View Full Version : AquaMega: My electronics design project

01/19/2012, 09:23 AM
I have been attending a Community College for 3 years now and am majoring in Electronics Engineering Technology. One of the classes in the course lets a pick an electronics design project to build. The first semester was basically just choosing what to build and designing it. This semester we actually get to build what we designed.

Being I am a long time avid fish nerd I choose to build an Arduino based aquarium controller. The build I choose was inspired by reefprojects.com.

Here are the parts I choose:

Arduino Mega 2650
ENC28J60 Ethernet Shield for Arduino MEGA 2560 / 1280
I2C/IIC DS1307 Real Time Clock RTC Module for Arduino
Arduino I2C Serial 2004 LCD Module 20X4 IIC TWI LCD
Arduino Digital Temperature Sensor module DS18B20 (not water proof)
Waterproof Digital Thermal Probe or Sensor DS18B20
4*4 Matrix Keyboard Key Membrane Switch Keypad Arduino

I am planning on ordering the Chauvet sr-8 relay pack soon. I was going to go with the American Dj Power outlet strip and wore the relays myself but the Chauvet relay pack is already wired and was basically the same price when all said in done. I would just need to build a cable for it to interface with the controller...I think. :hmm6:

I am a total newb when it comes to programming so all of this is a real challenge to me. My instructor is somewhat proficient in C but the class size is quite large and isn't able to really help me out much. I am hoping someone here or on the arduino forums can aid me as I get deeper into the project.

So far I have a working digital clock as well as a semi working digital thermometer that displays the ambient air temperature.

For some reason I can't get the waterproof sensor working. I have added the needed pullup resistor but I may be doing something wrong.

I haven't started messing with any of the Ethernet stuff yet but would love to be able to get data logging working via pachube soon.

I am planning on taking some pictures of my build later on this evening so you guys can get a general idea of what I am working with here.

What I am really hoping for is for someone to possibly help me with my programming. Like I mentioned my programming knowledge is pretty limited, I am happy with what I have working so far but will really need some help with some of the more advanced functions.

I will post my code and a few pics later on tonight when I get a chance.

01/20/2012, 05:18 AM
I like your idea of using the Chauvet sr-8 relay pack. I too am working on a DIY controller and was going to use Arduino relay boards and standard outlets in my own box, but this is more of a "sleek" package and cheaper then the route I was going to go. Thanks for the info.
Looking forward to seeing your build.

01/25/2012, 08:20 PM
Ran into a little snag with the SR-8 relay box. It needs +12v to operate the relays. The Arduino will only do ~+5v. I guess that means I am going to need to build some sort of voltage doubler circuit.

I wonder if using an Op Amp would be called for in a situation like this?

01/26/2012, 06:26 AM
why not using a ULN2003?
That way you can control at least 7 of those 8 relays by using an old 12v power supply you might have somewhere in your basement.
Its easier than using 8 transistors which also should work.

Im using this IC for controlling my 12v fans


01/31/2012, 04:12 PM
You can also use the MCP23008 breakout board from project Hydra (http://www.reefcentral.com/forums/showthread.php?t=1783536). This allows you to controls the 8 relays in the Chauvet SR-8 via i2c. The 12v source is connected to this board.<O:p</O:p

03/26/2012, 08:49 PM
Update: Totally stumped on programming. Been at it for weeks and am struggling.

04/10/2012, 06:11 PM
Ran into a little snag with the SR-8 relay box. It needs +12v to operate the relays. The Arduino will only do ~+5v. I guess that means I am going to need to build some sort of voltage doubler circuit.

I wonder if using an Op Amp would be called for in a situation like this?

how do you control the sr-8? does each pin on the DB-9 connector simply correspond to each of the 8 outlets? I take it the 9th pin is the ground? Do you just apply 12v to the pin to enable the outlet? Since the sr-8 can be chained, is the 9th pin for selecting which of the two unit to control?


04/10/2012, 06:48 PM
There's 9 pins on the SR-8 one for each relay and one for the +12v.
I ended up using an unl2003 chip as an interface between the Arduino and the SR-8. I recently just got almost everything working correctly except for the Ethernet portion.

04/10/2012, 07:06 PM

Do you have a pinout?
If the 9th pin is 12v, is the ground the shield of the db9 connector?
If another sr-8 can be daisy chained, would you know how the outlets of the second one can be controlled? It would be cool if a second sr-8 unit can be daisy chained to expand to 16 outlets.

I'm going to get one, how much did you pay for yours and where did you buy it?

Are you using the Ethernet shield? I started with the UNO and Ethernet shield but found out Ethernet and SD libraries are total resource hogs and I did not have enough program space left. So now I switched to a mega.

I originally planned on using x10 to control a neptune dc-8 but found out how unreliable dc-8 is, hence looking for alternative and found your thread.

04/10/2012, 08:37 PM
after reading the manual, I realize that connecting a second relay unit will do exactly as the first one since the db9 lines are probably just straight through. so the sr-8 is an 8 channel device. I suppose with a mega, there would be another 8 lines that can be used to control the second sr-8.

did you open up the sr-8? do you have a picture of the inside? I need to know if there is enough space inside to put the arduino etc inside so the controller is just one unit. and the db9 out can be rewired to control a second sr-8.


04/11/2012, 09:37 PM
I haven't popped it open as I haven't had any reason too. I really like the idea of putting the ardiuno inside the SR-8. I'll have to look at it tomorrow to see of there's room or not.

04/30/2012, 10:29 AM
I went ahead and just bought one. the inside is full because they used larger sized relays so there is no room to add anything. But if you replace the relay board with one of those ebay 8 channel relays, then a mega + relay board would fit perfectly inside. But then, its a waste to not use the stock relay board.