DAQ questions

So I'm right that these DAQs can read slowly as well as fast? Or read in blank data or the same data and ignore it until it gets new data? I am getting confused. I now have the money to buy something, but have to sort through the info. I will get it eventually. Thanks for being patient with me.

So is the real complication between DAQs and 1-wire systems the code and type of info it sends? Or am I still messed up?
 
I was leaning towards getting the DAQ starter kit, but if it doesn't work with 1-wire probes, the DS18S20, and the DS1621 then I have to go back to finding full size temperatures probes at a cheap price.

I'm starting to think I might just order both
A. HVAC Monitor and the USB interface with DS1621 and a ph probe. (as well as DS18S20, so I am covered for whatever I need.)
and
B. DI-148U Starter Kit Low-Cost USB Data Acquisition System

But that will put me at close to $100

So option C I think is eliminated from the equation at this point. Can some one help me and say, “you do not need option for any of the probes you would use with an aquarium”.

Would the same probe work with both the DAQ and this HVAC? Or would they be different parts? If the probes would work with either device then I might as well buy one of those if I find a good deal. Let me know if you see any.(I’d prefer brand new over used on ebay.)
 
A DAQ basically consists of an A/D converter. The A/D converter takes an analog voltage and turns it into a number. It does this by comparing the input voltage to a reference voltage.

An 8 BIT number has a maximum value of 11111111 which equals decimal 255.

So lets say your voltage reference is 5V. That is 256/5 = a resolution of .01953125 volts per step.

That means for every .01953125 volts that the input increases above 0 Volts, the number output by the A/D will increase by 1.

Lets say the A/D reads 127... That would mean that there was 2.48046875 volts on the input of the A/D.

Now if you had a 10 BIT A/D that would mean that you have a max value of 1111111111 (1023 decimal). Your same 5V reference would equates to 0-1023 steps (1204 acutal values) so the resolution is 5V/1024 = .0048828125V per step. An output on the A/D of 127 would mean that there was .06201171875 volts present on the A/D input.

Pheew....

Now the "DAQ" is a fancy box that provides input and output capabilites to connect the A/D to a computer and to the device to be sampled. The "DAQ" may have settings for sample rate, reference voltages, software interface variables etc. It gives you a way to do something with the NUMBERS that are returned from the A/D circuits.

The Dallas 1-wire stuff is TOTALY different. The 1-wire devices are small integrated circuits that perform various "smart" tasks. A typical 1wire sensor will return a 16 BIT BINARY WORD (or several depending on the command sent to it.) These binary "strings" of data include:
The unique device ID (each device has its own unique serial number). The Device "family" and "model", the "data" requested in the form of a 16 bit binary "word". A CRC checksum etc.

The sofware then must act upon these returned values and format them for display or processing in some other fashion. The 1-wire devices can be interfaced to the computer with a 1wire adaptor and a "driver". There are plenty of VB, VBSCRIPT, JAVA, C++ etc examples for reading and writing to 1wire devices.

Sampling RATE:
This is a tricky subject. Lets say the DAQ is sampling at 1000 times a second. As long as your input doesnt vary over that time, then it does not matter when you "look" at the sample. Howver lets say that instead you have a 60HZ signal hooked to a rectifier adn then to the A/D. The rectifer output will have a lot of ripple in it instead of being an exact DC voltage. Now you must look at the sampling speed and the ripple speed and determine a way to take samples at ether the PEEK of the ripple, or by averaging a certain number of samples that may fall anywhere in the voltage ripple. I know that sounds confusing....

Look at it this way. You will have a probe hooked up that will be outputing a voltage. The values should change rather slowely... over a few tenths of a second to a few seconds for even a small change. It does not really matter how "slow" your A/D is. You only want a snapshot of the volage every few seconds or minutes.
 
Thanks a lot bean, that makes sense to me for the most part, I'll have to re-read again later for it to really sink in. I greatly appreciate it, I want to understand these things because I feel that it will become very useful where ever I end up.(right now looking at grad schools and aquaculture facilities near the Solomon islands.

Do most people order their 1-wire devices right from http://www.maxim-ic.com ?? I tried to sign up with their site last week and my confirmation e-mail never came through.

Now wondering how many probes I could use, the first home made project allowed you to do many probes.(like hundreds) With a cat 5 through USB how many would I be limited to? I forget the number of wires running through each type of cable.

Off topic, but Bean did you hear about MACNA coming to your city next year? I don't know if it is just a rumor because I could not find any more info on it, but I heard something about it on reefcast. MACNA ON THE WEST COAST! I think I may start up a savings account just to set aside some money so I can afford to go and maybe even buy something, lol.

Jon
 
Just wanted to thank everyone again. I have come a ways in understanding this stuff through my Digital Design class and we have gotten into some topics that directly apply to this stuff.

