Must-haves for EASY DIY controller?

Is there any schematic/drawing showing normal voltage or continuity at or between various points on the Hydra. I've got one that will not respond to turning the pH pots. I've inspected all the solder points and can't find anything that looks bad.

I don't really know what to look for. I think it would be quicker and easier to simply build a new one than to try to fix one that won't work.
 
I don't think such a drawing exists but we may be able to walk you through some troubleshooting anyways.

First, can you describe the entire environment? i.e. what is connected to the board, what firmware are you running, what are you using for a probe, what is the probe immersed in, and so on?

Also, have you done any basic troubleshooting on the board itself? If you have the ICs socketed, I would remove all of them except the main AVR. Then, put a "blink" sketch on it to ensure it is able to operate.

Then I would test the pH amp separately from the rest of the system. Take the main AVR out of the board (and any other ICs not involved in the pH amp). Put a known good probe on the pH amp. Connect a multimeter to GND and check the voltage on what would be the analog input pin on the AVR. See if you can "calibrate" it that way.
 
Actually, check basic voltages before you do any of that. Take everything off the board, disconnect from any wiring except the power supply. Check for 5v out of the main regulator and -5v out of the 7905. Also 3.3v on the 3.3v reg.
 
I started this project by downloading the gerbers for the hydra board where they were with the eagle files. I mistakenly assumed I could do the same with the relay board. I was unaware that that had changed. I was hoping to not have to bother everyone with even more questions about how to use the eagle software and how to comply with any boardmakers requirements as I must admit I have no idea what I would be doing. I thought everyone was using itead or seeed studio and that the gerbers were the same. I have received everthing I need component wise for the relay board so I will have to make the attempt to generate the gerbers as it appears no one still has them.
 
OK, I have several boards that are running the same sketch so I know that is not the problem. For testing, I'm comparing the board that does not read pH with one that will. All the ICs are removed except those for pH, AVR, and clock. Here are the readings:

V IN 7.5 from the relay board

````````````````Good````Bad

U12 right pin```````7.2````6.8
U12 left pin````````5.0````5.0
U10 upper right pin 7.2`````6.8
U10 lower right pin -6.6```-3.2
U11 right pin``````-5.0`````.8
U11 center pin.````-6.7`````.6

edit: I just realized I have the clock battery and chip in for the bad board but not for the good one.
 
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To generate gerbers:

1) Download and install EAGLE:

cadsoftusa.com

2) Download and install the EAGLE project files for the item you're interested in.

3) Determine requirements from your chosen board house. Most will actually offer you an EAGLE CAM job file. Here is the current file for iteadstudio:

http://iteadstudio.com/store/images/produce/PCB/PCB prototype/ITeadstudio_CAM.rar

Again, I stress "current" as these cheap Chinese shops have been in the habit of changing their service once or twice a year, or more.

3) Find where your install of EAGLE is keeping CAM files (do a search on your PC or look in the software for the default location). Usually, in the EAGLE folder in Program Files, there is a folder called CAM. Put the CAM file there.

4) Open the board's files in EAGLE. Bring the brd file (the board itself) to the front, i.e. make it the active window.

5) Click on the CAM icon in the top right - it looks like little blue squares of film. The CAM processor will appear.

6) Go to the file menu, choose open, and Job... then browse to your CAM file and open it.

7) Click "process job."

8) The gerber files will be written to the project's folder. Go there, get the ones you need (specified by the board house), zip them, and send them to the board house.

Ideally, before you did any of this, you'd download a DRC file (or make one) to check that your design is valid against the board house's limits. That's a similar process that I can explain if anyone wants the info.

Lessons 8, 9, and 10 from Sparkfun's intro course on embedded electronics provides a ton of really good info on EAGLE (and the hardware design/build process in general) for those interested in learning more. Here is lesson 8:

http://www.sparkfun.com/tutorials/108
 
shirley386 said:
OK, I have several boards that are running the same sketch so I know that is not the problem. For testing, I'm comparing the board that does not read pH with one that will. All the ICs are removed except those for pH, AVR, and clock. Here are the readings:

V IN 7.5 from the relay board

````````````````Good````Bad

U12 right pin```````7.2````6.8
U12 left pin````````5.0````5.0
U10 upper right pin 7.2`````6.8
U10 lower right pin -6.6```-3.2
U11 right pin``````-5.0`````.8
U11 center pin.````-6.7`````.6

edit: I just realized I have the clock battery and chip in for the bad board but not for the good one.
Click to expand...

