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Forum Index : Other Stuff : Data Logger
| Author | Message | ||||
| BjBlaster Regular Member  Joined: 04/04/2008 Location: AustraliaPosts: 55 |
Hi Guys, Has anyone got a good (and cheap) expandable data logger of some sort? I love the piclog, but I want something I can expand and measure my solar / heating / wind / currents in loads etc and either push it straight down ethernet to a web/ftp server locally to store it, or something that has flash memory and can store this data onboard to pull later. I was looking at using the 1 wire sensors, but something pic based with lm35 temp sensors and the like would be fine. This way I can host up my live RE stats on my web site! Ideas? Bj Check out my projects here in: Bj's Shed |
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Gill Senior Member  Joined: 11/11/2006 Location: AustraliaPosts: 669 |
Bj, Why don't you make your own? I modified Glenn's Charger project to give me Amp readings of Solar, Wind, Hydro, Total A generated, Load, Dump and Battery charge. These readings were sent via either radio link or wire link to the PC for logging. The IC used was a Picaxe 28x1 but this also drove an LCD so a smaller chip may suit your application better. Adding a temp sensor is no dramas as it is well covered in the Picaxe manuals. I think some of the software mentioned in the Data Logger project is capable of providing continuous data to up-link to a web site, but that is not my interest so I've not looked into it. No one is offended if you use the guts of one of this sites picaxe projects and modify it to your own windmill data needs. The input circuits are already there, so to are the code samples for sending data to PC. I don't think you'd get a tailored data system any cheaper. was working fine... til the smoke got out. Cheers Gill _Cairns, FNQ |
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GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Bj, The Maxim DS2450S is a useful device. 4channel 16bitADC. Hook 3 up to a picaxe08M and some simple code and you have at least a 12 channel, 16bitADC voltage input sensor. This is not a logger though. The common earthing will still present some issues. I am still working on my own logger. Opto coupled analogue to digital converters on many sensed inputs is tricky. I will still be using the VB application I published a while back. The web interface is not where I would be heading either. I have to settle on a modular system that has high or low gain inputs, for current and voltage sensing, with the opto coupling. I don't want to record data with measument errors from ground loop interactions. I have tried hall effect devices, but I am still considering sensing resistors for current. Good luck with your logging project. Gordon. become more energy aware |
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| BjBlaster Regular Member Joined: 04/04/2008 Location: AustraliaPosts: 55 |
I was prepared to, but it's always good to ask first just in case you don't have to re-invent and then inflate the wheel :) I have a linux server that runs all day, so I'll probably just whip up some app for that and use a pic / serial port job. I do like the 1 wire, but if no-one has tried it then it's best to KISS. Cheers Bj Check out my projects here in: Bj's Shed |
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| BjBlaster Regular Member Joined: 04/04/2008 Location: AustraliaPosts: 55 |
For current measurement, what about something like these little fellas? from RS - LEM LTS25-NP as they only need a 5V single rail supply. Anyone tried something like these in their projects for PIC current interfacing? Check out my projects here in: Bj's Shed |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Bj, these transducers have relatively low gain [max +/-0.6V swing] and high current [>20mA] consumption. You would probably need to use 16bitADC and only powerup device during measurements. Gordon. become more energy aware |
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| BjBlaster Regular Member Joined: 04/04/2008 Location: AustraliaPosts: 55 |
Ended up building a "rs232 bus" that can handle multiple picaxe 08Ms. I can then have 2 analogue inputs per picaxe. This has worked out really well, as the scattered around my house measuring temp and solar volts at the moment. I used some spare ports on my existing cat5 network around the house, so each picaxe is powered from the rs232 hub and TX/RX is all done over the 4 pairs. I then used my mythtv box to run the linux software that asks each pic for it's data and logs it. The roof temp also turns on an roof extraction fan after 30oC. Here is the live data here that is updated ever minute if there is a change. Still have a bit to go getting the graphs and history working under perl, but it's a start :) Cheers Bj Check out my projects here in: Bj's Shed |
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| mattvenn Newbie  Joined: 31/03/2009 Location: Posts: 22 |
I used zetex 1022 current sensors with 5mOhm shunt resistors. These give a voltage swing that is easy to read with an ADC. |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
I think the Zetex are designed for 12V applications. become more energy aware |
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KarlJ Guru  Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
simple and relatavely cheap, I bought a APRS world anemometer and logger, logger does heaps of things and dumps it to an SD card. so far the only problem is I need a tower for the anemometer that would be the same height as the turbine (per a book I just read, relatively low level, 2m above house mounted to chimney) is pretty useless. Incidentally on / around black saturday we recorded 50deg+ on the temp sensor and max windspeed of 15m/second! we were inside watching the garden die before our eyes...... Luck favours the well prepared |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Karl, the 200+EURO price may put a lot of people off. Gordon. become more energy aware |
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