Topics Topics Edit Profile Profile Help/Instructions Help Member List Member List  
Search Last 1|3|7 Days Search Search Tree View Tree View  

Data logger query

:: EPE Chat Zone ­:: ­Radio Bygones Message Board :: » EPE Forum Archives 2007-2009 » Archive through 11 October, 2009 » Data logger query « Previous Next »

  Thread Last Poster Posts Pages Last Post
  ClosedClosed: New threads not accepted on this page        

Author Message
Top of pagePrevious messageNext messageBottom of page Link to this message

muskrat
Frequent Contributor
Username: muskrat

Post Number: 65
Registered: 06-2009


Rating: N/A
Votes: 0 (Vote!)

Posted on Saturday, 19 September, 2009 - 02:32 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Does anyone know whether EPE published a design for a data logger?

I need one at the farm to monitor all my analogue probes and things.

Obviously, the unit would accept a number of analogue signals, digitise them, and squirt the readings to the PC for analysis.

Once again, I have to state that I do not have the necessary knowledge or expertise to design something like this, but am fully capable of building it.

My stuff is all PIC based, so I have all the necessary programmers etc. that are required for the Microchip products.

I know very little about this particular field, so, in advance, I apologise for the large number of seemingly insane questions that are bound to follow .......
Top of pagePrevious messageNext messageBottom of page Link to this message

dave_g
Frequent Contributor
Username: dave_g

Post Number: 570
Registered: 05-2005

Rating: N/A
Votes: 0 (Vote!)

Posted on Saturday, 19 September, 2009 - 03:45 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

The late John Becker did one, PIC based, a good few years back but I cannot remember which issue.
Top of pagePrevious messageNext messageBottom of page Link to this message

gajjer
Frequent Contributor
Username: gajjer

Post Number: 266
Registered: 05-2007

Rating: N/A
Votes: 0 (Vote!)

Posted on Saturday, 19 September, 2009 - 03:49 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi Muskrat
before we start you need to say how many channels you are monitoring. What sort of signals - temperature, soil resistance, light level etc. Are they changing rapidly or slowly? How many channels?

Should be a doddle to do it with a 16F871 if you don't need more than 8 channels.

cheers
gaj
Top of pagePrevious messageNext messageBottom of page Link to this message

bruce
Frequent Contributor
Username: bruce

Post Number: 180
Registered: 04-2008

Rating: N/A
Votes: 0 (Vote!)

Posted on Saturday, 19 September, 2009 - 04:21 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Well, if you want to do all that PIC programming and you need a continuous readout of several channels simultaneously, I cant help.
However, If you read IU in last months EPE you'll find a way of monitoring an analogue signal without the expense of a data-logger; it's a circuit I devised to check old SLAs for residual life, but can easily be adapted to anything you want. Plus, the circuit is dead simple. You could conceivably monitor several inputs just by using a muliplexer chip like the 74138. Basic stuff. Crude, but I bet you dont need the kind of precision you're going to get ( and pay for ) from a proper datalogger.

Bruce

John Becker's was 1999 I believe.
Top of pagePrevious messageNext messageBottom of page Link to this message

muskrat
Frequent Contributor
Username: muskrat

Post Number: 66
Registered: 06-2009


Rating: N/A
Votes: 0 (Vote!)

Posted on Saturday, 19 September, 2009 - 05:30 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Currently, I have 6 hydroponics tunnels, each split into 2 watering zones. In addition there are 6 open-field watering zones.

As far as plants are concerned, I'll need to monitor soil moisture level, TDS (Total Dissolved Salts) and pH. (18 channels per zone)

Environmentally, I would also require nutrient TDS and pH, ambient temperature, humidity and light level. (5 channels)

Ideally, all variables would be monitored and transmitted to the PC to analyse (Excel?)

I realise that there are a large amount of channels here. But if necessary, a suite of loggers could be built - environment, and one or two loggers per watering zone.

The signals are relatively slow moving, and would only require checking at 15 or 30 minute intervals.

If I have to use several logger devices - could they be connected together somehow to transmit their data along a single cable for reception by the PC?

A lot to ask I know. I don't even know whether this sort of thing is possible, but it would be of immeasurable benefit to the farm operations.

Most of the instrumentation has been built - all with a 0-5V signal output. It would be great to connect everything together and display trends etc in graph form. It would certainly reduce my habit of running around like a demented twit, getting progressively more hassled and producing increasing amounts of grey hair!

I should have known that John Becker would have played around with something like this. Is there ANYTHING that incredibly talented man could NOT do in the way of PIC stuff! He will forever remain a legend.
Top of pagePrevious messageNext messageBottom of page Link to this message

joe
:::: Super User ::::
Username: joe

Post Number: 642
Registered: 05-2005

Rating: 
Votes: 2 (Vote!)

