Any electronics Gurus Please

[Shawn]

Its a project,,, aka invention, for part of it I need a pressure switch, with fuzzy logic.. all it needs to do is open and close an air valve via soleniod, BUT... It needs to know when the pressure has stopped increasing.. sampling times and pressure value must both be adjustable... Anybody up to it...

Oh low current draw , must run off small PV panel...

Anyone help with this... ?

Shawn

[acropolite]

Shawn I suspect more information is required, what sort of pressure switch, hydraulic, air pressure, low or high pressure water?? BTW your link doesn't work, I suggest you just upload the image.

[Shawn]

sorry about that, It was a copy and paste... looked great on the clip board...:D..

Anyways its air pressure, the sort of pressure you may achieve if you leave a 20 litre empty jerry painted black in the sunshine, from there down to about what 800 hpa ?...

It needs to sample pressure "sample time adjustable", and based on a no change scenario in "x" seconds release the pressure, hold open for a predetermined time, then close.

Does that help...:shrug:

[Starkler]

Sounds like a job for an industrial programmable device like a PLC or RTU.. ie not a cheap item.

It may be possible to build a dedicated device based on a PIC microcontroller, but if you want someone to design and build one for you its not a trivial ask :whistle:
Whats the budget for this?

P.S. I have built monitoring/control setups around kingfisher RTU's, but not PIC or PLC so I cant help with this.

[Shawn]

Hi Geoff

No probably not trivial, but .. If it makes you wealthy, whilst helping others.. Its worth it...Anyone that has the knowledge to do this...PM or Email..

Appreciated...

Shawn

[Starkler]

This device will do it and I know how to program them. Its a very flexible low power device and will even take care of battery charging from solar cells.

http://www.rtunet.com/products/low-power-rtu/lp%111-low-power-rtu/details/

The question is how much did you figure to spend? A rough guess without asking prices has me guessing a ballpark of around 2-3k.

[Shawn]

Geoff

I want to build a prototype, well a proper one anyway, as I said it works If I play the the part of the fuzzy logic controller, the cost of the prototype should be minimal, and the finished item should be able to be mass produced for a few hundred. It needs to use the KISS principal, "Keep It Simple Stupid" :lol:. Now if it helps.. The device has a bleed off on the pressure cycle, which could be used to determine "end of expansion", this may make the unit cheaper to build. In terms of not needing a pressure sensor as such.My target market is 3rd World and extreme rural, And No I would prefer not to spend anything on the developement of the electronic side of the project, but rather find a partner that wishes to come on board, help with developement, iron out the wrinkles, built the prototype and approach a developement finance outfit... Its going to cost me personally quite a bit to build the mechanical side of the device, money I dont have. But so supremely confident that there is a marketable result, Im going to do it anyway...:D.

Shawn

[GrahamL]

Shawn you should give the QIT a call and talk to someone in there R &D
arm , they used to have development funding that allowed worthwhile
ideas to attract some govt backing .:)

[acropolite]

Jaycar have some electronic pressure sensors, and Silicon ship have published at least one project (http://www.siliconchip.com.au/cms/search/index.html?scope=&keywords=water+tank+level)using that sensor to measure water tank levels. From memory, they used a PIC processor. That article may be a starting point, then you either need to teach yourself how to program PIC's or find someone who can do it for you. The electronics described have a relay output to start a pump at a preset low pressure (the opposite to what you want), so that would fit with your need to open a solenoid valve, provided the sensor is capabe of measuring the pressure range you require, changing the PIC programming shouldn't be that daunting a task.

[MrB]

Been programming PIC's for something like 15 years, but sorry, I don't have the time to do this.

If however you are unable to find someone to help and decide to do it yourself, learning to program PIC's(or any micro) is not as simple as it would seem as there are lots of undocumented 'Gotyas' and it's not simply a matter of programming as you need a pretty good understanding of electronics too.
I'm still learning!

So, I recommend a PICAXE controller.
While it's still a PIC, they are slightly different in that they are preprogrammed with an interpreter, they are then easily programmed with flowcharts or a BASIC like language, even reasonably complex tasks(yours appears to be fairly simple) can be done with just a few lines of code.
The PICAXE's are so easy to use that they are used by students in primary and secondary schools all over the world.
Almost all of the Silicon Chip projects that use a micro, use a PICAXE.
They are also powerful enough to be used in serious apps... you know the Holden Efijy concept car?.... Yep!

There's probably a hundred places you can buy them in Australia, shop around. There's a massive amount of information about them so Google is your friend.
The homepage is:www.picaxe.co.uk (http://www.picaxe.co.uk)

No affiliation etc etc.... infact, I've only ever used a PICAXE once because they do have limitations.

[Shawn]

I might try that, and thankyou gents for the links and ideas...

Shawn

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