32bit controllerboard for an A8 Plus?

Hi, as I need a bigger build plate, I just ordered an A8 Plus. I'm sure I can get it work in stock-configuration, but I'd like to upgrade it to a modern 32bit controller board, soon.

I'd also like to keep the stepper drivers on an easy to swap socket like the TMC22xx-series drivers. Also I need enough space to place StepStick-Protectors.

So which controller board in a decent price range would be the perfect choice in 2021?
In best case it might be compatible with several firmwares like Marlin or RepRap, to be able to look over the line.

An cheap BLtouch clone I already have here for the A8 Plus.

Using SilentStepStick running in StallGuard-mode would also be nice - or might StallGuard have any disadvantages?

"Perfect choice" really depends on style of connectors built into the printer.

You are probably looking at BTT SKR 1.4 Turbo or BTT Octopus plus.

The snag with buying controllers at the "decent price range" is you might have to return one or 2 before getting one without any build errors.

You might consider SPI or UART connection for the drivers. Even less chance of missed steps.

It is quite likely that the supplied hot end and extruder won't go too fast anyway, but you'll only find out by trying.

EDIT: I checked, SKR 1.4 Turbo only supported in Marlin, if you want choice of Reprap firmware you have to go V2 SKR.

This is unclear from the Reprap firmware website. They just link direct to Duet boards, they don't actually test for compatibility.

Edited 3 time(s). Last edit at 12/18/2021 10:45AM by DragonFire.

If you want to go ask yourself;-

[www.reprapfirmware.org]

It pretty much boils down to processor type, and only old forks are definitely OK with the older BTT hardware.

I'm getting into Klipper myself.

Klipper would be an option, too. So which hardware would you use for Klipper/Marlin-Compatibility?

Well, I just use an 8 bit RAMPs compatible controller. Raspberry Pi 3 (got a couple of these) to run Klipper on.

The Pi plugs into the Usb port of the 8 bit controller. I use a network connection to access the Klipper control panel.

The key part is upgrading the motor drivers, it saves the 8 bit controller from having to calculate any of the pulses. The drivers do that.

Not that Klipper can't support 32 bit controllers. It can.

Marlin does a pretty good job on an i-bot like the A8, mind you. You might be surprised how good it can do with the supplied controller on Marlin 1.1.X.

The slowest axis will be Y. It's moving the most weight. ("Hardest job to accelerate", which is when you start thinking about a 24V supply for the whole thing).

As the plastic goes down, the built plate gets heavier. To be smart, you want to work out how fast it can go accurately carrying a deadweight.

Rather than it missing steps half way through a print because the load is greater than the torque available to move it quickly.

So you'd prefer TMC stepper drivers using SPI or UART?
What's the disadvantage in combination with Marlin?

And running an Ramps-board using SPI/Uart-stepper drivers makes the upgrade to 32bit useless?

As it's a used kit never assembled, it could be either 12V or 24V. I'll see when it arrives.

Edited 1 time(s). Last edit at 12/19/2021 01:40PM by cysign.

2209 with UART or TMC2130 spi. The latter is better spec but more expensive. Either offer an upgrade path to 24V if desired. 2208 tend to run hot even at 12V,

Marlin can use such defined in config.h. No disadvantage beyond having to use Marlin. It's a bit quirky.

[marlinfw.org]

32 bit controller will give you more headspace for computing moves, also firmware flashing via sd card (Arduino IDE no good here, so you will have to learn how to compile and upload 32 bit style rather than using Arduino IDE. Far from useless.

Here's the thing - setting it up as "standard" will give you some idea of what the config settings should be. And what the limitations of printing speed are.

Plus, it gives you time to read up on different controllers and maybe come across a bargain or two.

Klipper is a LOT of work to get set up if you are not used to Raspi Pis or Linux. Plus you might not have HDMI for monitor connection, usb keyboard and mouse, sd flashing. The most recent Pi Zero 2 has much the same computing power as a Pi 3. Less than 20 bucks, but it does use a lot of miniaturized connectors.

