Omni directional pressure sensor

Hi All. I’m currently using one of these in buried in a foam cylinder to measure pressure…

It works great as long as the pressure is applied perpendicular to the sensor.

I would love to find a sensor that works in any direction.

Does anyone know of something like that?

THANKS!

I’m not aware of an omnidirectional sensor of this kind, but I would imagine that you could use a barometric sensor.

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This maybe??

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I think a pressure sensor will be better and a lot more accurate, but you could figure out a way to mount three force sensitive resistors along orthogonal axes so that one gave the “X” axis pressure, one the “Y” axis pressure and the final one the “Z” axis pressure. They are arranged like three faces of a cube that all meet in a single corner.

You would then sum the result in some way that is meaningful for your project.

I’d also vote for the pressure sensor.
To increase your accuracy, use a differential pressure sensor to remove the barometric pressure changes caused by normal weather patterns.

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Thanks @Rftop. Do you have one in mind?

That depends on how large of an air bladder you need which will also help determine the expected average & max pressure the Sensor will see.

bladder would be about a 1-2" sphere. pressure about would be a range of hand pressures.

On second thought, temperature changes of the air in the closed system will cause you problems.
I’d bet there is an easier way.

Would something like a mini joystick with force output (voltage) work in your application?
If you give more project details, someone here may have a perfect example for what you’re doing.

@Rftop, Imagine a stress ball with a sensor inside that measures how hard you squeeze. With the directional/flat sensor it works graet, but the squeeze has to be perpendicular to the sensor.

We’d call that a Pneumatic Squeeze Bulb Dynamometer

image

To make a digital one, look for a squeeze bulb and tubing to connect to a differential AMS5812
https://www.analog-micro.com/_pages/sens/ams5812/ams5812_data_sheet.pdf

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Hi @Rftop.

That sensor looks the part but it seems there are no distributors for it in the US. Any other recommendations?

Thanks a million!

Here’s a 15 psi Module and 30 psi, but not just the raw AMS sensors.

But if you’re going to use a fluid (not air) as the medium, you will need a Bidirectional Differential Sensor, not the ones I linked to.

Thanks. We plan to use some kind of air bladder.

Even though those boards are rated for 5V could they be used with an analog in on a particle board and be powered off a single cell LiPo?

NCD (actually a predecessor Control Everything) has an I2C board for the Photon specifically for Battery Power, although I don’t see it on the NCD.io site.
https://shop.controleverything.com/products/particle-electron-or-photon-i2c-shield-for-battery-only-power

But if you plan on using Gen 3 Particle hardware, take a look here:

Isn’t it rather a rebrand or successor?

Hey! Sorry to ask an obivious question. But space is tight and I want to make sure I’m only getting what’s needed.

Can I wire a:

directly to a particle electron:
https://docs.particle.io/datasheets/cellular/electron-datasheet/

If so can you tell me what would be best (analog, I2C)?

Thanks!

Typically you would plug your electron into an adapter shield and then use the NCD I2C cables to connect the adapter to the sensor.

You could hard-wire your electron to the sensor board but how would you do that? Just solder some wire to the bare pins on the electron? Them solder them to the sensor board? You have to use the I2C as far as I can tell. The description page mentions analog but they don’t document any way to read an analog signal from the sensor. So you would have to create a custom cable that connects to the I2C port of the sensor and then bare leads to solder to your electron. Or, de-solder the connectors on the sensor and use patch wire to solder to both the sensor board and the electron. Neither of those ways seem elegant and kinda defeat the purpose of NCD developing a plug-and-play connector system. Also, you will need to manage the I2C pull-ups… you should probably use the pull-up jumpers on the sensor board if you won’t be including them on whatever carrier board you are putting the Electron on.

If you describe, or photograph (best) your setup, maybe I could get a better feel of how you need to wire everything up.

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I have the electron mounted on one of these with in-line sockets…

So that takes care of the electron.

The question is what needs to be wired up to this board. Could a cable come off the board on one of those connectors and get soldered on the breadboard?

This is a prototype for now, eventually a custom board will be made for everything. But we need to prove the concept with the prototype.

THANKS!

The sensor page says one of these cables is included with the sensor board. Just cut one of the connectors off and solder the cut wire ends onto your prototype board. The connector can just plug into the intact connector-end of the cable. Use the NCD I2C Connection Diagram to make sure you get the wires connected correctly.

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