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You are going to need some kind of microcontroller, or computer with RS232 to interface the card reader. The idea is, you scan your card - the controller reads the serial signal and decides if your card is correct or not - if card passes then you release the mag lock on the door. You prolly need...

Not bad at all poppa, looking good. Just missing a few high speed filtercaps(some .1uF close to the IC) but other than that it looks like it’ll workfine, and easy to build to boot! On your next revision make sure you make a groundplane poor (use the polygon tool, and type GND in the naming bar...

My aero chamber uses 6mil and its 3 foot deep, granted I am not flooding it but when I rinse it it regularly holds more then 2 inches of water un supported. For your requirements a table made from 2x4's and a plywood bottom would give you ~2inchs of flood depth and whatever size you want, cut...

hehe, Poly is who I get some of my COTS cases from hammer turned me onto them a while back. They have some cool stuff that works pretty well vanilla. But theyre custom prices can be expensive, better to find a local shop to machine them for you. I posted a pic with a controller in a poly case :)...

Just get some 6mil or greater poly and line your wood box with that. If you keep the poly in one piece it cant leak except where you put holes for your bulkhead fittings.

I like how your going to design cases, that is one of my major hiccups and just chose to COTS most of them. As for topology while my beta testers are star with dumb units(relays, sensors), I decided to shift most of the units into "smart" units. This way you could operate in a distributed mode...

I just upgraded my pH sensor interface with a microcontroller added to it for pretty much this reason, the sensor itself is baiscally a stripped down arduino now but still quite reasonable at only 21 bucks. I broke out serial Tx/Rx, I2c and a couple other pins. I also have a USBtoXbee/rs232...

Dont waste your breath on Wee, sonar I already explained what you have in the quote above several months ago, and IIRC you did too :) obviously he doesnt pay any attention to facts when they are presented. Everytime someone makes a post similar to this, him or his side kick stepaniesloan come...

If 400aZip is in fact wired with 14awg wire he could infact go to a 20 amp breaker, this will of course remove most of your 20% safety margin from the circuit but you should still have enough in the wire to be safe. I suspect the extension cord is causing an increased amp draw due to a voltage...

For some reason I feel the same hehe. /me Watches snow storm creep over mountains... getting closer hahaha.

Your quite welcome poppa, I am just happy to see others taking interest in this endeavor as the more that participate the better our results will be especially if we share our failures and successes with others. I am starting toget better at documenting as I go, but I needed to restart some of...

Sounds like you got a great start, and I like the idea you have of chaining the modules together. I think this is the way to go and allows the most flexibilty with out any major downsides except maybe some communication overhead between units. with some careful design you can squeeze these into...

A point to consider is that pH probes age and should be replaced periodically, this is just something to think about when buying pH meters. Some pens dont allow the probe portion to be changed some do, I have changed my milwaukee's a couple times over the years for example. you can tell when the...

The pumps magnetic field is most likely causing some noise on the pH sensor end, when AC fields and/or DC galvanitc action(e.g another pH probe) is present in the source it is best to take a sample in a clean non reactive container. You can also account for this noise and adjust for it, but as...

The temp and humidity sensors are really really easy(especially if you do a 1wire or I2C digital temp sensors) the lm335a is a decent and cheap analog temp sensor, put it into a stainless or titanium tube(or even heat shrink tube) and seal it with expoy and you have a pretty damn good temp...

I dont have webcams, but I can vpn in and check/control my ph,ppms,co2, water levels, temps, relay status amoung other things. though a webcam would be really cool and a great way to just get a quick look. pair one with a pantilt and you could move it around to see the whole area.

If you are familar with the Arduino prototyping platform, and are a bit handy with DIY stuff in general you can build a simple system to coordinate these too for very a reasonable price. For example Arduino Uno - 30 bucks couple solid state relay breaout boards, or mechanical relay boards...

I am right there with you buddy I have a couple setups running now as testers. You will find it works really really well. Over the last year or so I have refined some of the code and have created a few designs to help replace some of these crap timers and stuff out there. My main test setup is...

It sure doesnt help that I've been dragging my ass getting your setup to you:) I just about have its(below) brother finished and we'll have 2 exact copies for any troubleshooting needs. It needs a bit more firmware tweaking, but its beta cousin seems to be doing fine(spare the fact I had to add...

If you have a computer with an lpt port you can build a timer with an AVR µC (for real small try an ATTiny85) its not much more complicated then the 555 and you can program it too! you can use your lpt to program it, all it takes IIRC was like 3 100ohm resistors to make a programmer.