A standard "Chinesium" clone hot end and extruder top out about 130mm per second anyway.

[www.youtube.com]

Here's an 8 bit controller on a Delta with Klipper but hot rodded to the max for comparison. (Modded Volcano, Flex3Drive extruder).

[www.youtube.com]

Mind your, your build area will be like 16 times as big. Going fast isn't why you paid money for the thing. Going big and precise are what you are aiming for.

Edited 2 time(s). Last edit at 12/19/2021 03:25PM by DragonFire.

What's your opinion on the FYSETC E4?
Disadvantage: stepper drivers aren't replaceable. But it should be compatibpe to Marlin.
What's the maximum steps per second compared with an Atmage328/Arduino Mega?

No max endstops, filament sensor, 2nd Z motor driver. Very compact. Probably too compact from a heat / cooling point of view.

Supposed to be flashed at the factory with Marlin, to the extent that the manufacturer recommends a custom fork of Marlin.

[www.fysetc.com]

With UART 2209 steps per second should depend on the 2209s, not the processor.

No Klipper support (might be an issue with compiling for the processor, not sure).

[www.reddit.com]

Not what I'd choose for a large volume printer. If your budget will stretch, the SKR E3 V3 should give you more options, but no WiFi.

[www.aliexpress.com]

WAIT until you've built the thing with an 8 bit board. That should give you a good idea of how fast you can move the Y carriage with a couple kilos of plastic already extruded onto it.

All the 32 bit and UART/SPI goodness do is let your move at the same speed on multiple motors without missing steps. They don't apply more torque to the motors.

As there seem to be A4988 on the stock board, I'd like to upgrade it, soon. I'm on vacation till new year - so I have plenty of time right now
There's no need to use wifi. At the moment I prefer printing from SD - which can also be a bottleneck on an ArduinoMega2560.
Might processor load be a point when using an Mega2560 running into UART/SPI StepSticks while reading files from SD card?

So the cheapest solution would be just changing the board for an Mega2560 and buying drivers+Ramps 1.6 Plus, which shall already be prepared for SPI/Uart.
I also have found an solution for upgrading a Ramps based system into an 32bit system:
[www.panucatt.com]

Just found the MKS Robin E3. Also there's a MKS Robin Nano (MKS Robin Nano v1.2 is my current favorite).
It's cheap and I'd be able to upgrade Wifi later. - which supports to exchange drivers
The Robin seems to be supportet both from Marlin, and Klipper.

//edit: The Robin has native BLTouch support (which might work for my clone, as well).
Not sure abour the driver connection yet.
As well as it supports 24V.

Edited 3 time(s). Last edit at 12/20/2021 10:34PM by cysign.

In terms of "processor" overload... UART/SPI tells the driver to go do so many pulses and micropulses to a given motor, via serial connection.

That is a tiny fraction to the amount of processor load when it has to do all the pulse timing on its own.

Oh well. If you do get it sooner rather than later, you will get opportunity to work out how to compile and upload firmware to it.

Good luck finding. Personally I'm going to get cracking on Klipper.

If I can do that on 8 bit, 32 should be pretty easy.

Edited 1 time(s). Last edit at 12/21/2021 01:24AM by DragonFire.

Robin Nano v3 seems to be what I'm looking for:

[github.com]

Support of Marlin, Reperier, and Klipper
Also supports proprietary color Touchscreen, Wifi, USB drives.


//edit: just ordered it. Couldn't find any German dealer, so i ordered on Ali. Looks like even this board faces the semiconductor shortage

Edited 3 time(s). Last edit at 12/22/2021 08:13AM by cysign.

Machine arrived by today. It already runs on 24V - so upgrading shouldn't be too much hussle
Going to build it together during the days.
Robin Nano V3 might arrive in 2 weeks...
Have a great X-Mas and thanks for your input!

Very good start. You too.