Actually I think it was a couple of days after BeanAnimal's explanation of sampling rates and the one wire stuff that we moved from combinational logic to sequential logic. At the same time I was just starting to play around with my "black box" and started to figure things out. (bread board+power)

<IMG SRC="http://reefcentral.com/gallery/data/500/48214HPIM6406nastythumb.JPG">

Between Intro to Digital Design, Organic Chemistry, General Ecology, Entomology Lab, work, and the new gf I haven’t been able to look at any reef stuff for a while. I am very interested and it is dragging me in, I just need to figure out where to buy a ton of parts from to get me started.

I ran buy radio shack today, not to buy anything just to look, and saw some things I wanted to pick up, but I know there has to be cheaper ways and could possibly be better products out there. I am not sure if this link will last, but on this page I was looking at the universal solderless breadboard, the modular IC breadboard socket, and the jumper wire kit. HERE: http://www.radioshack.com/family/index.jsp?cp=2032058.2032230&categoryId=2032265&pg=1 I wanted to ask what you guys thought of the extractors as well.

I would like to find a site where I can order most of my part if possible. I would also like to order are all the parts for these projects so that I can start messing around things:
http://www.anotherurl.com/therm/schematic.htm
http://www.riccibitti.com/pc_therm.htm
I suppose I should just order a couple of different model temp probes and then just try them out and experiment when I get them. And I should get a 1-wire USB interface.

Where would you guys buy all these parts from? Any recommendations on some solderless breadboards I could play with?


Jonathon
 
Where ever I order from I will probably get one or two 12 Volt DPDT Relays. I am going to set up an <A HREF="http://www.aquahub.com/store/autotopoffcomp.html">auto top off system</A> when I get my sump hooked up. (hopefully by this Jan at the latest) I will be using switches from more then one company as sort of an extra back up, as well as a chance to see what I like. In the future I would like to tie the status of these switches to the PC so I can see if the switch is on or not. (Show status on my website and perhaps have the PC cut off the pump if the switch has been on too long.)

Jonathon
 
Just get a few 3M or similar breadboards from eBay. I have 6-7 large (12x12) and still find myself wishing I had more. Invest in a dual bench supply (eBay is again a good choice). You can buy jumper wire kits... they say time, but then again I am too cheap.

Buy a cheap used Fluke or Simpson digital bench meter AND get a Simpson 260 (any series) analog meter.

http://cgi.ebay.com/Fluke-8600A-Digital-Mulitmeter-Meter-Bench-Top_W0QQitemZ140015387036QQihZ004QQcategoryZ58275QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

http://cgi.ebay.com/Fluke-8050A-Digital-Multimeter-DMM-Multi-Meter-Bench_W0QQitemZ270005241846QQihZ017QQcategoryZ58275QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

http://cgi.ebay.com/2-SIMPSON-METERS-260-SERIES-4-6XL-MANUAL_W0QQitemZ260053148378QQihZ016QQcategoryZ58276QQrdZ1QQcmdZViewItem

http://cgi.ebay.com/Hi-tech-Digital-Bench-top-Adjustable-Power-Supply_W0QQitemZ330051392339QQihZ014QQcategoryZ3240QQrdZ1QQcmdZViewItem
http://cgi.ebay.com/Digital-Read-Out-3Amp-Bench-Power-Supply-3003X_W0QQitemZ320048951337QQihZ011QQcategoryZ1504QQrdZ1QQcmdZViewItem

Then you can look for a CHEAP $100 or less used tektronix scope, as it will soon come in handy.
 
BeanAnimal I saw the drawing you did (forsanjay). Did you use software to make that? We use something called "Multisim 8" here at school and it is full of bugs and won't even work on my computer.
Oh and I had meant to ask about multimeters good thinking. My budget is a bit limited now though.
To get started what do you think of this?: http://cgi.ebay.com/NEW-Simpson-1-8...ryZ58278QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


Where would you buy the resistors, regulators, DS18B20s, push buttons, transistors, capacitors, and so on for the projects? I would like to find some place I could get most of the parts shipped together.
 
Dun remember what drawing that was... do don't know what I used to make it. Could have been protel, eagle pcb, or visio.
Yes multisim has a lot of bugs... but so does the $20,000 full blown Protel package!

Your best bet for small circuit CAD is the free version of eagle. It is buggy and has a very anoying anti-piracy feature (don't try to crack it or you will end up with randomly scrambled drawings). Even if you pay the money for the basic version, the stupid copy protection ruins drawings on occasion!. Still it is the best freeware/pay for full version you will be able to afford.

That is a panel meter.... not a multimeter. You want an OLDSCHOOL digital bench meter like the ones I pointed out. You can grab one for $25-50 usually on eBay.

The analog meter is a very important tool. Digital meters suck for checking transistors, caps and other devices that charge/discharge. Every bench should have an analog multimeter!! If you can only afford a single meter right now... get the simpson analog. They are built like battleships and they are one of the best analog meters made. I have a new 7 or 8 series that I paid $200 for ($700 or more retail). If you get a 3,4,5 series for $50 you still got one hell of a bargain.

