Working on a Raspberry Pi shield for DLP 3d printers
Posted: Fri Aug 08, 2014 3:42 am
Hi,
I have been following this forum since I decided to build a DLP 3d printer and the first thing I missed was an electronic board that could handle the printing process by it's own, without a PC like almost any FDM 3d printer.
I wanted to make my own board and I have some programming skills but I lacked a good electronics background, so I started to learn pcb design and electronics. Now I'm still a bit newbie to the electronics world but I have a first prototype in a protoboard (that can handle one stepper motor, a 16x2 display, some buttons, and powers the pi by itself to avoid extra power cables) and a first piece of software that reads the files generated in Creation Workshop and moves the stepper motor.
The problem I found is that the Raspberry Pi is not capable of doing realtime tasks like sending step/dir pulses to the stepper drivers, and the motors are not moving smoothly. This could cause step missing because sometimes the motion stops and starts abruptly in the middle of a move.
As I don't want to add an Arduino to the mix, because it will start to make the thing bulky and more expensive, I'm working on a new prototype with an integrated motion control chip that will handle the real time tasks by itself, so that the Raspberry Pi only needs to send target position commands
That being said, what would you want to have in a raspberry pi shield for your DLP 3d printers?
- 2 stepper drivers (or 3?)
- 16x2 display and buttons for menus and headless working
- Servo outputs?
- Some switch inputs
- additional SD card reader? (the SO uses the rpi one, but there are a pair of USB ports available to use a pen drive)
- ...?
I have been following this forum since I decided to build a DLP 3d printer and the first thing I missed was an electronic board that could handle the printing process by it's own, without a PC like almost any FDM 3d printer.
I wanted to make my own board and I have some programming skills but I lacked a good electronics background, so I started to learn pcb design and electronics. Now I'm still a bit newbie to the electronics world but I have a first prototype in a protoboard (that can handle one stepper motor, a 16x2 display, some buttons, and powers the pi by itself to avoid extra power cables) and a first piece of software that reads the files generated in Creation Workshop and moves the stepper motor.
The problem I found is that the Raspberry Pi is not capable of doing realtime tasks like sending step/dir pulses to the stepper drivers, and the motors are not moving smoothly. This could cause step missing because sometimes the motion stops and starts abruptly in the middle of a move.
As I don't want to add an Arduino to the mix, because it will start to make the thing bulky and more expensive, I'm working on a new prototype with an integrated motion control chip that will handle the real time tasks by itself, so that the Raspberry Pi only needs to send target position commands
That being said, what would you want to have in a raspberry pi shield for your DLP 3d printers?
- 2 stepper drivers (or 3?)
- 16x2 display and buttons for menus and headless working
- Servo outputs?
- Some switch inputs
- additional SD card reader? (the SO uses the rpi one, but there are a pair of USB ports available to use a pen drive)
- ...?