Kujoejoe
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Raspi pressure sensor

Sun Aug 11, 2019 7:07 am

I'm trying to build a robot using this Raspberry Pi but frankly I'm not educated and I don't understand these things very well I'm working on teaching myself to code but I'm hoping someone can explain to me how these pressure sensors work. When it is connected to the Raspberry Pi How Will I Know what the pressure translates to. What I mean is will there be a screen where it presents members or something based on each touch. Also I am learning Java to program is there something more appropriate for Raspberry Pi I should be starting with?

As I mentioned before I'm not very well educated I know this I don't need people pointing that out. If you can't or don't want to help that is okay I'm just hoping for a little helpful input.

Andyroo
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Re: Raspi pressure sensor

Sun Aug 11, 2019 12:11 pm

Welcome to the forum.

We all have to start somewhere so do not worry about that as the forum members help beginners to experts.

I would start by having a read of some of the back issues of the Pi magazine - they are all available as PDFs from https://www.raspberrypi.org/magpi/issues/ and some can be purchased in paper format as well from the site. Have a flick through the beginners guide as the first one.

As for the programming side - I would say start with Scratch as this will teach you the basic of variables, loops and branches. It looks simple and maybe not fancy but its a great way to learn. Two magazines that are a good starting point are Issue 82 and the Boot of Scratch - do not worry about the childlike drawing (it annoys me) as the info is good :lol:

You will find lots of languages here but personally I find that Python is the most supported for devices attached to the Pi.

Just take your time (keep things simple to start with) and ask here when you get stuck.
One thing you may like to consider are the CamJam intro kits or the Breakout Garden. Both of these let you achieve things very quickly with only the basic of equipment.
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pcmanbob
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Re: Raspi pressure sensor

Sun Aug 11, 2019 1:11 pm

Hi.

If you want specific help with " these pressure sensors " then you need to tell us which pressure sensors you are talking about , post a link to the web site or data sheet for the devices you intend to use.

Remember we cant see your pi or anything connected to it so you need to provide as much information as possible for use to be able to help you.
We want information… information… information........................no information no help
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Kujoejoe
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Re: Raspi pressure sensor

Mon Aug 12, 2019 6:05 am

Thanks a ton AndyRoo you covered all the bases I couldn't have hoped for better.

Also pcmanbob I understand what you are saying and I'm sorry but I don't know what it's called frankly I don't even know if it exists I just imagined it up after seeing something kind of similar on a science project.
The idea is some sort of button that would react to Touch under silicone and then send some sort of signal up a wire to the Raspberry Pi that would be interpreted as a number or something like that.

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Gavinmc42
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Re: Raspi pressure sensor

Mon Aug 12, 2019 7:40 am

There is a bunch of methods that can do this.

Most are analog so need Analog to Digital Converters to interface to Pi's

Air pressure sensors, a tiny balloon is squeezed which changes the air pressure. or fluid.
Touch sensors capacitive or resistive like smart phone screens.
Membrane, like those flat membrane keyboards.
Force sensor, usually analog resitance changes.
Inductive sensors.
Hall effect that sense how close a magnet is getting.

Some guys here are playing with graphene based resistance ones.

What is the application?
Need to narrow it down some what.
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Raspberries are not Apples or Oranges

Kujoejoe
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Re: Raspi pressure sensor

Mon Aug 12, 2019 4:08 pm

The application is... let's go with robotic companions. Imagined up a new movement system for them that part's easy it's all this programming and silicone stuff that's becoming a pain in the butt.

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B.Goode
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Re: Raspi pressure sensor

Mon Aug 12, 2019 4:59 pm

Kujoejoe wrote:
Mon Aug 12, 2019 4:08 pm
The application is... let's go with robotic companions. Imagined up a new movement system for them that part's easy it's all this programming and silicone stuff that's becoming a pain in the butt.

Trying to keep this appropriate for a family-friendly environment...