Are you sure U11 is in the correct orientation?

It sounds to me like there is a short around U11, or some other malfunction. First I would check that it is in the correct orientation. Then I would inspect for bad solder joints, shorts around the solder joints, or shorts around the traces to/from that part (on the board itself - look for shorts under the solder mask or near pads along the entire length of each trace leading to that part).

If nothing looks obviously wrong, I would pull U11, clean the pads well, and check again - comparing the good board to the bad board, look for the same voltage on the output pin of U10. If it's OK (I'd guess it will be) you may have had a bad U11 or an unidentified short/failure near U11. Solder a new one in and hope for the best.

FWIW I've had small failure rate on these boards so it's possible there's a short on the board itself, i.e. traces touching that should not touch. This is why, especially for these larger/more complicated boards, I usually try to check for shorts to ground from signal and power traces BEFORE I put any components on.
 
Thanks DWZM - I'll pull U11 and do as you suggest. It will probably be a couple of days before I get a chance to do that and I'll probably wind up destroying it in the process but I've got another one. I was looking at the schematic and there are several caps in that area. What's the possibility of one of them being the problem?
 
I've never had a "bad" cap unless it was one I killed, but that's a good point. Several of those caps are supposed to be "backwards" with the positive pin on GND (since they're on the negative supply). So, check orientation.
 
???

???

I really feel like a total simp. in this. Dwzm again I appreciate your trying to get us through this. I printed your instructions. I went to itead and downloaded the cam file because the other user I'm communicating with tried your inst. and received an error when trying to generate the gerbers. I copied the cam file into eagles cam folder, loaded the relayboard .brd drawing and processed the cam job and got 6 files. .sts, .gpi, .stc, .plc, .sol, .cmp files. Not the .GTL, .GBL, .GTS, .GBS, .GTO, .GBO, .TXT that I expected. I had selected the rs-274x format itead said the gerber file must be in. We remain lost as this all might as well be chinese for as well as I understand it.
 
The ITeadStudio_CAM.cam file from the itead site doesn't work. I tried using it several times for my Typhon boards, and every time I tried to process the job it would give an error and force Eagle to close. After trying to send what I thought was the right files twice (they said I was missing drill and outline files), and after I explained the error with the CAM file, Sunny asked me to just send the board file and he would process it. I sent him new gerbers + the board file. They said they are going to just use the brd so I guess I still didn't get them right. Still waiting to hear if they've been processed yet.
Guess that's what I get for using chinese. That's usually what happens when I violate my "nothing china" rule.
 
I uploaded a CAM job file that works for iteadstudio and seeedstudio:

http://hydra-reef.googlecode.com/svn/trunk/hardware/studio.cam

Also, gerbers that (should) work with those two vendors for the relay board:

http://hydra-reef.googlecode.com/svn/trunk/hardware/RelayBoard/HydraRelayBoard_studiogerbers.zip

As a disclaimer, I just made them now, I haven't sent these files to any specific vendor. I generally don't keep gerbers laying around myself since as mentioned above I find it more effective to just generate them as I need them.

I hope you guys can proceed with your projects and consider this useful knowledge learned along the way rather than just a big hassle.
 
i had the same problem as loonytic on both itead and seeed when i get home i will try these new links and see if i can get them to work thanks for all the help !!!!!!!!!!!!!!!! i really want to learn how to do this stuff myself so i dont have to constantly both anyone!!!!!!!!!!!!!!!!!!
james
 
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The CAM jobs are pretty straightforward - basically, there is a tab for each output file you want. Each tab specifies a device (think: format) and a few other basic options, plus a list of which layers are to be included in that file. If you get in the CAM job and poke around a bit you should be able to get an idea of how they work.
 
i saved the cam file, installed it in the cam file folder in eagle were you said in the earlier post now i get the same error and shut down that loonytic gets i wonder if i should delete eagle and reinstall it to get it working right? i am at a brick wall with this eagle program the gerbers you posted should get discussmith and me the relay boards we need but i sure would like to get eagle to work not that i am smart enough to design the things you guys have in here!!!!!!!!!
 
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