Quartapounds SatNOGS Rotator v3.1


Thank you very much for your explanations, did you put jumpers to the drivers, if so how many micro steppes?


I didn’t have the proper jumpers because they didn’t come with the board!(tsk, tsk)… so I just put a blob of solder to connect all 6 pins on the back of the board (to enable the highest level of microstepping)


3D printing a case out of PETG right now! it’s going to be a long print… easier than building a case by hand though.

I’ll upload the STL once I know it works. I plan on cutting the hole for the bottom axis by hand… I was more worried about getting the dimensions right, I didn’t want to make the hole in the wrong spot.

The bottom will be 195mm tall, and the top cap will be similar dimensions, probably a bit shorter, (except with cutouts for the elevation axis) and will overlap the lower box to make things waterproof.


This is what I’m thinking for the top… the bottom seems to be coming along well


It’s getting there! Going to bed now will wake up to completed box or a disaster in the morning haha


Hello, a little news of the progress of the rotator, I finished the mechanical parts for two rotators, one for me and one for friend he does not have the printer 3 d, I wait for the profiles of at motedis with impatience to finish the project, see you soon.

Couple of Newbie Questions

Hey @remy!! This is nice!! Feel free to make a new topic in gallery for your build. Also i have one question , why are you building the v3.0.1 and not the v3.1?


@quartapound, how do you achieve the EMI shielding of rotator? The motors are producing noise. For example in v3.1 reference build we use sheet metal box.


Hello @Azisi, I build simple with motor nema 17 + Uno + Shield cnc. v3.1(mixt).


I am hoping a layer of aluminum tape on the inside of the case will achieve this. I may use copper tape instead.


I’m struggling to get the code to compile. A couple of dumb questions.

Did you use the arduino ide to compile and upload?


Did you follow the steps in the readme? I am not sure I understand them so am probably making an error somewhere




Hey! @remy which t-slot profiles did you order (lengths)? You may have a problem with the thickness of axis side part of picture. Because t-slot profiles with length 140mm fit only to v3.1.


yes I used the arduino IDE (1.8.8). …what errors are you getting? I followed the steps in the readme which directed me to getting the accelstepper library,



At 1:12, the SMB operator missed a key opportunity for infinate 1-ups.


I’ve had a few but worked through most of them. I suspect they will be as a result of the IDE rather than anything else. (Also having some issues logging into community as well)

So far I have used same version ide that is in the readme. All libraries are in. Added the SatNOGS board. If I compile / verify with SatNOGS board I get error referring to watchdog.h

In function ‘void_vector_6():
error: expecting primary-expression before’. ’ token while (rs485. available () >0)

The watchdog line it is struggling with is

incommingByte = rs485.read();

Get same error when trying with Uno board (which it is). Board OK as have uploaded other sketches to it to check.

Any hints?


Very good Job!
I also study a counterweight to mount on my parabolic grid antenna



YES! I had trouble with those lines too. I had to comment out all of the watchdog lines as well. I think it’s checking for communication between the Pi and Arduino.

just do a search for ‘wdt’ and add // before all the wdt lines and comment them out.


How I start the Rotator software on my PC:

Install Hamlib: https://sourceforge.net/projects/hamlib/

Figure out which COM port your Arduino is (Mine is COM7)

create a .bat file in the same folder as rotctld (I found it in C:\Program Files (x86)\hamlib-w64-3.2\bin )
with the following (modify for your com port)

rotctld -m 202 -r COM7 -s 9600 -T -t 4533 -C timeout=500 -C retry=0 -vvvvvvvv

Download Gpredict https://sourceforge.net/projects/gpredict/

Edit…Preferences…Interfaces…Rotators…Add New
Name host port
Arduino localhost 4533

Start your .bat, in the top right corner of Gpredict, click down arrow, then ‘Antenna Control’

…Clicking ‘Engage’ should get the Rotator to start working.

Once you have configured some satellites you can them select them and click ‘Track’


Getting there…Arduino code uploaded connection made but iffy getting errors now in that batch file output and no movement

serial_flush called
write_block called
write_block():491 failed -1 - Input/output error
easycomm_rot_get_position got error: -6
rotctl(d): P '343.28' '3.01' '' ''
rot_set_position called
easycomm_rot_set_position called: 343.279999 3.010000
easycomm_transaction called: AZ343.3 EL3.0 UP000 XXX DN000 XXX

Assuming this is some kind of positional error