Which controller to use for next OnStep build?


 

Hello everyone.

My first and only OnStep build was with an MKS Gen-L v2.0 board and TMC2209 drivers.  Everything works very well, other than my slew speed is limited to 1.1 deg/s at 32 microsteps (with these Non-SPI drivers the microstep value must be fixed). 

When I first built the board, I wanted to do near zero soldering.  Now I am much more comfortable with soldering and de-soldering, and have no reservations with assembling components.

I would like to build a faster board BUT, likely keep the TMC2209 drivers since I have extras.  I see that the TMC5160's are now a fortune (and unavailable), and the TMC2130's not as good for heat and higher amperage rating.

From everything I have read, and the many, many posts I have seen of the various boards, here are my brief thoughts:

Fystec - Great all-around, but seems to be vulnerable to screw-ups and finicky about flashing the software.
Wemos R32 / CNC V3 - Seems like Ken Hunter or George Cushing has these as a package which is very convenient.  But I have seen many posts with difficulties and unpredictability with these boards.
STM32 Blue Pill - I cannot find the STM32F303 anywhere.  The CPU is available, but I am NOT desoldering and soldering such small traces to replace the CPU like others have done.
The Mini and Max  - These are my top two choices.  Teensy 4.0 is readily available on Amazon which leads me towards the MiniPCB.  The MaxSTM looks to require the STM32 CPU, though there are many versions.  Is this the correct one https://tinyurl.com/3xzau3hz?

Welcome all opinions and votes!

Otto


ssalb
 

I’m not an expert and have only ever built OnStep with the Fysect board, but I must say I’m very happy with it. I picked it pretty much for the same reasons you mentioned, something that just works with minimal to no soldering. 

The issues I had while flashing were only because I didn’t fully understand what exactly I was doing, but after that, I’ve flashed it several times, changing gear ratios, adding wifi and a focuser. All without problems.


Chris Whitener
 

I have just finished a comparison of three boards.  FYSETC S6, MaxESP32, and MiniPCB2.  I am waiting for Howard to review.

The result is that with careful settings all three boards seem to work fine for me, slewing a 65lb scope at 3degrees/second.

Personally the choices are not about slew speed.  The 3d boards are changed at whatever point the 3d community needs them.  I already have 3 different versions of the FYSETC.

Of the Howard designs, I like the ESP32 based unit(MaxESP3).  It reflashes easily and has plenty of speed.

The Teensy(4.0) based board has an internal RTC and is the runner up only because the signal to the stepper cannot be set to pulse which may mean nothing to most setups.

All the STM 


Khalid Baheyeldin
 

On Mon, Jan 17, 2022 at 02:17 PM, Otto wrote:
Fystec - Great all-around, but seems to be vulnerable to screw-ups and finicky about flashing the software.
Screw-ups that happened, from what I remember, is not setting the USB 5V jumper correctly while connecting 12V.

It is finnicky when flashing only if you have a chatty GPS (NEO 7M). You need to try several times, but eventually the board will come up in DFU mode.
If you use the ATGM336H GPS, there is no such issue.
Just make sure you insert the USB cable into the PC side before you power up with the Boot0 jumper set to flashing.

One downside for the FYSETC S6 is that if you want it with all the toppings, wiring can become a nightmare.
You will need a daughter perfboard, and lots of wires coming out from the S6 to that daughter board.
If you don't use things like thermometers, weather sensor, ST4 port, ...etc. this is not an issue.

Wemos R32 / CNC V3 - Seems like Ken Hunter or George Cushing has these as a package which is very convenient.  But I have seen many posts with difficulties and unpredictability with these boards.
I agree that there are many posts with issues with these boards. I think it is largely due to the very wide variability of manufacturing quality by different outfits that make them.

STM32 Blue Pill - I cannot find the STM32F303 anywhere.  The CPU is available, but I am NOT desoldering and soldering such small traces to replace the CPU like others have done.
The pandemic has made the STM32F103 module very scarce and very hard to find.
I have a spare module that you can have for $5 plus shipping ($12 to $15?), but that means it will be too expensive for what it is.

The replacement faster and more capable STM32F303CC from RobotDyn is also out of stock.

The Mini and Max  - These are my top two choices.  Teensy 4.0 is readily available on Amazon which leads me towards the MiniPCB.  The MaxSTM looks to require the STM32 CPU, though there are many versions.
If you don't need the additional features of a Max, then the MiniPCB is a tried and tested board.
George Cushing sells them.


Peter Boreland
 

Otto,

I just completed my build using the MaxESP3. I was able to squeeze in a 4 digital Volt/Amp meter after modifying it:), which I use to balance my axes.  In this build my drivers are external to the controller,.  I am thinking of changing out the power connectors for 2 pin aviation plugs to avoid any possibility of power disconnection to the motors.