Posted on Saturday, 19 September, 2009 - 06:06 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

oooo nice project.

I'd build one master recorder that has a buffer to record the data and then dump it to a PC on demand. This contains a PIC, RTC and battery backed RAM (I would use Microchips new Serial SRAMS - only need 4 lines to drive them and they are RAM not EEPROM so ideal).

You then create "nodes" that are strung out along a simple multi-drop serial bus and connect the sensors to the nodes.

Each node has an address and each sensor has a sub-address, that way the entire architecture is scalable.

Each node contains a PIC and using its internal A to D (or external if you prefer) you multiplex the analogue signals from your sensors to the input of the A to D.

You then send a command down the bus addressing each node in turn, within that command is a sub-address to select the correct sensor input.

All the nodes TX on the same wire via an NPN transistor and a single pull-up resistor back in the recorder, that way many nodes can sit on the same bus.

The recorder sends out a read command ie R0205 (Read Node 02, sensor 05). All nodes ignore the command except for node 2. If node 2 isn't there then you won’t get a response and after a time-out you know there’s a problem so the system has some fault-protection built in.

Since only the recorder requests data from the nodes you never get collisions on the serial bus. Its actually very simple to do; I've built entire distributed computers built on this technology and they work great.

The great thing about using serial is that at fairly slow speeds you can get fantastic distances and if needed; you don't give any indication of physical distances so if this was in my back garden, this would probably be a bit overkill :-)

You can also run the entire chain down 3 wires (TX, RX and 0v) tho you can also send +v as well to power the nodes and sensors. I'd send 12v and place a local 5v regulator in each node.

If you need any more details drop me a line and I'll draw some sketch’s for you.

Joe
Do one thing each day that scares you – work here !
Top of pagePrevious messageNext messageBottom of page Link to this message

gajjer
Frequent Contributor
Username: gajjer

Post Number: 267
Registered: 05-2007

Rating: N/A
Votes: 0 (Vote!)

Posted on Saturday, 19 September, 2009 - 06:16 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi Muskrat
the John Becker design was printed in Aug/Sept 1999.
Personally I think Joe's idea is probably more suited to what you are looking for. If you can do one design per zone its just step and repeat.


cheers
gaj
Top of pagePrevious messageNext messageBottom of page Link to this message

muskrat
Frequent Contributor
Username: muskrat

Post Number: 67
Registered: 06-2009


Rating: N/A
Votes: 0 (Vote!)

Posted on Saturday, 19 September, 2009 - 07:12 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Hi Joe.

What you have described seems to be ideal! Thank you.

The greatest distance (at present) will be about 100 metres. I have expansion plans which will ultimately give a max distance from control room to farthest zone of close to 1 kilometre.

I'll take you up on your offer, if you don't mind - I haven't a clue as to how to implement this sort of thing.

As Gajjer says - get one node working and the rest is easy.

Thanks again - an elegant solution, I feel!!!
Top of pagePrevious messageNext messageBottom of page Link to this message

arw
Board Administrator
Username: arw

Post Number: 780
Registered: 04-2005


Rating: N/A
Votes: 0 (Vote!)

Posted on Sunday, 20 September, 2009 - 10:43 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

I'd be interested to see this -- would you like to post a photo or two here of what you've been doing? (800 x 600 max per image).
Alan Winstanley

Visit EPE Online at http://www.epemag3.com
Top of pagePrevious messageNext messageBottom of page Link to this message

muskrat
Frequent Contributor
Username: muskrat

Post Number: 68
Registered: 06-2009


Rating: N/A
Votes: 0 (Vote!)

Posted on Monday, 21 September, 2009 - 12:50 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@arw
After many, many false starts and a steep learning curve trying to get to grips with the more technical aspects of hydroponics, I decided to develop my own instrumentation to assist in the management of the farm.

Although hydroponics has been a recognised cultivation method for many years, there are no definitive guidelines available. Everyone has their own methods and ideas. Me too! The equipment I've developed so far has cut our nutrient/water bill by 50%, has increased our yield from 1.2 tons/week to 4.3, and has my life a lot easier.

The images show a few of the working models. I don't have the courage to show the prototypes - they were total eye-sores!!

There is a level controller for the mixing tanks, a stand-alone moisture sensor, and the current sensor/feed timer unit.

Having gotten this far with the development, and having the sensors fully operations, I now want to get the entire farm connected up, hence the plea for help on the forum.

