..
Anyway, I've ordered the faster controller - I'm not adverse to having a spare controller as it's a long way to my usual dark sky site if something fails...
You may run into another problem: your steppers may stall due to too fast stepping.
I have 1:5 reduction before worm (belt) and I can't go faster than ~75% of STM32 capability on one mount.
Here is the ‘finished’ board. Motors are working (tested via the white molex connection, not the RJ45 points) and so is the hand controller. I just need to print a case for the STM32 controller and add RJ45 connection terminals to the motors. It’ll be a few weeks before my scope is ready to mount these and can work out the final step counts, etc. I’ll post the complete setup then.
You may run into another problem: your steppers may stall due to too fast stepping.
I have 1:5 reduction before worm (belt) and I can't go faster than ~75% of STM32 capability on one mount.
I wouldn’t be surprised if you’re correct. I’m very much a beginner at electronics, but enjoy the tinkering.
Hi Scott,
Looks like your getting it all together nice.
I'm not sure if you got my message on the onstep forum, but I'm looking for three LV8729's if you have any to sell?
I’ve received additional feedback on the onstep forum (thanks Ash) regarding the STM32 flash mod and a 10k ohm resister is recommended rather than shorting the R3 resistor. I’ve not had trouble so far, but I’ll likely make the change this weekend.
For those who are interested in the STM32 Onstep controller, or were considering it but were concerned about its speed, there is a new microcontroller to replace the STM32 bluepill, called a the Robotdyn STM32F303 and it's apparently 2x faster. It's also plug n play if you want to upgrade your existing build.
Cost of the new driver on aliexpress is about $15 delivered compared to about $6 for the blue pill and there are no issues with having to short pins or solder on additional resistors. Link is below.
I have had difficult flashing the STM32 previously. Can't remember if it was a problem with the jumper/switch to change from Run to Flash mode or something else. I've only had to do it a couple of times when adjusting settings and those events have been weeks or months apart.
I was very happy with the operation of the controller. I used it to make an EQ3 mount into a goto mount as a trial run. I've got a big old mount that I want to convert to OnStep. I'll probably use one of the more advanced/powerful controllers for that mount - it will need bigger stepper motors and drivers.
I'm really enjoying the open source software and hardware options available for astronomy - I'm currently using:
I better start accumulating bits and pieces to make the next onstep controller - need a project for the summer astronomy hiatus.
DT
Hi David
Resurrecting as well as hijacking this thread somewhat; I notice you list MyFocuserPro2 and NINA in your above post. I am currently changing over from APT to NINA as well as building the Arduino based focuser to while away the time whilst FNQ remains clouded in. NINA isn’t listed in the compatible software list for the focuser, can you confirm that they play nicely together?