Overstock and such:
apexjr.com (a friend of mine... great stuff!!!)
Allelectronics.com
surplus sales of nebraska
eBay

Retail:
Allied
Digikey
Mouser
Newark

Best place to search for pricing on a retail part:
http://www.findchips.com/

Speaking of eBay, that is where you want to by discrete components. Always search there before you buy parts anywhere else. I would just go ahead and order a few hundred pieces of each of the basics building blocks... like:

Transistors (both NPN and PNP) get a small signal series and then some larger drivers:
2n3906
2n3907
TIP series driver transistors
maybe 2n222 also (similar to the 2n39 series)

Grab a package or two of 1/4 carbon resistors on an assortment
Grab a package or two of 1/4 metal film resistor assortments
Grab an assortment of small ceramic and electro caps.
Grab a pile of diodes both small signal and zeners (1n4008 or similar).
Grab some 8, 10, 12, 14, 16 pin IC sockets if you feel inclinded
Grab a few cheap opamps and maybe a few 555 timers.

Most of that stuff should be priced a few bucks per 100 :)

You can spend about $50 and get a decent small parts bin with the basic everyday building blocks including some toggles and momentary switches. You will spend that at ratshack on a handfull of parts.
 
Ok this was to be a major part of what I wanted to get done last month during the month I set aside to work on my reef stuff, but I ran into a brick wall when my newest and largest tank leaked, and my budget ran out. I am going to order some parts tonight regardless of the fact that it will bring my credit card close to its max. I have sat on my ideas and plans too long and want to make something happen.

I will be ordering the 1-Wire USB Adaptor from hobby boards and some 1 wire thermometers(if I can figure out how to order them), just to get me started with something.

I need to learn how I can take part of a .xls or a .txt file and embed it into part of an .html or some other webpage for viewing on my website. I have kept some records of my tank parameters in a .xls that I could perhaps practice with.

I was lucky enough to get a handheld for Christmas and plan on getting some old web cams hooked up very soon so I can keep an eye on things from anywhere.
 
Even though it seems like you have made your decision and this won't matter, I'll be briefly answer a question you had posted earlier.

As for National Instruments (ni.com) you were correct in not choosing them. I use their equipment extensively at work and it is great, however it is quite expensive and, for your use, much like killing a mosquito with a cannon.

Anyway, good luck and happy coding.
 
Are any of you really good with Network security? I am trying to set up my network using my new linksys router and I'm having trouble getting something set up I've done a million times in the past, but it's been a while. What I was planning on doing is adding basic zone alarm to all of my PCs, disabling windows firewalls on all of them and giving everything static IPs. Then I could configure the firewalls on the computers so that nothing could get access to the PC monitoring my fish tanks accept for the computers who's IP address I have assigned. When I try to give the computers static IPs though I lose my access to the web.

Jon
 
Not the best plan...

but anyway.

Lets say the LINKSYS is set to provide DHCP addresses starting at 192.168.1.100 Lets also assume that the LINKSYS has an IP address of 192.168.1.1

Lets say you have 5 computers:
Set their IPs as follows

IP: 192.168.1.5 for the others it would be (.6, .7, .8, .9)
Subnet Mask 255.255.255.0
Default Gateway 192.168.1.1
DNS 192.168.1.1

You can leave the windows firewall intack and only forward the needed ports to each IP.

What do you plan on using for remote access and from where? Zone Alarm is a PITA.
 
Well what I plan to use it for and what I end up using for are often two different things, lol. Over everything else I would like to be able to view my webcams on my reef tank using my handheld and laptop. If I can open up some of the webcams at certain points to my website safely I may do that as well.

I would soon like to be able to control my X10 devices as well, but I won't do that until I am sure it's safe. It would be nice to be able to turn a pump off if I'm watching my cams from the other side of the state and see it shooting water onto my media center gaming PC.

Jon
 
I got off topic. I had tried to do exactly as you had described, but it had not been working. Can you suggest a cheap or free alternative firewall that lets me mess with ports and ip permissions? Or perhaps a completely different method of sharing info and files between my 2 desktops, my laptop, and my pocket pc?

Things are going to change a little bit for me in the near future as I am ordering a new gigabit router with a storage link for a USB drive.
 
I looked into doing a VPN, but was told by one of my classmates that it wasn't worth the money at this point.

Jon
 
You must log in or register to reply here.

Similar threads

F
Type K thermocouple on Apex?
Replies
7
Views
237
FishTri
F
R
DIY AI-coded ESP32 based aquarium controller
Replies
0
Views
472
ronnyking
R
S
Sump at Same Level as DT
Replies
9
Views
221
wvned
wvned
S
Top cross frame broken on 50 gallon glass bow front tank
Replies
2
Views
426
SantaMonica
S
xclusive252
Kessil help please
Replies
4
Views
214
wvned
wvned
Back
Top