I have done some preliminary design work for a low-cost 32-bit 3D printer controller board. The idea is to make a board that would cost less than Arduino Mega/RAMPS clones to build in quantity, but have much more processor power and so capable of running more advanced software. My provisional specification is:
* ATSAM3S4B processor (which costs less than half the price of ATMEGA2560), 64MHz clock speed, 256K flash, 48K RAM, native USB port.
* 5 stepper driver sockets (XYZ plus 2 extruders). Each would accept either a standard stepstick-type driver, or a modified stepstick with an additional pin for digital current control.
* Two Z motor connectors to make it easy to connect two motors in series.
* One heated bed output, rated at 20A.
* Two hot end heater outputs rated at 10A.
* Two outputs for 12V fans etc., one with PWM, the other without.
* Three endstop inputs
* Three thermistor inputs
* A 4-pin connector for supporting several different kinds of Z probe.
* Digital control of stepper motor current (when modified stepsticks are used) split into 2 channels. One channel would control the XYZ currents, the other would control the extruder motor currents.
* 12 to 24V (max 30V) input voltage range.
* On-board 5V 1A regulator, probably a linear one for simplicity and low cost, with provision for attaching a heatsink.
* On-board SDHC card socket.
* Expansion connector with about 8 or 10 I/O lines, for connecting control panels, servos, etc.
Before I put any more work into this, I would like to know whether others think there is a market for such a board. There is already one low-cost 32-bit board - the AZSMZ Mini, which has many of the same features (but not the digital stepper motor current control) and costs $60 plus shipping from China and import tax. Another factor is that many people who are looking for something better than Arduino/RAMPS may rather pay extra and buy a board with Ethernet support, of which there are already several (Duet, Smoothie, and the recently-announced Alligator).
Comments please?
* ATSAM3S4B processor (which costs less than half the price of ATMEGA2560), 64MHz clock speed, 256K flash, 48K RAM, native USB port.
* 5 stepper driver sockets (XYZ plus 2 extruders). Each would accept either a standard stepstick-type driver, or a modified stepstick with an additional pin for digital current control.
* Two Z motor connectors to make it easy to connect two motors in series.
* One heated bed output, rated at 20A.
* Two hot end heater outputs rated at 10A.
* Two outputs for 12V fans etc., one with PWM, the other without.
* Three endstop inputs
* Three thermistor inputs
* A 4-pin connector for supporting several different kinds of Z probe.
* Digital control of stepper motor current (when modified stepsticks are used) split into 2 channels. One channel would control the XYZ currents, the other would control the extruder motor currents.
* 12 to 24V (max 30V) input voltage range.
* On-board 5V 1A regulator, probably a linear one for simplicity and low cost, with provision for attaching a heatsink.
* On-board SDHC card socket.
* Expansion connector with about 8 or 10 I/O lines, for connecting control panels, servos, etc.
Before I put any more work into this, I would like to know whether others think there is a market for such a board. There is already one low-cost 32-bit board - the AZSMZ Mini, which has many of the same features (but not the digital stepper motor current control) and costs $60 plus shipping from China and import tax. Another factor is that many people who are looking for something better than Arduino/RAMPS may rather pay extra and buy a board with Ethernet support, of which there are already several (Duet, Smoothie, and the recently-announced Alligator).
Comments please?
