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MK3 setup issues

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A bit of an update from myself.  It turns out the cheap rj45 connector I was using had bent pins that prevented connection to just the AZ motor.  That's fixed and it now operates as it should.  Haven't got much further than that at the moment.

Through my journey of this thing I have looked over the code trying to understand different aspects of it and it seems it uses ADC through pin A0 to read the pots.  I've noticed that it will jump +1 or -1 from current position when calibrating.  Odd it would fluctuate that much for you.  From what I understand it is putting voltage on the pot then measuring the analog output and converting that voltage to a number between 0-1024. I've also come to find through searching the innerwebs that any kind of static can cause it to fluctuate as well.  Seems the code is using an average to minimize the fluctuations.

Alright, I managed to make it read the azimuth sensor correctly, so it could be said that it's working now.

The issue now lies with the control using Gpredict. It recognizes it, manages it, but there are moments when it stops responding. I try to control it from the Satran webpage, and it doesn't respond either, except from "Calibration." I have to restart it for it to work again.

Is anyone else experiencing this?


I've got mine workings somewhat reliably now after going through the connections. However it seems AZ is the reverse of where it should be yet the sensor is still rising when moving CW in calibration.

Gustavo, I did experience this issue prior to having my wiring issues, though I am unsure if that was the cause. Gpredict will through errors sometimes but once it hits the threshold update it sees position again (all be it in my case opposite.)

After some fiddling around with wires for both the AZ sensor and motor I've got everything running properly in the right direction.  Gpredict seems to work fairly well for the most part, though it has froze several times and needed to be restarted. So far tonight I've tracked several SATS with it to make sure it can track the whole path.  Currently it has no antenna on it, but if it continues to work fairly well I'll get it outside.

Well, I'll comment on my progress. After delving deeper into the code, I had to enable serial port printing on several lines to see what it does at each moment.

I found that, in part, the incorrect readings from the azimuth potentiometer are the culprit.

Now, I need to investigate why it gives those jumps in readings, whether it's a potentiometer fault, electrical noise, the cable, etc. For example, it reads 402, 404, 407, 102, 415... These incorrect numbers make it behave strangely, as the code reads the potentiometer while moving to the instructed degrees. When it encounters that error, it stops. I even saw negative values (-9, for example).

Another non-negligible detail is that the elevation system has a slight "play." When set to 0 degrees with the weight of the antenna (200 grams), it can move to negative values, like -1 degree. If that happens, it triggers an error. The movement is subtle, but the potentiometer detects it. I'll see if something can be implemented in the code or if a limit switch can be added.

I'll update you on any further progress.


Hello! I would like to know if you are using the .Ino code in your projects? Mine doesn't load, and is showing an error on line 388. The .Bin compiled code works fine. Is anyone using .Ino?

Quote from joselito on 2024-01-06, 12:23

Hello! I would like to know if you are using the .Ino code in your projects? Mine doesn't load, and is showing an error on line 388. The .Bin compiled code works fine. Is anyone using .Ino?

Hello, I was able to modify the code to fix the error. Look for my email on (LU8LCT), and I'll send it to you. The forum doesn't allow me to attach files.




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