I slowly started working on modernizing an older semi broken cnc a few years ago. I got gecko drivers and then got sick so it was shelved for years. Now I’m looking at getting an driver board. Back then I was sure that meant linuxcnc, but now fluidnc and grblhal are options and they play better with millmage.
Do driver boards that have those small stepper daughter boards have the ability to control bigger drivers? Because I have some old 3d printer gear I could probably reuse with grblhal if so (an Arduino mega with driver slots, 4 axis). Otherwise I’ll pick a fluidnc board meant for gecko drivers.
I’m a FluidNC fan, so I’d recommend one of the supported controllers.
The 6x controller has dedicated screw terminals for the Step, Dir, and Enable pins for external drivers and should work with the Geckos.
The small step sticks (like the A4988) use the same Step, Dir, and Enable pins, so you should be able to attach the Gecko drivers to an old 3D printer board.
On a more experimental build, I’ve tapped those pins with jumper wires and attached an external DM542 driver. That works well in my case, but there might be electrical issues because these step sticks usually have an integrated opto-coupler.
Alright so relay breakout + separate controller board. That sounds fairly straightforward. I’ll have to look into some more. I wonder if I can just use an Esp32 and use serial communication to the motor drivers with level shifters.
Yes, you can use a bare ESP32 with FluidNC, but your stepper drivers need to be connected to free GPIO pins of the ESP. The “communication” to the drivers is not UART/serial.
You are correct that level shifters will be needed because the ESP32 operates at 3.3V and the Stepper most likely expects 5V.
You’ll also need additional circuits to attach the spindle (0-10V, or RS485)
If that doesn’t scare you off, and you have the parts available, go for it!
I have more time than money and need stuff I can tinker with slowly over the months to keep my mind busy, so programming an Esp32 sounds like lots of fun
I have old prototypes for the laser leveler I had started working on that has a built in shifter and esp32 all ready to go. It even had a small motor driver so I should be able to recycle it bit of my code / use that to get back into the whole controlling motor drivers again.
And you’re right, I’m pretty sure my vfd has a serial port! I’ll probably have to add a tach though, which should not be too difficult.
Thanks for all the input. The hardest part of open sourced projects I find is always getting the initial footing. It’s such an open field, even with documentation.
Which Gecko board do you have? If they are standalone any board that supports external drivers will work well. I have both the Flexi-HAL and SLB-EXT from Sienci labs and like them a lot for grblHAL.
Just some DM556. I’m glad to hear it can just run off normal gpio, it really shouldn’t be hard. I had forgotten about how I had already programmed an Esp32 to run a small driver. Looking forward to it.
Honestly at this point I think wiring the drivers to the motor will be harder lol. It’s these old huge steppers with next to no online information. It’s going to be a good hobby to keep me busy when I can’t sleep, just diagnose and troubleshoot wiring for hours
1-directly from the pins where the mini drivers are usually seated
2-install a mini driver and that drives the big external driver?
Or 3- install jumpers where the mini drivers go between different pin locations but connect the external driver at the motor output pins rather than the mini driver socket?
I’ve used the DM556’s on quite a few projects. They are pretty simple drivers to wire in especially being bi-polar, the stepper wire configs are pretty simple. If they are 4 wire motors you just need to figure out the pairs. 8-wire or 6-wire motors are a little more complex, but you can’t hurt the motor getting it wrong, so trying things isn’t a big deal.
Thanks. The connector has 5 pins so it might be unipolar (oops), but I’m trying to figure out if the cable has a grounding jacket. I’m letting Claude translate the choppy pdf of the old Italian manual overnight
