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ph subsystem: Failed read probe - Printable Version

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ph subsystem: Failed read probe - Mightythias - 04-20-2021

I received my Robo-Tank yesterday and it is awesome. I got everything configured and working great.
But sadly today at about 2pm things just stopped working. The PH probe went from reading 8.16 to reading 2.6 then to -1.3 and is now showing an error saying it cant read the probe anymore.
I deleted the pH stuff and readded it and now I get an error when trying to calibrate. 
{"error":Failed to execute.
Error:\u0000\u0000\u0000....
| HTTP 404

And there is an error in the log stating:
ph subsystem: Failed read probe:pH SumpError:Failed to execute. Error:

I was also controlling my lights via 0-10v analog which was working great and also all of the sudden stopped working.

Any ideas whats going on?


RE: ph subsystem: Failed read probe - Rob F - 04-20-2021

Hi Mightythias, sorry for the trouble, both of those run on the I2C bus so it sounds related. If you type in the following command in the Raspberry Pi terminal do you get a list of addresses, you should get 40, 70 and 63.

i2cdetect -y 1


RE: ph subsystem: Failed read probe - Mightythias - 04-20-2021

Before when I ran this I was getting the 40, 70, and 63. Then after a reboot I was getting a ton of values on like every line. Now when I run it I get this:
pi@:~ $ sudo i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --


RE: ph subsystem: Failed read probe - Rob F - 04-20-2021

Thanks, something definitely wrong with the I2C bus, the pca9685 runs the 0-10v and DC ports that's why those aren't working either.

I think there's two possibilities, a 3.3v to 5v converter for the I2C bus or the Pi. Any chance you have a volt meter and able to read a couple points on the board if I mark them in a picture?


RE: ph subsystem: Failed read probe - Mightythias - 04-20-2021

Unfortunately all I have is a voltage tester. I don’t own a voltage meter. Is there anything else I can do?

I also have a raspberry pi zero W that I can try to configure for the robo-tank and see if that makes a difference?


RE: ph subsystem: Failed read probe - Rob F - 04-20-2021

No problem, yeah if you could try the other Pi that would be great.


RE: ph subsystem: Failed read probe - Mightythias - 04-20-2021

Will do and report back. Thanks.

Ok so I swapped out my pi 3 for the pi zero W and am getting the same errors for pH.

ph subsystem: Failed read probe:pH SumpError:Failed to execute. Error:

But right now I am getting the i2cdetect issue that I saw before it was blank

pi@raspberrypi:~ $ i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
10: 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
20: 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
30: 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f
40: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
50: 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f
60: 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
70: 70 71 72 73 74 75 76 77

Just to clarify the lights 0-10v and the ph probe didn’t work with either of the pi’s


RE: ph subsystem: Failed read probe - Rob F - 04-20-2021

Thanks for trying, looks like a 4 cent part is bad. :( I'll get another board shipped out tomorrow, sorry for the troubles.


RE: ph subsystem: Failed read probe - Mightythias - 04-20-2021

Wow that’s terrible I know it’s not your fault at all. I really appreciate everything you do! Thanks so much you are awesome. I look forward to receiving the new one. I am so impressed with how easy it was to setup and configure. I will be sure to spread the word and tell everyone how awesome a product this is and how great your support is. I know several tank owners that would love this product.

You have the address to ship to? If you could just shoot me an email with tracking.
Thanks again


RE: ph subsystem: Failed read probe - Rob F - 04-20-2021

Thanks for the kind words and understanding.

Yeah it stinks, that part is typically solid but obliviously not this one. I do have your address and will be sure to send the tracking number when I have it.