All times are UTC + 8 hours




Post new topic Reply to topic  [ 120 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6, 7, 8  Next
Author Message
PostPosted: May 10th, '13, 21:19 
Offline
Xtreme Contributor
Xtreme Contributor

Joined: Feb 27th, '13, 22:53
Posts: 187
Gender: Male
Are you human?: Often
Location: London, UK
bcotton wrote:
first off the people suggesting you would put cpanel or webmin on a raspberry pi are just being argumentative, and no, they arent sufficient ways to manage a server.


Hey, nobody suggested installing cpanel or webmin on the pi. :naughty: It was just an example (and there are countless others, webmin being a better one) of adminstration interfaces written in php.

It was misleading to say LAMP "...will be your application and the way you automatically collect and report information". mdavid's just given a great example of getting a very useful application running with a few lines of shell script over ssh.

_________________
My outdoor IBC system.

My indoor aquarium system.


Top
 Profile  
Reply with quote  
    Advertisement
 
PostPosted: May 10th, '13, 21:31 
Offline
Xtreme Contributor
Xtreme Contributor

Joined: Feb 27th, '13, 22:53
Posts: 187
Gender: Male
Are you human?: Often
Location: London, UK
bcotton wrote:
when you query a usb or serial temperature sensor you are most likely going to be querying the software that comes with the device.


The (commonly used) ds18b20 probes don't need (or come with) software, you just insert a kernel module and read from a file. Really not that different to reading the internal temperature of the pi.

http://learn.adafruit.com/adafruits-ras ... ng/ds18b20

_________________
My outdoor IBC system.

My indoor aquarium system.


Top
 Profile  
Reply with quote  
PostPosted: May 11th, '13, 01:25 
Offline
Legend Member
Legend Member

Joined: Aug 14th, '10, 03:55
Posts: 530
Gender: Male
Are you human?: Jar Head Clan
Location: Minnesota, USA
In the long run I like the one wire sensors concept but have questions. If I'm successful and comfortable, I'll add multiple one wire sensors as the CFO and finances permit.

For now I'm looking at a minimum of 3 waterproof temperature sensors.

One sensor for outside air temperature, one for greenhouse air temperature and at least one for fish tank temperature.

So I'm wondering how to string the "buss" wire. I'll probably use Cat5 for convenience sake. Right now I'm thinking the outside sensor is one direction from the Pi ( which is in the house) . The other sensors are a different direction from the Pi. So the "buss wire" will look like a "star" network configuration to the Pi.

Is that do able?

How many "legs" of the "star" are possible if any ?

How long can the "legs" be? Do the ends of the "buss" wires have to have termination of some kind or can they just end with a one wire sensor?

How are folks doing their multiple one wire sensors?

_________________
Remodeled Kitchen System

Raspberry Pi

Strawberries in Minnesota

Sprouting Grains


Top
 Profile  
Reply with quote  
PostPosted: May 12th, '13, 07:16 
Offline

Joined: May 12th, '13, 06:57
Posts: 4
Gender: Male
Are you human?: yes
Location: Perth
Hi Bob,

I've been looking at doing something similar... Currently I have a Raspberry Pi with an Arduino UNO connected. I had some issues initially with getting the Arduino IDE to run on the Raspberry PI.

I don't have a monitor or keyboard connected, I just remote desktop in. My plan is to have to UNO read things like PH and temps. Also to control when the backup pump comes on.

I haven't got very far on the Arduino side but have got afew things running on the PI that might interest you.

This is where I started.

http://n00blab.com/how-to-set-up-raspberry-pi-without-monitor/

Then installed something called "Cacti", which can display collected data such as temps (currently only have the internal temp of the Pi displaying.

http://n00blab.com/cacti-pi/

and this:

http://n00blab.com/correcting-cacti-timezone/

As this was all very new to me and followed the guides mindlessly I did have some issues with group settings that I had some help with.

I also have a PH probe and sheild that seems to work but I haven't got the calibration solution yet.

https://www.tindie.com/products/rezahussain/arduino-ph-shield-by-dormant-labs/

After buying my Arduino I found a possible alternative for field devices..

http://www.phidgets.com/index.php

Ahh also some other devices like flow meters:

http://www.seeedstudio.com/depot/sensors-gas-and-liquid-c-144_151.html
https://www.sparkfun.com/categories/23


Cheers,
Stu


Top
 Profile  
Reply with quote  
PostPosted: May 12th, '13, 22:09 
Offline
Newbie
Newbie

Joined: Jan 13th, '13, 09:58
Posts: 15
Gender: Male
Are you human?: yes
Location: High Springs, FL
You can add multiple 18B20's to the same data pin...I'm using GPIO 4. You only need one 4.7K resistor for the group.