Silicone is what you might use to impart some flexibility and touch responsiveness to some of the key areas of your 'robotic companion.'

The chips from which your RPi board is assembled to give you a product you can program are fabricated from silicon.

Kujoejoe
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Re: Raspi pressure sensor

Mon Aug 12, 2019 5:33 pm

Aye I'm trying to be careful about how I word this and still answer the question this seems to be the only site I can get any real help on so there's nowhere else for me to ask.

Andyroo
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Re: Raspi pressure sensor

Mon Aug 12, 2019 7:36 pm

There are two types of pressure sensors.

The first is to take the air pressure (one is in the breakout garden here)

The second is to record the pressure you apply (like a bathroom scale) such as this old article.

The common thing about all of these devices (and the majority of Pi bits) is that you have to make a program to read the data and display it. Often you can get a library from the manufacturer or previous user to do part of the job and you call those functions to do a lot of the leg work.

There are packages (e.g. Node-Red) that simplifies capturing and processing data but this is really ‘roll the sleeves up and get stuck in’ type of hobby :D

You can use Scratch to connect to some sensors (Dexter Industries make a kit) but it’s a lot simpler in Python.
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neilgl
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Re: Raspi pressure sensor

Mon Aug 12, 2019 9:01 pm

Is this related to the post “Raspi romantic chatbot”

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Gavinmc42
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Re: Raspi pressure sensor

Tue Aug 13, 2019 12:00 am

Some guys here are playing with graphene based resistance ones.
The application is for soft robotics.
There is a high demand for soft robotics in the care bot industry.
Tactile area array sensors need to be cheap and sensitive.

A google will find you lots of papers/info in this really new field of sensors.
I can tell you from my tiny experience these new graphene sensors are more sensitve than human touch with a wider dynamic range.

But for home hackers I'm have thought capacitvie touch sensor made with wovern stainless steel thread might work.
Should be less noticable in the furry pet type robots like Paro.
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

Kujoejoe
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Re: Raspi pressure sensor

Tue Aug 13, 2019 4:35 am

Thank you so much GavinMC42 really appreciate the info.

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Gavinmc42
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Re: Raspi pressure sensor

Tue Aug 13, 2019 6:07 am

TPU filament might allow for 3D printing shapes that a pcb made on flexible aramid might be sandwiched into.

Been lots of advances in Silicone softbotics molding but embedding wires is tricky.
I had thought of helical wiring so they can stretch as well as flex.
Ideally conductive silicone wirng embedded in non conductive silicone.
How do biological nerves work?
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

Kujoejoe
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Re: Raspi pressure sensor

Tue Aug 13, 2019 5:36 pm

I love Gavin the very kind of thinking is what presented my idea to move the robots. I've been on that line but frankly I was hoping I could find something simple that doesn't depend on my wiring ability. though I did previously install Invisible pet fences so maybe that tiny bit of nearly useless information will help me here...... I just realized I can probably very easily program a raspi to make my own pet fence monitor.

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Gavinmc42
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Re: Raspi pressure sensor

Wed Aug 14, 2019 4:45 am

These days it is very easy to self learn in any subject.
Pi's open up a whole world of stuff, not just coding, which I'm still learning too.

Visit the sensor sections of Adafruit, Sparkfun, Seeed Studio, Digikey, Element14, RS components etc.
So many types these days. There are even tutorials.

Back in the old days when I started I had to use velostat foam and two bits of foil.
Velostat was the antistatic black foam semiconductor chips had the legs stuck into so ESD did not kill them.
Plastics with high carbon contents can be a bit conductive, even those antistatic pink and blue bags can be a little conductive.

I did a google and there is now conductive silicone and even bio versions.
Not sure if there are 3D printers for silicone, if not someone should invent one :D
TPU is polyurethane rubber that is printable, is there a conductive version?
Dual print head 3D printer could make some interesting sensors.
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

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