Reef Discussion

[Rob]

The Raspberry PI is a $45.00 complete computer on a single board. It was released this year and is currently distributed through RS or Element14. The demand is soo high they are 100,000's in backlog.

I have been lucky enough get get my hands on one of these units.

Raspberry PI

Now what would you do with one. ?
Well if your into tank monitoring imagine having a complete web server and interface on one board. The raspberry PI will be the death of Arduino :) who's ability to serve web pages is very limited.

I already have a tank monitor running on a small server with trends reports alarms etc etc can be found here
rjconway.homeip.net Now imagine if I can move all this functionality on a small $45.00 embedded platform and all you need to do is connect it to the net and you can callup all the data and trends you like.

The plan:

Raspberry PI provides the web server, trending and interface to ph, orp and temperatures. The ph and orp is simply provided by a company called Atlas scientific who make small ph amplifiers that allow you to connect via a standard serial port to a device like the Raspberry pi. Difficult to visualize however this project will have limited soldering requirement plus the Raspberry pi uses a 4gb memory card card just slots into the unit. I already have developed the interface, gauges and trends so it "should" be simply.

Atlas PH and ORP Interfaces

All software is open source and totally flexible.

I will update the thread as I get the Raspberry PI up and running and then interface to the sensors. The PI could also control outputs very easily however this project will concentrate on monitoring only. A future addition may include cooling for evap fans.

Rob

 

[chimaera]

Very cool. Keep the updates coming.

 

[TJReid]

interesting, following along...

 

[macca_75]

Don't forget, x2 (where is that little poke emotion)


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[Rob]

Macca-75: The cool thing will be we just have to image the sdcard and you will be up and running. Maybe we need a coffee to go through the collective requirements. :)

This solution becomes an open linux environment and can scare some people, the amount of commands you need to know is very few. However once the packages are loaded it will just be a device on your network to upload web pages to etc etc so no linux knowledge really required. Raspberry PI group have some 101 style magazines available that step you through the hardware and potential applications.

Raspberry PI Magazine

 

[MagicJ]

Not sure it will be the death of the Arduino but it is an interesting little computer.

Look forward to further updates.

 

[macca_75]

Cmon Rob, 7 more posts to go.

 

[Rob]

Got the Raspberry PI running today, a standard Debian image on a 2 GB SD card with apache. I simply followed a couple of web links and it worked 1st go.

Now there is NO live data being monitored by the R PI at this stage however just copied my www directory from my Ubuntu server across to the R-pi.

Click the following two links to see the performance of the $45.00 800mhz R-PI ver a 2.4 GHZ dedicated Ubuntu server

UNbuntu server running a 2.4GHZ AMD 2 GB ram
Raspberry pi 800mhz 250MB Ram

The trends do not work on the R-PI as I have not had a chance, however you can see the entire web site does load OK. As I'm within my own network I don't really know the speed difference between the two servers. Someone might like to comment on speed of loading each of the sites.

Next step is to get live data being monitored and get the trending functional.

This is the basic overview

 

[DavidS]

Both load speeds appear about the same which isn't surprising. You'll be far more limited by bandwidth (and possibly your routers port forwarding abilities) than grunt. Get a stack of people hitting the Pi while it's working and other I/O factors might start dragging her down though. Apache has been run with a lot more traffic on a lot slower hardware than a Raspberry Pi :) Not sure it has 250GB RAM though :)

Watching this one with interest. Starting to sound like something I want to build... as long as I don't have to code.. I hate programming lol.

 

[macca_75]

As great as a web site might be with fish tank params 5we all love it) I can't see the world wide demand being such that the level of traffic becomes a concern. Most traffic I can think of generating is putting a small pic in you signature that has the params and refreshes every time someone hits one of your posts (similar to the reefangel).

That would be a great way of monitoring your tank as we check this forum daily :-)


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[Rob]

Macca, Like the idea of generating an image within the signature. I did use this technique early on to generate some data on a static graphic.
If I did create a image (jpg) any idea on how to stop the client from caching the image ?

 

[Rob]

Its been a month however made some progress.

HARDWARE
Have been waiting on a breakout board to mount the connectors and components. I found a breakout board from RK education that was perfect. Allowed me to mount two 1wire adapters and a serial MUX.

This board allows
3 x serial ports ( connection of pH, orp and FLO-30 from Atlas scientific)
2 x 1wire adapters (allows two different 1wire buses that could potentially connect 50+ 1wire devices
4 x digital output that will direct connect to a relay board by Futurelec.

OK here is a pic of the raspberry pi connected up to the breakout board. the breakout board may look compicated however its just a set of power regulators at the top portion.

SOFTWARE
I have 1wire communications established to a few temperature probes.
I have proved that I can communicate to the Ph and orp devices and they return data values.

I now have load and configure a web site and trends to show the data. This is simply from my existing site so should not be too much drama.

Rob

 

[Rob]

BREAKOUT BOARD
The breakout board I used has a lot of power regulators included, 3.3V, 5V and adj. I do not think I will need any of these due to the design and low power requirements for monitoring. So I plan on using a newer breakout board, half the size and only have a 3 components and the connectors, 1 x 74HC4052 (Serial MUX) and 1 x DS2482-100 (1wire drivers) and a I2C isolator (converts 3.3 to 5V).

 

[bug]

YOU SIR ARE MY HERO!
i've been waiting for someone to do this!!:D

 

[Rob]

A great thing with Raspberry PI is that you can image the sdcard and share the install between people very easily.

This is the new breakout board I plan on testing http://www.rkeducation.co.uk/RKSxb-mdc.php It has two locations for the 1wire interface chips. Its on its way at the moment so give me a couple of weeks and I will post back the results and if I can fit all the connectors on.

 

[macca_75]

You know I'm watching this

 

[Synodontis]

You know I'm watching this

I think a lot are macca_75 lol. :) Looks very cool.

 

[Rob]

Looking for a web guy. on the forum who is associated with web page design. I would kind of like some help in creating some web pages for the display of data. I have the pieces in place for trending and gauges (html 4) that my current site runs however getting some other views on data representation would be good.

I would like to create a couple of standard pages to display the data for both PC based plus get different pages to be loaded when served to IOS Ipad/Iphone. if I can get some help we could get a standard interface and create a signature banner as well. The Raspberry PI runs apache so anythinf in theory should be possible, I have the data collection stuff already done.

 

[MagicJ]

Rob, daveH may be able to provide some assistance (hope you don't mind me dobbing you in :))

 

[daveH]

Rob, shoot me a bit more info on what you're wanting. I might be able to help.