to go from an idea to a tangible implementation. However, progress creeps in this petty pace from day to day, and in accordance, a group of researchers have found a way to use 3D printed molds to create microfluidic LEGO bricks that make microfluidic prototyping child’s play.

For the uninitiated, microfluidics is the study and manipulation of very small volumes of water, usually a millionth of a liter and smaller (nL-pL). Interestingly, the behavior of fluids at small scales differs greatly from its larger scale brethren in many key ways. This difference is due to the larger role surface tension, energy dissipation, and fluidic resistance play when distances and volumes are minimized.

By using 3D printed molds to create microfluidic bricks that fit together like LEGOs, the researchers hope to facilitate medical research. Even though much research relies on precise manipulation of minuscule amounts of liquid, most researchers pipette by hand (or occasionally by robot), introducing a high level of human error. Additionally, rather than needing multiple expensive micropipettes, a DIY biohacker only needs PDMS (a silicon-based chemical already used microfluidics) and 3D printed molds to get started in prototyping biological circuits. However, if you prefer a more, ahem, fluid solution, we’ve got you covered.

[via Adafruit]

Microfluidics “Frogger” is a Game Changer for DIY Biology

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See those blue and green dots in the GIF? Those aren’t pixels on an LCD display. Those are actual drops of liquid moving across a special PCB. The fact that the droplets are being manipulated to play a microfluidics game of “Frogger” only makes OpenDrop v 2.0 even cooler.

Lab biology is mainly an exercise in liquid handling – transferring a little of solution X into some of solution Y with a pipette. Manual pipetting is tedious, error prone, and very low throughput, but automated liquid handling workstations run into the hundreds of thousands of dollars. This makes [Urs Gaudenz]’s “OpenDrop” microfluidics project a potential game changer for the nascent biohacking movement by offering cheap and easy desktop liquid handling.

Details are scarce on the OpenDrop website as to exactly how this works, but diving into the literature cited reveals that the pads on the PCB are driven to high voltages to attract the droplets. The PCB itself is covered with a hydrophobic film – Saran wrap that has been treated with either peanut oil or Rain-X. Moving the droplets is a simple matter of controlling which pads are charged. Splitting drops is possible, as is combining them – witness the “frog” getting run over by the blue car.

There is a lot of cool work being done in microfluidics, and we’re looking forward to see what comes out of this open effort. We’ve covered other open source efforts in microfluidics before, but this one seems so approachable that it’s sure to capture someone’s imagination.

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