Top
 Profile  
Reply with quote  
PostPosted: May 12th, '13, 22:30 
Offline
Seriously, this cant be healthy.
Seriously, this cant be healthy.
User avatar

Joined: Mar 26th, '10, 20:46
Posts: 5276
Location: South Australia
Gender: Male
Are you human?: Yep
Location: South Australia
apnea, that seeedstudio site rocks

There's some very cool stuff there.

Like this for instance

2KM Long Range RF link kits $14.50

very cool.

_________________
-

My system

120 THINGS IN 20 YEARS - My blog about my learning adventure

My skills include being able to move slowly forward in time, and if I really concentrate, I can sometimes tell what I'm thinking.


Top
 Profile  
Reply with quote  
PostPosted: May 12th, '13, 22:54 
Offline
Xtreme Contributor
Xtreme Contributor

Joined: Feb 27th, '13, 22:53
Posts: 187
Gender: Male
Are you human?: Often
Location: London, UK
Bob H wrote:
So the "buss wire" will look like a "star" network configuration to the Pi.

Is that do able?

How many "legs" of the "star" are possible if any ?


You probably read this already, but the FAQ has this to say:
Quote:
In a star topology the 1-Wire bus is split at or
near the master end and extends in multiple
branches of varying lengths, typically with
slave devices along or at the ends of the
branches. Since each branch has its own
characteristics reflection it once again becomes
difficult to control reflections and signal
cancellations. Do not build this sort of
network


I read somewhere else saying that in practice it can work though - but ymmv.

The faq goes on to recommend "using a device such as the DS2409
MicroLAN Coupler16 a 1-wire hub device, at the branch point".

_________________
My outdoor IBC system.

My indoor aquarium system.


Top
 Profile  
Reply with quote  
PostPosted: May 13th, '13, 08:39 
Offline
Xtreme Contributor
Xtreme Contributor

Joined: Feb 27th, '13, 22:53
Posts: 187
Gender: Male
Are you human?: Often
Location: London, UK
So I finally got round to playing with my pi. And here are my results!

Attachment:
File comment: Screen shot
Screen Shot 2013-05-13 at 01.42.56.png
Screen Shot 2013-05-13 at 01.42.56.png [ 204.85 KiB | Viewed 4184 times ]


So far it's just two temperature sensors, but I'm pretty happy. I've attached them directly to the pi for now, but will probably introduce an arduino at some point and use it's ADC to measure some analogue sensors (yeah, I could just buy an adc but I already have a couple of arduinos).

I've also ordered a web cam, so that might be next on the list of things to try out. The only posts I've seen with video so far have been mjpeg; not great but that would do for me.

I've also added my name to the 'interested' list for the camera module, it's due to be released any time now, perhaps some tutorials on how to achieve better quality streaming video will come with the new module?

I've got light sensors (are the lights on), pressure sensors (to measure the depth of water in the tank) and a flow meter (is the pump working) still to play with. I've also got some relays (mechanical and solid state) so I might give pump and light control to the pi.

I'd really love to be able to measure some water parameters... (ph, DO etc). If anyone has any joy do report back!

[Edit: added screen shot, in case the site goes offline or something]

_________________
My outdoor IBC system.

My indoor aquarium system.


Top
 Profile  
Reply with quote  
PostPosted: May 13th, '13, 13:20 
Offline
Seriously, this cant be healthy.
Seriously, this cant be healthy.
User avatar

Joined: Mar 26th, '10, 20:46
Posts: 5276
Location: South Australia
Gender: Male
Are you human?: Yep
Location: South Australia
Pressure for water depth. For some reason, I've never considered that angle to check for water depth.

Good brain using!

_________________
-

My system

120 THINGS IN 20 YEARS - My blog about my learning adventure

My skills include being able to move slowly forward in time, and if I really concentrate, I can sometimes tell what I'm thinking.


Top
 Profile  
Reply with quote  
PostPosted: May 13th, '13, 13:24 
Offline
In need of a life
In need of a life
User avatar

Joined: Aug 21st, '12, 15:28
Posts: 1601
Location: At my desk
Gender: Male
Are you human?: YES
Location: Coolbellup
Will it need an external atmospheric calibration measurement? This site suggests that 10cm of water gives 1.00992 ATM. i.e. 1% change - which is in the range of atmospheric variations.

http://www.calctool.org/CALC/other/games/depth_press

_________________
Frontyard systems: viewtopic.php?f=18&t=15937
backyard system: viewtopic.php?f=18&t=16873
Duckyard system: TBA


Top
 Profile  
Reply with quote  
PostPosted: May 13th, '13, 13:50 
Offline
Legend Member
Legend Member
User avatar

Joined: Jun 21st, '12, 06:51
Posts: 545
Gender: Male
Are you human?: YES
Location: Australia, WA, Beldon
I've seen water pressure sensors that do so with an externally compensated air pressure sensor (so one side of the diaphragm is open to the atmosphere).

