Driving a hundred solenoid valves

As I discussed in this past post about MIDIJets, I was attempting to make a platform for surveying microjet actuator location and parameters in aerodynamic flows for my PhD research. But I think this is something that can be quite useful in many other contexts. After working with this for a couple months now and realizing how robust the driver I developed was (yes, I’m proud!), I decided to release this project as an open-source hardware. Maybe someone else might find this useful?!

With that said, the project files can be found at this GitHub page: https://github.com/3dfernando/Jexel-Driver . The files should be sufficient for you to both build your own board, program it with a PICKit4 (I’m pretty sure you should be fine with older PICKit versions) and communicate with the Serial port through a USB connection.

What can I do with it?

Now, let’s talk about the device’s uses. Being able to control many solenoids with a single board can be very useful. In my case, the application is aerodynamic research. We can activate or energize a boundary layer of a flow. But maybe the applications could transcend aerodynamic research? Imagine a haptic feedback glove that makes vibrating air jets on your fingers, how cool would that be? Or maybe an object manipulator by controlling where air is issuing from? I think there’s some other possibilities to be explored. If you would like to replicate this, let me know.

Visualizing the jets

Here’s some quick flow-vis showing the pulsating jets with a small phase delay of 60º. Just as a reminder, visualizing jets of 0.4mm diameter is not easy – so I apologize if the video looks noisy! There’s a dust particle floating in the air in some frames. That’s kinda distracting but is not part of the experiment!

Some caveats

Well, I’m a mechanical engineer, so board design is not really something I do professionally. Therefore, expect some issues or general weirdnesses with my design. If you’d like to replicate this, I used a Matrix Pneumatix DCX321.1E3.C224 solenoid. It is not a large valve. The right connector is on the project BOM. The issue is that this valve is a high voltage, low current valve (24V, 50mA). The driver shield I designed has those specs in mind. This means a different driver circuit would probably be needed for valves with different specs. Also, for higher currents, be mindful that the motherboard carries the current through it, possibly generating some noise if the driver current is too high (yes, I was not very smart in the board design!).

In conclusion

Well, I hope you found this mildly interesting. If you think you could use this project and you made something cool inspired by this, I would be pleased to know!

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