In the process, because I wanted to upgrade my own printer to a 3 head mixer extruder, I designed a board with 6 stepper drivers, and I'm now using it in my printer, together with an ESP8266 acting as wireless bridge, and couldn't be happier with it. Everything works, is smooth, can control it remotely, etc etc.
So I have been thinking a lot what I want to do with my board design. I have been considering several things:
- First is there any need for a new printer board at all? From what I have found, most boards have 4 or 5 stepper drives. With the new mixing heads seems like printers may be needed 3 or more steppers just for the extruders, then there is printers that use more than 3 steppers for the move. So 6 seems to be a minimum.
- If there is interest in an STM board with enought steppers, should I do a kickstarter campaign to get the funds, and bring the design to commercial quality and volume prices?
- Should I release the design after a successful kickstarter as open hardware, or should I keep the design propietary to control where it goes?
- If I go for a kickstarter or other crowdfunding campaign, and fails to get traction, should I still release the hardware designs I have done so far?
But if a crowdsourcing doesn't get funded, should I release the designs? It weights a lot on me what happened to Bobc with the RAMPS-FD: He opened the design from the start, then Geetech and possibly others started producing them, and there are some flaws with that initial design that make it unsafe (the Hotend and Bed FETS can be open from the moment the board is powered up, and if something goes wrong rather than go off, they may stay open, and potentially burn the printer, or something worst...) He has since released better designs, but all cloners are still selling the defective one in Ebay and aliexpress. The result is that a board that could be great was cloned while unfinished, and gave it a bad name, and the cloners are exposing people to fires and damages to their printers.
I'd love to get you guys ideas an opinions:
Experience with crowdfunding, whether an STMF1/F4 based board is a good idea or there are too many out there, whether opening the design if it doesn't get finished is a responsible thing to do, and any other opinions you may have.
To be clear, my day job is not related to this at all, I don't really expect to make much money out of this even if it was very successful, but it would provide the incentive to continue development and the funds to get it to the next level.
All opinions are welcomed, against or in favor of any option, and any experiences that you want to share.
This is a rough description of what I have so far. There are pictures of one of the prototypes in the allpcb review post:
-4 ADC inputs for thermistors.
-4 Endstops inputs (using 3 for XYZ, and an extra left for anything else)
-Heatbed separate power, and 1 mosfet to control it, tested
-2 high power mosfet outputs for hot ends, tested
-1 PWM Fan output, tested
-2 Fan outputs always on.
-6 pololu steppers connectors, tested A4988 and DRV8825
-SDCard and LCD connectors. Tested with 2004 LCD and sdcard display.
-Onboard eeprom for settings (I'm using fram atm), tested
-ESP-01 connector for WIFI bridge, tested with the excellent ESP3D firmware
-Multiple expansion pins, currently using 2 to control a Laser module, and working great.
What I want to add in my next revision, which will be the final or personal usage if I don't decide to go any further:
-Dedicated connector for BLTouch (should work currently fine with the expansion pins I have available)
-Dedicated connectors for Laser/CNC control. Laser needs 1 or 2 pins, CNC normally 2. Currently working with expansion pins.
-Possibly replace the high power TH mostets for SMD ones.