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Today's Topics:
1. Re: Controlling valves (Matt Oates (Home))
2. Re: Controlling valves (Andrew)
3. Re: Controlling valves (Andrew)
4. Re: Controlling valves (Allen Coates)
5. Re: Controlling valves (John Daragon)
----------------------------------------------------------------------
Message: 1
Date: Thu, 26 Sep 2013 18:16:18 +0100
From: "Matt Oates (Home)" <mattoates@gmail.com>
To: andrew@1dtv.com, Bristol and Bath Linux User Group
<bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Controlling valves
Message-ID:
<CAAiD7uO83skG0Dz8Txh-r55jBpdwc1-23zL3Ghr1=18QPK_OEA@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Hi,
On 26 September 2013 15:36, Andrew <andrewsoltau@gmail.com> wrote:
> Any thoughts on pi vs arduino?
With the Pi someone said "port later to the Pi", it's just a Linux
desktop and you can run a relatively normal version of Debian on
there. If you are wanting to use C on the Pi I see nothing but
heartache with developing on PC then essentially reimplementing for
the Pi, with no upside. Just develop directly on the Pi if that's your
end goal. Oracle have even released a custom JVM that makes use of the
Pi's floating point hardware, since you mentioned Java programming.
I've been running a Minecraft server as a demo with reasonable
performance off of a Pi with the Oracle JVM. Personally I would use
Python as it's well supported with demo code and libraries for the Pi
including the GPIO pins. If all you are going to do is essentially
send the switch state to the valve why bother with mucking around in C
when it's a few lines of Python?
I'd personally use the Pi over an Arduino or anything fully embedded.
The Pi is cheap and does everything you need in a way that will be
familiar if you are a desktop developer. Any argument of whether you
need the computational power and if you should go Pi or Arduino... who
cares? If you have a real constraint like running off of a battery for
a decade then sure you want something lower power and fully embedded.
Arduino starter kits and a Pi cost about the same. If you suddenly
need more IO lines just get a multiplexer for the Pi, off the shelf
products like this exist already.
I'm going to throw out mbed (http://mbed.org) as another hobbyist
embedded option since you get quite a lot in a single package. The
mbed development process/environment is incredibly friendly to someone
new to embedded programming too.
Best,
Matt
------------------------------
Message: 2
Date: Thu, 26 Sep 2013 19:30:06 +0100
From: Andrew <andrewsoltau@gmail.com>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Controlling valves
Message-ID: <52447D2E.1090900@1dtv.com>
Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
On 26/09/13 16:29, Alaric Snell-Pym wrote:
> On 26/09/13 15:59, david wrote:
>
>>> Any thoughts on pi vs arduino?
>>>
>> Well I would go raspberry, because extra features might be handy one
>> day. Much easier to do remote control from your phone, and networking in
>> general. And I have found the i/o control easy to use from C.
>> But if it will always be a stand alone box, with simple push button
>> control then arduino is good and has lots of support for hardware projects.
>>
> I'd second that.
>
> 1) You'll be able to get going quicker on the arduino - less
> infrastructure. All the tools required to start waving I/O lines about
> are there in the standard setup.
>
> 2) Smaller, simpler, cheaper, lower-power device to put into your final
> project
>
> 3) Lots of easily accessible I/O lines, off the shelf "shields" to do
> stuff like driving relays or high-current driver transistors
>
> I assumed, with your talk of prototyping on a PC then using a Pi, you
> were going to be requiring beefy computer resources such as filesystem
> mass storage, networking, or video output - otherwise I'd have suggested
> the arduino too!
>
> ABS
>
Brill
Thanks
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Message: 3
Date: Thu, 26 Sep 2013 19:38:13 +0100
From: Andrew <andrewsoltau@gmail.com>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Controlling valves
Message-ID: <52447F15.1040300@1dtv.com>
Content-Type: text/plain; charset="utf-8"; Format="flowed"
On 26/09/13 15:59, david wrote:
> On 26/09/13 15:36, Andrew wrote:
>> Hi David
>>
>> On 26/09/13 15:21, david wrote:
>>> It depends on the scale, I am doing a lot of this commercially using
>>> Labview.
>>> That is a expensive National Instruments product.
>> Looking at their site this looks great.
>>> But some years ago they did give away a Linux version, which can still
>>> be downloaded from a German site. It is good and powerful, but has
>>> quite a learning curve.
>> That sounds ideal. But a bit of googling only turned up this forum post
>> which concluded there was nothing like that available:
>>
>> http://forums.ni.com/t5/LabVIEW/from-where-can-i-donwload-labview-for-Ubuntu-10-04/td-p/1250354
>>
>>
> http://forums.ni.com/t5/LabVIEW/labview-6-1-linux/td-p/1741200
> Says it is official, but only for home use in Germany, I would check
> the license on the download.
> ftp://ftp.heise.de/pub/ct/spezial/labviewlinux.zip? is working
Brilliant. I have downloaded it and will get to work.
>
>>> Labjack do some interface boxes with labview drivers for < ?100
>> That sounds just the job.
>>>
>>> However I would recommend starting on the Raspberry, looking at the
>>> home robotics shops, and use Python or any language you are happy with.
>>> David
>> Thanks
>>
>> Any thoughts on pi vs arduino?
>>
> Well I would go raspberry, because extra features might be handy one
> day. Much easier to do remote control from your phone, and networking
> in general. And I have found the i/o control easy to use from C.
