Analog Gauges, Ethernet Wire

[trehugr]

Getting ready to make some improvements in piping and and temp monitoring. Questions are as follows:

1. Do analog temp gauges need to be used with a well, or can their probes go directly into the water ? (as I currently have them)

2. I plan on using a few of these ... (broken link removed) I ran a Cat5e cable to the boiler room thinking I was going to use a camera to monitor the EKO. Could I use this wire instead for these digistat's ? These temp monitors will all wind up being parked here at my computer area. Is the wire heavy enough to handle the 24v current and or battery current ?

 

[2.beans]

with most sensors youll loose accuracy with to small of wire. that is if your extending the probe wire. they use 20awg so i think youd have to use that or bigger.

 

[WoodNotOil]

I agree that the signal will degrade too much over a long distance on thin wire. I had this difficulty with my homemade control losing signal over 50ft. Most speaker wire should be around 18 guage and that is typically okay for extending these probes. Could get expensive though if you are going a long distance with them as each probe needs a pair of wires...

 

[Nofossil]

Generally, the problem with long wires is the capacitance, not the resistance. The Digi-stat uses thermistors which are pretty immune to wire length. Ethernet cable can easily handle the voltage and the current. I use it even to connect the my zone valves and thermostats (in addition to all of the temp sensors).

 

[Gooserider]

Remember also that in a CAT5 cable you have 4 pairs - I've heard of folks doubling up - instead of just using one pair for a signal, use one pair for each side by stripping and twisting the ends together. You get fewer signals per cable, but stay with a relatively low budget wire setup.

Another option is to get one of the little single board units like a "Gumstix" or a "Beagleboard" that has an ethernet connection and put that in your boiler area as a data collector, sending the info back as a digital datastream...

Gooserider

 

[trehugr]

How complicated would that be Gooserider? If it was something a novice could do then I may attempt it. I just dont have time to learn a whole new "hobby" . Tell me more.

 

[Gooserider]

How complicated would that be Gooserider? If it was something a novice could do then I may attempt it. I just dont have time to learn a whole new "hobby" . Tell me more.

NoFo would probably be able to give better details, but it could be somewhat hairy to get setup. I know how to do the hardware end, but I'm not sure just what is available for software. (Probably a fair bit since it would be largely Free/Open Source stuff) Hardware wise, you would need a small "single board" computer, with data collection inputs appropriate to your sensors, or an interface board that does conversion. I know they exist, but I'm not sure just what the options are as it's a market I haven't delved into very deeply. You could use a regular X86 PC, but that is a bit overkill and will need more power than one of these dedicated boards.

An X86 box is usually going to need on the order of 1-200 watts, and have a hard drive, and other extra equipment, plus it's a big box. The single board units are tiny ("cigarrete pack" size or less) typically use a flash drive for storage, and draw only a couple watts of power.

Then it's a simple enough matter to wire the sensors to the inputs and plug the thing into an ethernet jack (or some will do wireless)

The tricky part, where I'm not sure of the details is to do the programming - you would need to program the SBC to collect the info from the sensors and pass it to the ethernet line in a format the machine on the other end can deal with - either on a "push" basis or when "polled" - and set up your machine to display or do whatever else you'd want with the data. I'm not a programmer, so that side I am not at all sure about how to handle.

Gooserider

 

[Nofossil]

What you (and nearly everyone else) really need is the soon-to-be-legendary NoFossil Control System:

http://www.nofossil.org/nfcs/

Sorry for the blatant marketing-speak, but the site is for the benefit of potential investors.

I hope to have actual prices soon for people who want one. I've also made the details available at no cost for folks who want to roll their own. As Goose says, these single-board systems are really nice but not for the faint of heart.

 

[trehugr]

Well NoFo, you have been a busy boy, between cutting, splitting and starting fires... how do you do it ?

The very first thing I look for when Im researching 'puter stuff' is it Mac compatible ?

NoFo, if you tell me I need a PC, complete with worms and virus's to run your machine, then I will have to come to Vermont and make you drink a Bud Lite while I sip on a nice Dogfish Head Worldwide Stout.

trehugr

 

[Gooserider]

Agreed, your setup is essentially what I had in mind, though perhaps more fancy in terms of available functions than what the OP was asking for...

Just out of curiosity, how close do the descriptions on the other parts of the website match what you are describing on the investor page? - I'm assuming that most of what you are describing is COTS hardware, is the software on your website also part of the setup as described?

(I will also express mild amusment at the description of a system with "only" 32mb each of flash and RAM as "limited" - true that is by modern standards, but I remember back when a fully loaded PC had 640K of RAM (Which Bill Gates thought would be more than anyone could possibly need...) and TWO 360K full height 5.25" floppies...)

Gooserider

 

[Nofossil]

NoFo, if you tell me I need a PC, complete with worms and virus's to run your machine, then I will have to come to Vermont and make you drink a Bud Lite while I sip on a nice Dogfish Head Worldwide Stout.

trehugr

That would be an appropriate penalty, and one that would cause me considerable suffering. Fortunately, no Windows software was used in the development of the system, and none is required to use it. Once it's configured, it just runs all by itself, though you can check in any time from anywhere via browser.

My development system is a Linux desktop machine, and the NFCS only requires a web browser (on any platform) for operation. For anyone who wants to develop their own applications, I would recommend a Linux development system similar to my own.

To Goose's question, the investor description is for the same system, just sidestepping the public domain nature of the design and software. There are people who have downloaded the software from my site and are now running it on systems that they've built from my BOM. If you're comfortable soldering and cross-compiling in a Linux environment, you can do it yourself - just contact me.

My interest in having them built is that there are lots of people who could use them and can't readily build their own. I believe there's a real market for off-the-shelf versions of the NFCS, hence the investor pages.

It's still massive overkill if all you need to do is control a pump or a valve, or monitor a temperature or two.