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08/09/2006, 09:38 AM | #76 |
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I don't see why the vernier probe amplifier wouldn't work. It puts out 0-5 volts that should be readable by any daq device. I might order one for orp, unless I see something better on ebay in the next few months.
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08/22/2006, 09:22 PM | #77 |
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Hrm, thread dieing...
Not being a hardware/software expert... I see lots of X10 pH probes on google, I know it's not 1-wire, but as X10's already been added to the WRRC project, wouldn't it be relatively easy to use an X10 pH probe? Other option - I notice many of the handheld pH probes for scientific use have a RS232 port - the linksys routers can have an RS232 port added quite easily... Is that a better option? Andy |
08/22/2006, 09:35 PM | #78 |
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??? What? X10 pH probe? I looked around google for a minute can't find what your talking about, but I am seriously interested to know because this would solve a lot of my problems. Are you sure your reading the pages right? Could you be looking at a Attenuation Ratio that is x10(times ten) or the resolution?
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08/22/2006, 09:53 PM | #79 |
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Ok, you're right it would seem I'm loosing it tonight... Now I can't spot em - could have sworn I did on some pool related websites...
However: http://www.drdaq.com/ph.html This could be adapted and drivers are available for linux... May require one of the newer routers - as you'd need to probably use one of the usb->parallel adapters - which is workable under linux it seems. |
08/22/2006, 10:34 PM | #80 |
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This Dr. Daq stuff is that using standard temp and pH probes? I have looked into them a little before. What ever I get I want to make sure that future upgrades and applications don't send me to buying every single piece over again unless I can get one thing working 100% well doing everything.(because then of course I wouldn't care, but that is not going to happen)
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08/22/2006, 10:48 PM | #81 |
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Sounds like the pH probe is an 'off the shelf' probe. The temp sensor - they note they include details to use 3rd party sensor, looks like it's off the shelf with the exception of the phone jack connector (I could be wrong, but temp probes are reasonably cheap...)
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08/23/2006, 08:31 AM | #82 |
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I thought the DrDAQ module looked familiar! Here is a web page for Doctor Aquarium , aquarium software based on the DrDAQ module. It requires a PC, of course...
dave |
08/23/2006, 12:56 PM | #83 |
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Doctor Aquarium looks sweet. I have DLed the software and plan on playing with it soon. I also e-mailed them with several different questions. I would like to be able to do everything from my PC that way I can easily upload everything to my site and edit it all over anywhere. I do not have a house phone line only a cell and a cable modem, so most normal devices will not work. The router idea seems to be a bit over my head, but I'm trying to follow as closely as I can and get ideas for my application where ever possible.
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08/23/2006, 05:47 PM | #84 |
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Well, that's the point of the router - it takes the place of a PC running linux. Some things aren't going to be possible, as RAM and drive space is somewhat limited (except on some of the newer USB equiped routers, where you could add a USB drive). But the basics of a reef controller are definitely possible.
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08/23/2006, 07:26 PM | #85 |
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I've got 6 old PCs laying around that could probably run linux. People just throw out old computers all the time. I think it would be cheaper to get a computer then a router. There is a reason I changed out of the comp sci major, lol. Programming isn't for me, but I wish everyone best of luck. If someone does manage to get it together make sure to document exactly how it was done. I've just been hoping to leak knowledge from the brains working on this. If they can accomplish it on a router a PC should be easy.
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08/24/2006, 02:36 PM | #86 |
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The reason to use a router is because its a tiny platform. PC would be fine if you had plenty of space close to you tank. I like the router cause I could mount it higher then the tank and keep it safe from spills. With its size it still would be unobtrusive.
Rick |
08/24/2006, 02:42 PM | #87 |
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Gumstix would be cool to use too. Not sure if they would work though.
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09/02/2006, 05:02 PM | #88 |
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I've been lurking a bit and looking to adapt the pH for use with my home automation box which already has a 1-wire network. I tried out the MAX406 method and can get a fairly constant mv reading thru a multimeter. I see one of the ideas was to use the HVAC monitor from HobbyBoards that has a DS2450 on it. Problem is for the life of me I can't get the DS2450 to see the output from the MAX406 circuit. Has anyone tried this?
Thanks! -Mike |
09/02/2006, 06:26 PM | #89 |
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The HVAC monitor from HobbyBoards is built to monitor for 28v. I don't know anything about the MAX 406 op-amp. I use a PHMA ph transmitter (eBay for $30) with the HVAC monitor from HobbyBoards (next time I'll make one myself). The HVAC monitor must be modified to be able to read the 0-5v from the ph transmitter. When I ordered mine from HobbyBoards, I told them I needed it to read 0-5v instead. They shipped me one with most of the resisters, caps, and diodes removed. The screw terminals are wired directly to the DS2450. I then use a 12v switching power supply with a resistor wired to the ph transmitter. The voltage on the output side of the transmitter changes as the pH changes. I used a pH 7 and pH 10 calibration fluid to calibrate the circuit. I then used some math to determine the pH from the DS2450 voltage reading. I need to get a higer precision resistor because the cheap one I'm using is causing the readings to drift a bit. I think it's a 5%. I'm going to one that is at least 0.5%. ORP probes should work the same way with a transmitter, although I haven't tried it yet.
