How to correctly configure Rotator with gpredict or Satnogs using hamlib? MATLAB related

SatNOGS Software
1

Hi, my name is Julian I am from Colombia, I am a newbie and this is my first post.

I want to capturate Azimuth and Elevation in realtime using Matlab and serial Communication

I had installed Gpredict 2.3.37 on Windows 10
Also Hamlib w32 3.3
And also uploaded “satnogs-rotator-firmware-master” to an arduino UNO from
https://community.libre.space/u/quartapound

I created a Module in gpredict with my location and a generic antenna to communicate with hamlib on localhost and all default options

Then, with the Arduino UNO plugged in, I started hamlib with the following line on CMD:

“C:\Program Files (x86)\hamlib-w32-3.3\bin\rotctld” rotctld -m 204 -r COM10 -s 9600 -T 127.0.0.1 -t 4533 -C timeout=500 -C retry=0 -vvvvvvvv > pause

Everything looks fine untill now but then when I hit “Engage” on gpredict the CMD console shows this ERROR:

read_string(): Timed out 1.49158 seconds after 0 chars
easycomm_transaction read_string failed with status -5
easycomm_rot_get_position got error: -5

No, don’t have any electronics mounted besides the Arduino UNO with no Shield nor any PCB, just a Serial to USB converter used for MATLAB communication

The other day I did the same and it worked, here is a video:

youtu.be/rPlLijxaUcs

Any ideas on why is it not working now?

I also created a Station on SatNOGS network and used “image_2020-03-04-Raspbian-SatNOGS-lite” or “artifacts.zip” on a Raspberry Pi 4 and configured the basic setup, the /dev/ttyACM0, and connected the arduino but I didn’t get any data on the serial port apart from “ID;” or “FA;”

I feel this is a configuration related problem but I’m no expert, I hope you can help me

Thank you for the long reading and any help will be very much appreciated.

2

Hi Julian welcome to the community. It’s an interesting and frustrating hobby. I too have been trying to build an antenna rotator as you can see from my blog (http://www.cyclebikeapp.com/satnogs)

I have seen your ERROR before. Rotctld must get a position reply from the easycomm Arduino code or it disconnects. Usually this comes from a position encoder on the rotator, but you say you don’t have any hardware connected. For debugging, I have just used a command to send a reply when easycomm receives a position command. Something like Serial.print(“AZ123 EL45”); Notice the space between 3 and E.

(I believe you have been using the code on gitlab here (https://gitlab.com/Quartapound/satnogs-rotator-firmware), not the link you posted.)
Tom

1 Like
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Hi Tom, thank you for replying

(I believe you have been using the code on gitlab here (https://gitlab.com/Quartapound/satnogs-rotator-firmware), not the link you posted.)

Yes, that is the code I am using, sorry about the posting, I am learning how to do it just now

For debugging, I have just used a command to send a reply when easycomm receives a position command. Something like Serial.print(“AZ123 EL45”); Notice the space between 3 and E.

I will try this and let you know how it goes.
Thanks.