Peter


 

On Mon, Jan 17, 2022 at 09:40 PM, Peter Boreland wrote:
Otto,

I just completed my build using the MaxESP3. I was able to squeeze in a 4 digital Volt/Amp meter after modifying it:), which I use to balance my axes.  In this build my drivers are external to the controller,.  I am thinking of changing out the power connectors for 2 pin aviation plugs to avoid any possibility of power disconnection to the motors.

Peter

Very nice Peter!  On the volt/Amp meter, how do you diagnose if you are imbalanced?  Are you looking at balance in both the RA/Dec axis?
Do you have a picture of the internals you can share on how you wired/connected everything?
Thanks!


 

On Mon, Jan 17, 2022 at 07:01 PM, Khalid Baheyeldin wrote:
If you don't need the additional features of a Max, then the MiniPCB is a tried and tested board.
George Cushing sells them.
Thanks Khalid and to all who have responded.  I've got a message into George.  I'm thinking of the MiniPCB route.


Peter Boreland
 

On Mon, Jan 17, 2022 at 08:08 PM, Otto wrote:
On the volt/Amp meter, how do you diagnose if you are imbalanced?  Are you looking at balance in both the RA/Dec axis?
Otto,

The ammeter is in line with the ground between the external connector and the PCB.  Doing one axis at a time, one is looking for the current draw when slewing to be the same CW and CCW. This particular ammeter measures up to 3A. 

Peter


Khalid Baheyeldin
 

On Mon, Jan 17, 2022 at 11:11 PM, Otto wrote:
Thanks Khalid and to all who have responded.
One more thing about the MaxSTM: if you want to stay with the TMC2209, then
this board is not for you. It requires either TMC2130 or TMC5160 only, per a recent
long thread on this group.


George Cushing
 

No, that F411 won't work. Left pin positions are not the same as the PCB's.


The problem with the D1 R32 CNCV3 is that folks are drawn in by the cost and then want a silk purse. It is an excellent in inexpensive goto controller for someone whose interests are limited to basic goto control. Yes, in it's basic form it doesn't have many features. The problems arise when users attempt to add those features. A lot of forum time is spent dealing with various failed attempts at these upgrades. 

When I saw what Roman Hujer had put together with his R32 Shield, I immediately realized that it addressed three unmet needs. First, it permitted tapping into the full power of the D1 R32's ESP32 and made adding features like PEC, Tone, RTC, WiFi, etc. a lot less problematic. Second, it filled a hole left by the "demise" of the $2 Blue Pill, which made a $30-35 controller kit possible. Lastly, it gave me a controller that I could offer assembled for under $30 for those that preferred to avoid DIY..

I've only had problems with a couple D1 R32 modules and at least one was abused by myself. I credit Roman with my success. He gave his Shield its own power supply, so I haven't seen or heard of any of the power problems others have struggled with.

I have some STM32 controller parts and have been playing with make a daughter board to adapt the PCB to the Teensy. Roman also has designed a Teensy 3.2 based mini PCB that takes advantage of the 3.2's RTC.


Khalid Baheyeldin
 

On Tue, Jan 18, 2022 at 01:24 PM, George Cushing wrote:
It is an excellent in inexpensive goto controller for someone whose interests are limited to basic goto control. Yes, in it's basic form it doesn't have many features. The problems arise when users attempt to add those features. A lot of forum time is spent dealing with various failed attempts at these upgrades.
I agree with what George said.
The R32+CNCv3 suffers from these two issues:

- Variable quality from various manufacturers, and no clear advocated "safe" version.

- Trying to cram features into a pin-poor controller, giving rise to all these support questions.


 

On Tue, Jan 18, 2022 at 01:06 PM, Khalid Baheyeldin wrote:
On Tue, Jan 18, 2022 at 01:24 PM, George Cushing wrote:
It is an excellent in inexpensive goto controller for someone whose interests are limited to basic goto control. Yes, in it's basic form it doesn't have many features. The problems arise when users attempt to add those features. A lot of forum time is spent dealing with various failed attempts at these upgrades.
I agree with what George said.
The R32+CNCv3 suffers from these two issues:

- Variable quality from various manufacturers, and no clear advocated "safe" version.

- Trying to cram features into a pin-poor controller, giving rise to all these support questions.
I am not looking for tons of features, basically just replicate what I have in my MKS...Two drivers, one BHC, one WiFi module (oh, and an external 5V fan).  So maybe I should take a second look at the R32 / CNCv3.

This recent thread might be evidence on the trouble with these boards.

main@onstep.groups.io | Duplicate Boards everywhere


Khalid Baheyeldin
 

On Tue, Jan 18, 2022 at 02:28 PM, Otto wrote:
I am not looking for tons of features, basically just replicate what I have in my MKS...Two drivers, one BHC, one WiFi module (oh, and an external 5V fan).  So maybe I should take a second look at the R32 / CNCv3.
Any board can add a fan, in theory. But there has to be enough power to run it, and at least one pin to turn it on and off (from the OnStep Android app, or some other OnStep client that can).

The FYSETC S6 provides for multiple fans, and its circuitry and power supply are designed for that.
A quick look at the R32 Wiki page does not explicitly list a fan.