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Discussion Starter #43
Very good find on the new TFT shield, I really like he white silk screen too. Too bad you didn't get the screen with an SD card holder (like this one http://usd.dx.com/product/arduino-c...h-sensor-screen-module-901145725#.U8XqWonn8m8) to clean up a lot more of those wires.
I do have the TFT shield with the SD card, but I couldn't get the SD part working. That's why I got the little $3 stand alone SD reader. I'm assuming it was my own inexperience and lack of knowledge that was making it not work, so I am also hoping this shield makes it work for me. For exactly the reason you state. :)
 

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Discussion Starter #44
Today I started putting the project case together. I did all of the AC wiring, which included the relay board, the power outlets, a circuit breaker, a power switch, and a power cord. I'm pretty happy with how it all turned out.

Here are is the relay board wired up. 120v will go into the terminal bar, distributing power to each relay. All of the wires coming out are positioned and bent to drop right into the outlets. Each outlet pair has the little metal piece that connects the two outlets removed on the hot side, so each outlet is wired individually to a relay.



Here is the relay board dropped into place, and now connected up to the power outlets. You can also see where the power cord comes in and where the switch and breaker are (in the upper right of the pic).



Here is how it will actually stand. I plan on attaching a slightly larger platform base, but will wait until the end because it's easier to work on this way. The switch and breaker are mounted in on a small piece of flat aluminum. You can also see a long hole at the top of the box, that's where the 40 pin ribbon cable will go out to the display.

 

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Looks cool. I got my dad to play with the Arduino now too. He kill his uno usb connection. We think it's because he didn't use a diode to to protect the board from his stepper motor.
 

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Discussion Starter #49
Looks cool. I got my dad to play with the Arduino now too. He kill his uno usb connection. We think it's because he didn't use a diode to to protect the board from his stepper motor.
Yeah, live and learn with electronics. I'm 90% certain I fried my touch screen by neglecting to use resistors. As I mentioned 10 days ago, I didn't notice until I was a ways along that I had not put them on. I thought it might be fine since everything was working great.

Earlier this week the screen went pure white and now refuses to display graphics. The code is running and active, so I know the Arduino is fine. I ordered a new one for $17 from China, but now I have a two week wait. Oh well, at least they are cheap.
 

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Discussion Starter #50 (Edited)
I'm adding a new feature to my controller: CO2 Pressure Alarm

I've been thinking of a way to alert me when I run out of CO2. My 5 gallon CO2 tank lasts probably 6 months, so it's tough to keep remembering to look at the gauges. Furthermore, I use a reactor, so I can't see any bubbles.

Well today I came up with an idea. I hunted down and bought a MPX5700AP pressure sensor made by Freescale Semiconductor. I actually bought 2 for $24 shipped ($12 each) on evilbay. They look like this:



It'll sense from 0-101 PSI with a 2.5% margin of error. I'm going to hook it to the airline tubing that goes from the regulator into the reactor with a T connector. I've also already found code for how to read the values and convert them into PSI.

Once the iAqua controller turns on the CO2, if it doesn't come up to the correct PSI in the line within a minute (or however long), then I've got problems (empty tank, leak, dead power adapter on the solenoid, dead/stuck solenoid, etc). If it drops down before I cut power to it, I also have problems.

I can also kill the power to the solenoid if the PSI floats up higher than it should. I have a high quality dual stage regulator, so I shouldn't get an end of tank dump, but it'll be nice to know that I can kill if if something goes wonky. For anybody with a single stage regulator, this would be a nice piece of mind.

This seems to me to be a relatively easy way to tell if CO2 is working or not. Pretty cheap too since the sensors were only $12 each (although most of them are $20 each on evilbay).

EDIT: I was just thinking... This all assumes that when CO2 is running through a reactor under the tank there is more pressure in the air line than when CO2 is not running. I know that's the case with a diffuser, but I guess I'm less sure about a reactor. I think that's the case, but maybe I'm wrong and I just wasted $24. We'll see. :)
 

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Discussion Starter #53

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You could put the sensor between the regulator and the needle valve. That pressure should always be the setpoint of the low side of the regulator.

The pressure between the needle valve and reactor will depend on back pressure of the reactor, and may be very little.

Whiskey
 

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Discussion Starter #55
You could put the sensor between the regulator and the needle valve. That pressure should always be the setpoint of the low side of the regulator.

The pressure between the needle valve and reactor will depend on back pressure of the reactor, and may be very little.
That's kind of what I was thinking. Also not sure how check valves between the bubble counter and the reactor affect things. We will see once I get it in my hands for testing. I'll report my findings back in here. I'm really hoping I can make it work.
 

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Discussion Starter #57
It seems like with a lot of these builds, and I am definitely included in this, we keep finding more and more cool stuff to test, measure, and control, so the building never ends and the thing never actually winds up in our tank.
Ha! True enough! Well, I'm somebody who does usually finish things, but feature creep can happen. Right now I'm on hold until the replacement screen gets here, so I have time to putz. I also put a deadline on myself for completion at the end of summer, so I'm doing alright. It's also nice that I have a controller already ramping my lights and running my dosing pumps for me.

I actually bought an extra 2560 Mega, along with several other extra parts, and will probably buy an extra screen to allow me to continue development and tweaking without having to steal my controller back all the time. I want to be able to continually evolve the project, but I don't want to keep taking everything apart and interrupting what it's doing. Once it's in place, it needs to be stable.
 

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Ha! True enough! Well, I'm somebody who does usually finish things, but feature creep can happen. Right now I'm on hold until the replacement screen gets here, so I have time to putz. I also put a deadline on myself for completion at the end of summer, so I'm doing alright. It's also nice that I have a controller already ramping my lights and running my dosing pumps for me.

I actually bought an extra 2560 Mega, along with several other extra parts, and will probably buy an extra screen to allow me to continue development and tweaking without having to steal my controller back all the time. I want to be able to continually evolve the project, but I don't want to keep taking everything apart and interrupting what it's doing. Once it's in place, it needs to be stable.
That's funny because I did the same thing. I eventually had to go to a Mega on mine because the I2C bus to the screen was unreliable causing lockup issues. Now I have 2 extra Uno's and a screen that I will use to prototype a menu as soon as my summer class ends. I'm having a really tough time wrapping my head around the input side of this and it will be very good to have an extra one.

Thanks for the tip on the knockoff mega BTW! Came in handy.

Whiskey
 

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Discussion Starter #59 (Edited)
I finally got my replacement screen today. Here is the good news (it works!):



The bad news is that they mapped the touch pins where I don't like. They took the of PWM pins I had set for RGBW control. I haven't dug in too deep yet because I control my lights with IR, but if you were to use this code with PWM, you'd probably have to do some minor hardware changes to the board, or just not use this board.

The only thing that appears to stand in the way of what I need is that they mapped the LCD backlight straight to power, so I'll need to modify something to send that to PWM for the auto-brightness adjustment.

As a bonus, the SD card slot works at max speed, so that saves a bit of wiring!
 

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Discussion Starter #60
I hooked up the sensor to a little UNO and got it working today. It works perfectly, and as expected with a diffuser, but not with my reactor. With a diffuser, you can watch the PSI climb right up when the CO2 comes on, and you can watch it drop right off when you turn off the CO2.

However, there is almost no pressure required to push CO2 into a reactor, so the difference between on and off is't detectable near as I can tell. I do think putting it before the needle valve would do the trick, but I'll have to get a fitting to accomplish that. My other option would be to put a diffuser inside of my reactor, and plug the airline into it. That would pressurize the line also.

One way or the other, I'm going to make it work, because it's really slick!

 
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