> But if it will always be a stand alone box, with simple push button
> control then arduino is good and has lots of support for hardware
> projects.
Thanks for all this. Stand alone box is the objective. Given it is much
easier to set up, and my considerable inexperience, I think maybe it
makes sense to go for the arduino for the first cut; then if the project
requires more iterations I can graduate to raspberry. The big thing at
the outset is to get it working and try out the idea.
Andrew
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Message: 4
Date: Thu, 26 Sep 2013 20:06:45 +0100
From: Allen Coates <linux@cidercounty.org.uk>
To: andrew@1dtv.com, Bristol and Bath Linux User Group
<bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Controlling valves
Message-ID: <524485C5.3040601@cidercounty.org.uk>
Content-Type: text/plain; charset=ISO-8859-1
Hi Andrew
A project in the brand new "Raspberry Pi Geek" magazine uses an Arduino
flow meter; it monitors the RPM of an impeller in a short length of
pipe-work.
There are several other items about interfacing a Pi with the outside
world - you may find them useful.
If it is only "windscreen washer stuff", how about using an actual
windscreen washer pump with a relay-controlled 12 volt supply?
Just my two pence worth.
Allen C
Andrew wrote:
> Hi All
>
> I have been asked to do a project which involves using the pc to turn on
> and off some valves with reasonably accurate timing. I would be grateful
> if someone could point me in the right direction. I have done some
> googling but the subject seems to be massive and lots about robotics and
> nothing terribly simple. Terribly simple is what I am after!
>
> Firstly, what sort of software does one use for this? And where do I get
> the control valves - I assume I don't go to maplin, or is that the
> simplest way? Pressures are quite low, 10 psi or so, and the pipes will
> be quite small bore, like windscreen washer stuff. Might need to use a
> passed volume sensor / flow meter / however one does that.
>
> This would all get prototyped on a standard pc with Debian. The final
> objective is a using a raspberry pi with simple go buttons to set off
> different sequences of operations.
>
> Cheers
>
> Andrew
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Bristol mailing list
> Bristol@mailman.lug.org.uk
> https://mailman.lug.org.uk/mailman/listinfo/bristol
------------------------------
Message: 5
Date: Thu, 26 Sep 2013 17:43:05 -0400
From: John Daragon <john@blacklabs.co.uk>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>,
"andrew@1dtv.com" <andrew@1dtv.com>
Subject: Re: [bristol] Controlling valves
Message-ID:
<33F8E65C8ED54C4DA5074F1764532157D03F39D2CD@EXMBX01.njnx.lan>
Content-Type: text/plain; charset="iso-8859-1"
Sorry about top-posting - It's Outlook.
In this case, depending on flow rate, temperature &c, and the available power supply, I think you could do worse than :
http://www.ebay.co.uk/bhp/electric-water-valve
or
http://www.betavalve.com/plastic/appliance
You can get a solid-state mains relay for around a fiver.
I'd go for the RPi. Comms is easier, and if it's attached to a network, you'll always be able to work out what the time is. And it'll almost certainly be cheaper than using an *uino if you need Ethernet.
If you really want to use a PC, and yours is old enough, you can use some of the pins on the parallel port as surrogate GPIO pins:
http://as6edriver.sourceforge.net/Parallel-Port-Programming-HOWTO/parallel-port-programming-howto.html
If you have a spare serial port, you can use the handshake pins, too.
Pulsed flow-meter sensors rated at various temperatures and calibrated for various flow rates seem to be around for ~ ?15 a throw. Again, eBay is your friend. This is a bit more complex, as you'll need to write a little interrupt handler to count how many pulses you get in a unit time - unless you pass the responsibility for timing up the stack and just set your count to zero on open...
jd
-----Original Message-----
From: bristol-bounces@mailman.lug.org.uk [mailto:bristol-bounces@mailman.lug.org.uk] On Behalf Of Allen Coates
Sent: 26 September 2013 20:07
To: andrew@1dtv.com; Bristol and Bath Linux User Group
Subject: Re: [bristol] Controlling valves
Hi Andrew
A project in the brand new "Raspberry Pi Geek" magazine uses an Arduino flow meter; it monitors the RPM of an impeller in a short length of pipe-work.
There are several other items about interfacing a Pi with the outside world - you may find them useful.
If it is only "windscreen washer stuff", how about using an actual windscreen washer pump with a relay-controlled 12 volt supply?
Just my two pence worth.
Allen C
Andrew wrote:
> Hi All
>
> I have been asked to do a project which involves using the pc to turn
> on and off some valves with reasonably accurate timing. I would be
> grateful if someone could point me in the right direction. I have done
> some googling but the subject seems to be massive and lots about
> robotics and nothing terribly simple. Terribly simple is what I am after!
>
> Firstly, what sort of software does one use for this? And where do I
> get the control valves - I assume I don't go to maplin, or is that the
> simplest way? Pressures are quite low, 10 psi or so, and the pipes
> will be quite small bore, like windscreen washer stuff. Might need to
> use a passed volume sensor / flow meter / however one does that.
>
> This would all get prototyped on a standard pc with Debian. The final
> objective is a using a raspberry pi with simple go buttons to set off
> different sequences of operations.
>
> Cheers
>
> Andrew
>
>
> ----------------------------------------------------------------------
> --
>
> _______________________________________________
> Bristol mailing list
> Bristol@mailman.lug.org.uk
> https://mailman.lug.org.uk/mailman/listinfo/bristol
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End of Bristol Digest, Vol 518, Issue 6
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