It's really clever how they do it, you just attach one side of the pressure sensor to the underside of a PVC endcap, and attach 1.5 metres or so of PVC to it. Then put the PVC pipe vertically in the water.

As the pipe is filled with air you end up with knowing the pressure of the water at the bottom of the water, while keeping your pressure sensor dry... Genius!

_________________
My system
My solar upgrade
My wicking beds
My chooks


Top
 Profile  
Reply with quote  
PostPosted: May 13th, '13, 16:11 
Offline
A posting God
A posting God
User avatar

Joined: Dec 10th, '11, 15:03
Posts: 2089
Gender: Male
Are you human?: What is human?
Location: Perth Hills
If you had to purchase a sensir , surely a ping sensor would be easier?

I got very reliable readings from mine with 5 ping average....

Sent from my GT-I9300 using Tapatalk 2

_________________
Aquarium System
IBC System
Blog


Top
 Profile  
Reply with quote  
PostPosted: May 13th, '13, 16:48 
Offline
Xtreme Contributor
Xtreme Contributor

Joined: Feb 27th, '13, 22:53
Posts: 187
Gender: Male
Are you human?: Often
Location: London, UK
BullwinkleII wrote:
Pressure for water depth. For some reason, I've never considered that angle to check for water depth.

Good brain using!


Thanks, but it's not my idea! It's a common method in homebrewing circles. The only issue they seem to have is that the air tube can fill with water, so most people attach a 'bubbler'. I figured this wouldn't be a problem since I'll have an air pump running anyway.

rsevs3 wrote:
If you had to purchase a sensir , surely a ping sensor would be easier?

I got very reliable readings from mine with 5 ping average....


You mean something like this?
Attachment:
File comment: HC-SR04
distance_sensor.png
distance_sensor.png [ 62.69 KiB | Viewed 4153 times ]


Gosh, they are cheap! at that price I've ordered a couple and will try them out at some point. Glad to hear you've had good experiences with these types of sensor.

My main concern is weatherproofing it. I imagine even in an indoor set up it'll be exposed to high humity and some splashes. For my outdoor system it's got the weather to contend with too. At that price it's worth experimenting with though!

nebbian wrote:
I've seen water pressure sensors that do so with an externally compensated air pressure sensor (so one side of the diaphragm is open to the atmosphere).


Exactly! I went for an MPX5010DP (for roughly £9 each) as this is what most people use with the brewtroller (linked above). They come in all sorts of varieties, but this one is designed for differential pressure - leaving one end open to the atmosphere gives the type of reading you want for this sort of measurement.

The range is over about 1m depth, but I'm not sure if the resolution is going to be enough to get sensible data from a tank though - there are other models that will measure smaller depths but at higer resolution which might be more suitable for (basically) constant height tanks.

Now just to find some time to try them out...

_________________
My outdoor IBC system.

My indoor aquarium system.


Top
 Profile  
Reply with quote  
PostPosted: May 13th, '13, 17:38 
Offline
Seriously, this cant be healthy.
Seriously, this cant be healthy.
User avatar

Joined: Mar 26th, '10, 20:46
Posts: 5276
Location: South Australia
Gender: Male
Are you human?: Yep
Location: South Australia
Resistance would be a pretty easy level checker as well. A stainless steel earth wire running the full depth of the tank, then a series of progressively shorter ones each connected to a pic pin. 100% resistance = no water at that level.

_________________
-

My system

120 THINGS IN 20 YEARS - My blog about my learning adventure

My skills include being able to move slowly forward in time, and if I really concentrate, I can sometimes tell what I'm thinking.


Top
 Profile  
Reply with quote  
PostPosted: May 13th, '13, 17:50 
Offline
A posting God
A posting God
User avatar

Joined: Dec 10th, '11, 15:03
Posts: 2089
Gender: Male
Are you human?: What is human?
Location: Perth Hills
BoredomIsFailure wrote:
Thanks, but it's not my idea! It's a common method in homebrewing circles. The only issue they seem to have is that the air tube can fill with water, so most people attach a 'bubbler'. I figured this wouldn't be a problem since I'll have an air pump running anyway.


Actually it is quite common in industry everywhere. We have a few DP cells here at work.

BW, i have thought about a few different ways using that kind of idea, or capacitance etc. The only problem i can think if is having biofilm growing on everything that is submerged messing with the reading :dontknow:

_________________
Aquarium System
IBC System
Blog


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 120 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6, 7, 8  Next

All times are UTC + 8 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

Powered by phpBB® Forum Software © phpBB Group
Portal by phpBB3 Portal © phpBB Türkiye
[ Time : 0.198s | 18 Queries | GZIP : Off ]