As always, when I have had a query or problem, the forum members are quick to help and offer support. The Chat-Zone is always my first port of call when I need a bit of help.

Hats off to all members!

The picture of the bare-board, by the way, is a prototype of a capacitive sensor to measure fluid level. It's essential to have some nutrient run out of the bag during the feeding cycle to ensure that there is no salts buildup. This gadget, while still being "tweaked" is working well, and I see it being used to measure fluid levels all over the farm - from the small run-off sensors to the 15 000 litre tank.

Thanks for your interest, and a huge thank you Joe for instantly understanding what I'm trying to achieve and for selflessly offering his help.


Hydroponics Instrumentation
Top of pagePrevious messageNext messageBottom of page Link to this message

arw
Board Administrator
Username: arw

Post Number: 781
Registered: 04-2005


Rating: N/A
Votes: 0 (Vote!)

Posted on Tuesday, 22 September, 2009 - 09:41 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

That's amazing -- if that sort of information isn't available elsewhere then why not write up a short PDF manual or e-book and upload it to www.lulu.com. The royalties might buy you a PICmicro or two...

I never cease to be amazed by the endeavours and resourcefulness of our readers.
Alan Winstanley

Visit EPE Online at http://www.epemag3.com
Top of pagePrevious messageNext messageBottom of page Link to this message

muskrat
Frequent Contributor
Username: muskrat

Post Number: 69
Registered: 06-2009


Rating: N/A
Votes: 0 (Vote!)

Posted on Tuesday, 22 September, 2009 - 10:55 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

Thanks Alan.
I must say that articles from EPE helped a great deal with the stuff I've put together. While it all works - and works well, the latest endeavour with Joe's expertise, is going to be a winner all the way.

The more information gathered from the plants themselves the more efficient the farm becomes. This has been my approach to the system - finding a way for the plants to let me know when they're "hungry", recognising over or under-watering conditions, and being able to recognise fault conditions with solenoid valves etc. The existing equipment, while a bit crude, have helped enormously. The plants now tell me what's going on in their environment, leading to a much more relaxed environment for all concerned.
Thanks again for the interest, and the comments. If the current project works out the way Joe and I envisage, we may well publish the results.

But that will be up to Joe as the primary designer here.
Top of pagePrevious messageNext messageBottom of page Link to this message

hackinblack
Frequent Contributor
Username: hackinblack

Post Number: 407
Registered: 09-2006

Rating: N/A
Votes: 0 (Vote!)

Posted on Saturday, 26 September, 2009 - 10:06 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

it doesnt really matter if the prototype is 'a mess';its only purpose is to prove the design can actually work;
a neat board which doesn't work wont teach you anything except how to tear your hair out

having priced up various pieces of greenhouse equipment,most of which where obviously way overpriced for the boxes contents,
the DIY way would seem to be the way to go;
only by completely understanding your own equipment can you,in a remote location,have a hope of keeping it going.
dead controls means dead crops.
the added bonus,apart from saving money is;the end result will be tailor-made for you,by you...

the inginuity being shown so many times on this forum is what is the lifeblood of modern electroncs,
the numbers may be falling,but the propagation(pardon the pun!)of ideas is accelerating

the front panels look good,by the way,if you are blundering;you are certainly blundering in the right direction
more importantly,when looked at from another angle;your increase in yield will more than pay for your developement time...
Top of pagePrevious messageNext messageBottom of page Link to this message

echase
Frequent Contributor
Username: echase

Post Number: 248
Registered: 07-2007

Rating: N/A
Votes: 0 (Vote!)

Posted on Sunday, 27 September, 2009 - 10:44 pm:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

If you look at this recent post http://www.chatzones.co.uk/discus/messages/7/9213.html?1252070325

there was a discussion there on data loggers. I have bought an ECIO (a 2550 PIC on a small pcb) with lots of analogue inputs and have acquired the software to write a datalogger programme. But it will take me some while to write it. It’s going to either be in Visual Basic or use a free version of LabVIEW. Glad of any help.

Did John’s article contain the software for the PC and is it still available for download?
Top of pagePrevious messageNext messageBottom of page Link to this message

muskrat
Frequent Contributor
Username: muskrat

Post Number: 71
Registered: 06-2009


Rating: N/A
Votes: 0 (Vote!)

Posted on Monday, 28 September, 2009 - 02:03 am:   Edit Post Delete Post Print Post    Move Post (Moderator/Admin Only)

@echase: I haven't gone further with John's article so can't answer your query about software. But knowing John's work, I'm sure everything would have been made available.

With Joe's help, we are putting together a new system that holds considerable promise.

Administration Administration Log Out Log Out   Previous Page Previous Page Next Page Next Page