I've been watching this thread for some time now. I considered using the router as the base for my controller. Skill wise, I have no doubt that I would be able to do it. After much debate, I opted not to use the router for several reasons. If the hardware fails, then I have to get another router and hack it again. I don't want to keep up on all the latest methods to hack linux on these things. Also, there isn't enough horsepower to do much more than shell scripts and cron jobs. There also isn't enough space for data storage, unless I perodically dump it to another PC, but then it's no longer a standalone controller. Flexability and redundancy are too lacking for me. I decided to use a stripped install of Linux on a PC. This way if there is a PC hardware failure, it's easy to swap it out. If I don't have one I can spare, I usually have a couple Windows PC laying around. I can boot Linux (I would never use Windows) from a CD (such as Knoppix) and keep an updated copy of the application on a USB memory stick. I can switch machines in less than 15 minutes, most of the time is spent pulling the wire to the new location. I have a 75 foot length of CAT5, so location is not an issue. Hacking a router would surely be a fun project to play around with, but I wouldn't want to use it long term as a full reef controller. |
09/02/2006, 11:05 PM | #90 |
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Interesting project, but I'd probably rather just go with at least a Mini-ITX setup than hacking a router. A lot more options would be available.
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09/03/2006, 10:59 AM | #91 | |
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Quote:
I *think* the HVAC monitor will still read up to 28v ac or dc. I'm going to hook up some small voltage levels to it in the 1 - 5v range and see if it reads them ok. If not back to the drawing board I think you're right about the amp for the pH probe as being the best route. I got the op amp for free as a sample so figured I'd give it a shot. Is there a specific vendor that sells the PHMA ph transmitter or was it just a single item someone had for sale? Thanks, -Mike |
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09/03/2006, 11:32 AM | #92 |
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The 28v HVAC monitor will read the op-amp voltage, but it won't be with enough precision. With an input voltage of 28v, the resistors lower the voltage to the necessary 5 volts needed to be read by the DS2450. With an input voltage of 5 volts, the DS2450 will be reading less than one volt. So for the entire pH range, you will only have less than a volt to get your readings from.
You would either need to boost the voltage, or better yet, modify the HVAC monitor. If you want, I can send you pictures of my board with the jumpers installed. It should be too hard to de-solder the components and solder a jumper wire on the pads. |
09/03/2006, 01:50 PM | #93 | |
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Quote:
Thank you, -Mike |
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09/03/2006, 04:02 PM | #94 |
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Here is the front side:
Here is the back side: |
02/03/2007, 01:16 AM | #95 |
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IS this thread still active...? and people interested
Here is a pic of my web interface, 1wire powered by a SLUG |
02/03/2007, 02:06 AM | #96 |
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I am surely still intersted and tagging along.
Jon |
02/03/2007, 04:51 AM | #97 |
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Great. Keep us updated.
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02/03/2007, 04:59 AM | #98 |
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Feel like I'm an impostor in this "reef" forum...having a fresh water tank
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02/03/2007, 07:16 AM | #99 |
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I've been tagging on this thread for what seems like years and there hasn't been any progress. I wish someone would run with this and help explain it to people like me who aren't nearly as smart. lol
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02/03/2007, 07:16 AM | #100 | |
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Quote:
I've moved from the Linksys platform to a full blown PC running Ubuntu, so the router-based setup is temporarily out, but the spirit of the device is still alive. I haven't heard from the guy that was really driving the OWFS on WTR54G cross-compiling, so with my limited linux knowledge I decided to switch to a PC based setup. I think this will be better and give me a more robust platform with a PHP front-end and a MYSQL back-end. I've been working on it in my spare time, and have been doing some of the hardware design. My biggest accomplishment was getting pH measurement prototyped. I took vernier pH probe amplifier to amp up the pH probe output into the 0-5v range of the DS2450 quad A/D. Then it was a matter of getting the formula correct to convert from mV to pH. I found an MSDOS based program that would calculate the slope & intercept needed for calibration, but I have been unable to find a decent calculation formula (that I understand) to make my linux box fully independent - ie add in a calibration routine. Anyone have experience with pH calculation formulas? I've also been learning how to make my own PCB's with photo paper and a laser printer. I actually got my first RJ45 based temp probe board etched and soldered up last night. It's quite simple, but much better with a PCB then with my alligator clip connected workbench prototype. I've written some basic test shell/perl scripts that I can run to collect data from the sensors, but I decided to concentrate on the hardware first *then* refine the software. The software will be nothing but a group of data collection scripts, some monitoring scripts, and a web front-end. Bad Inferno - I think we emailed a while back off the OWFS developer's list. You have the discus down in Australia, correct? |
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